Cannabis Plant Problems

Cannabis Plant Problems
problem fixing in marijuana plants

The following possible solutions were specially made to fix a whole host of plant problems and will help you to get your plant(s) healthy again.

Remember catching and solving problems quickly means bigger and more potent buds.

Nutrient problems

Correct PH levels – pH fluctuantions

pH Fluctuations in Marijuana plants
pH Fluctuations on Cannabis

The pH scale is how growers measure the acidity or alkalinity of the soil and water around their plant.

The scale ranges from 1 to 14, with 7 being neutral pH. 1 is the most acidic while 14 is the most basic (alkaline).

When you are watering your plants, you want to be absolutely sure that the pH levels are appropriate, otherwise the plants can be damaged and their health can deteriorate.

Although hydroponics systems can sometimes support a cannabis plant with a pH of as low as 5.5, the ideal range is somewhere around 6.Testing pH levels is extremely easy.

All you need to do is purchase test strips from a local gardening supply shop or a ph meter.

This will help you avoid over or underfeeding your plants.

At the same location you pick up test strips, you should be able to purchase commercial mixes of soil that easily let you modify and stabilize the pH of your own soil.

Ph strips and meters are also online available at this link.

Boron Deficiency

Boron Deficiencies in Marijuana Plants
Marijuana with Boron Deficiency

One of the rarer deficiencies is boron. It’s not common for cannabis cultivation, but it can certainly damage the plant’s potential growth.

The most visible signs of boron deficiency are when the growing tips of the plant begin to turn brown or gray.

The growth itself will slow significantly or stop if there isn’t enough boron.

In addition to the damage experienced by the growing tips, the leaves may start develop dead spots.

They will be small and scattered, and might go easily unnoticed.Make sure you take counteractive measures to fix boron deficiencies right away.

Fixing the problem usually starts with adjusting irrigation processes, and making sure you’re getting the boron back into the environment.

Boric acid is a simple and common choice for growers, but compost and natural mixes are also potential options to bring the levels back to normal.

Calcium Deficiency

Calcium Deficiencies in Marijuana Plants
Marijuana with Calcium Deficiency

Calcium deficiencies are relatively uncommon for outdoor growers but are not uncommon for indoor growing and users of hydroponics systems.

Some areas also have water supplies which don’t contain calcium, and if growers don’t add calcium to their irrigation reservoirs, there likely won’t be enough for the plants to thrive.

Additionally, if you’re growing in a hydroponics system and you’re only using water and nutrients in a solution, then you might be missing a good source of calcium.

Calcium deficiencies will usually display symptoms of big dead patches on unusually dark leaves.

The symptoms of calcium deficiencies will usually first arise in the older growth.

Branches may become weakened significantly, and any additional weight or stress could cause them to crack or break off.

If you don’t address a calcium deficiency early, the plant may also develop some issues in the root systems.

Thankfully, treating a calcium deficiency is usually a pretty simple process.

Growers often use lime, applying it to the soil or substrate and letting the plant take it from there.

Copper Deficiency

Copper Deficiencies in Marijuana Plants
Marijuana with Copper Deficiency

Copper deficiencies in cannabis plants are relatively uncommon, but they can cause a lot of damage to new growth.

The initial symptoms will be a necrosis of the plant matter in new leaves.

This will cause the leaves to look brownish or blue-gray at the tips.

The new leaves, flowers and other new growth on the plant can also come in limp and weak if there isn’t enough copper.

Since copper is easily renewed in the plants environment, and very important for letting the plant thrive and mature, you need to make sure you do your part.

There are a number of fungicides which contain copper.

Iron Deficiency

Iron Deficiencies in Marijuana Plants
Marijuana with Iron Deficiency

Iron deficiencies are not uncommon for cannabis plants.

The first area growers will see evidence of an iron deficiency will be in the new growth of the plant, especially the leaves.

The upper leaves will usually be the most affected, becoming discolored and yellowing distinctively.

The veins of the leaf will remain green, but the leaf itself just won’t have enough chlorophyll if the plant has an iron deficiency.

Iron holds a vital role in the production of chlorophyll in cannabis plants.

Beware: an iron deficiency and a magnesium deficiency can look very similar to one another.

The main difference is that an iron deficiency will primarily affect new growth on the plant.

That means the top leaves will be affected far more than those at the bottom and middle of the plant.

Iron deficiencies often occur at the same time as improper pH levels, so you’ll need to take that into account.

It’s also common for iron deficiencies to occur in conjunction with manganese and zinc deficiencies, so keep an eye out for those.

Like with many other nutrient deficiencies, using an all-around nutrient provider like Marijuana Booster is going to work best.

You can also choose a foliar feeding method that includes a chelated iron fertilizer.

This will also help with zinc and manganese, which is helpful since deficiencies in iron, manganese, and zinc often occur together.

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You can also use iron chelates, iron oxides (Fe203 or FeO), or iron sulfate (FeSO4), which should be added filially and right into the planting medium. Surprisingly, you can also just use rusty water.

Also similar to other nutrient deficiencies, a marijuana plant with iron deficiency could be suffering from an unbalanced pH level.

This occurs more often in soil than in a hydroponic system.

Read the article How to measure the pH of your soil and test the pH of the soil around your plant’s roots to make sure this is indeed the problem.

In soil, the pH level should be between 6.0 and 7.0. Roots absorb will absorb iron best if you can ensure the pH level is low enough, so try getting it down to at least 6.5 if you can.

In a hydro system, iron will be taken in by the roots most efficiently when the pH is between 5.5 and 6.5.

In order to fix the pH level of your system, simply flush out the entire system with fresh water that has the proper pH level as well as a boost of nutrients to restore the balance.

Magnesium Deficiency

Magnesium Deficiencies in Marijuana Plants
Marijuana with Magnesium Deficiency

Magnesium deficiencies are another relatively rare occurrence for outdoor growers of cannabis, but it’s found indoors and with hydroponics systems.

Usually, it will affect the lowest leaves of the plant at the beginning, causing them to yellow and weaken.

Left unchecked, the leaves will die. This deficiency can also work its way up the plant from bottom to top until it reaches the crown.

Magnesium is a very important element for the development of chlorophyll in the cannabis plant, so don’t let the problem worsen, especially in the early stages of growth.

The easiest and most common way to fix a magnesium deficiency is the application of Epsom salts.

Be careful, though, you want to make sure you’ve diagnosed the deficiency correctly before trying to fix it.

If you apply too many unneeded nutrients, you could be causing a whole new problem instead of fixing the real issue.

Manganese Deficiency

Manganese Deficiencies in Marijuana Plants
Marijuana with Manganese Deficiency

Manganese deficiencies are also fairly uncommon in cannabis cultivation.

You’ll usually find them occurring in tandem with zinc and iron deficiencies, so remember to carefully test and analyze your plant’s environment when treating them.

A manganese deficiency will display symptoms in new growth, primarily in the leaves.

The leaves will develop dead spots and begin to yellow. On the other hand, too much manganese can inhibit nutrient absorption and cause iron deficiencies.

Manganese is a very important element for the creation of chlorophyll and also for the production of nitrates.

Make sure you have plenty of manganese in your nutrient solution or plant substrate.

Getting manganese in a water-soluble form is always a good idea, since it simplifies the application process. Many growers also prefer compost or greensand.

Molybdenum Deficiency

Molybdenum Deficiencies in Marijuana Plants
Marijuana with Molybdenum Deficiency

Molybdenum deficiencies are very uncommon, but if they do occur, they will cause some unpredictable and negative effects on your cannabis plant.

Without enough molybdenum, the plant’s middle leaves will begin to yellow, and any new foliage will grow out warped or stop growing entirely.

The shoots will begin to curl, and the leaves can develop a strange crimson hue at the tips.

Molybdenum aids primarily in the development and production of ammonia for the plant.

Like other deficiencies, a molybdenum deficiency is often caused by the pH level.

If the pH value is low near the roots, there is a higher chance of your plant having trouble absorbing molybdenum.

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Therefore, it is crucial that you monitor (or fix) the pH level of the soil that is nearest to your marijuana plants’ roots.

If your system is based in soil, the pH level should be between 6.0 and 7.0 in order to best absorb molybdenum.

Many growers even avoid pH levels below 6.5 if they think a lack of molybdenum might be the problem.

If you are using a hydroponics system, make sure the pH range is between 5.5 and 6.5.

To restore the pH to the optimum level, flush the entire system through with fresh water of the desired pH level, after first mixing in nutrients that work well with marijuana and include molybdenum.

This should be enough to restore the balance and remove any potential nutrient salts that were present and blocking your plant’s roots from absorbing molybdenum.

Nitrogen Deficiency

Nitrogen Deficiencies in Marijuana Plants
Marijuana with Nitrogen Deficiency

Nitrogen is one of the most important nutrients for healthy plant growth, and because it’s so heavily used by cannabis, it’s not uncommon for plants to develop nitrogen deficiencies.

Nitrogen is used for a wide variety of plant processes, from photosynthesis to the production of vital amino acids.

Symptoms of a nitrogen deficiency are yellowing leaves. If the deficiency is left unchecked, the yellowing leaves can wither and die.

Nitrogen deficiencies will usually begin in the bottom leaves of the plant and then spread up to the top.

The best way to treat a nitrogen deficiency is to make sure that you’re using a fertilizer which contains the right ratio of macro nutrients: nitrogen, phosphorus, and potassium.

Plants require extra nitrogen during the vegetative stage of growth, so make sure they are getting enough!

If you need a quick nitrogen boost and don’t have time to worry about long-term fixes, you can use bat guano or compost to help improve the plant’s health.

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Phosphorus Deficiency

Phosphorus Deficiencies in Marijuana Plants
Marijuana with Phosphorus Deficiency

While not as common as nitrogen deficiencies, phosphorus deficiencies are a definite possibility, especially in hydroponics systems.

The initial symptoms of a phosphorus deficiency are darkening foliage and slowing growth. The leaves will begin to curve and curl and develop a brown hue.

Other plant parts like petioles will also darken, possibly becoming more blue or red.

Phosphorus is most important during the flowering phase of growth, but it also adds structural strength to the roots and stems of the plant.

If your plant lacks phosphorus during the flowering phase, you will limit the potential yield.

To take care of phosphorus deficiencies, try to use a fertilizer which contains a higher ratio of phosphorus than whatever you were using before.

Fertilizers specifically developed for the flowering phase work well, as does bat guano. Water-soluble fertilizers will be your best option for maximum efficiency and ease of use.

Potassium Deficiency

Potassium Deficiencies in Marijuana Plants
Marijuana with Potassium Deficiency

Potassium deficiencies are fairly common in the world of cannabis cultivation. This is because, with most fertilizers, potassium occurs in the lowest ratios.

Compared to the other macronutrients, less potassium is required by the plant.

A potassium deficiency has unusual symptoms: the plant might actually grow taller more quickly and look healthy at first, but keep an eye on the lower foliage.

If the plant doesn’t have enough potassium, the leaves can turn brown and begin to die.

You also might notice areas where growth slows or becomes irregular. Remember that potassium is very important to the transfer of water and other nutrients throughout the plant.

This means that if you have a large deficiency, it can affect the health of the whole plant.

To treat your potassium deficiencies, try adjusting the fertilizer mix you are using or add a water-soluble potassium additive.

Sulfur Deficiency

Sulfur Deficiencies in Marijuana Plants
Marijuana with Sulfur Deficiency

Sulfur deficiencies don’t occur too often since most fertilizers will have the requisite amount of sulfur already present.

Symptoms of a deficiency include yellowing of new and developing foliage, as well as stunted growth.

The new leaves may also be narrower and more brittle than they should be.

Sulfur plays an important role in a number of different vital processes, including chlorophyll development and root system growth.

If your plants do develop sulfur deficiencies, they can be easily treated with the application of potassium sulfate or Epsom salts.

Zinc Deficiency

Iron Deficiencies in Marijuana Plants
Marijuana with Zinc Deficiency

Despite the moderately small amount of zinc required in the cannabis plant, zinc deficiencies occur fairly regularly.

Symptoms of a zinc deficiency include twisted foliage growth and yellowing of the veins of the older leaves.

It’s also possible for the plant to begin to lose color and grow paler.

When the flowering phase occurs, the same issue can crop up in the buds, and they might curl or become deformed.

Zinc deficiencies often occur in tandem with iron or manganese deficiencies.

Zinc plays an important role in a number of different plant processes, including plant development and the production of vital enzymes.

Severe deficiencies can cause the plant to wilt or even break the stem.

Because of the linkage between zinc, manganese, and iron, it’s important to be careful when trying to treat a zinc deficiency.

You can resolve zinc deficiency through implementing a micro mix compound containing zinc, iron and manganese. You can also try zinc sulfate, zinc oxide and chelated zinc.

Another option is an excellent product such as Marijuana Booster, which gives your plant plenty of the variety of nutrients it needs, including zinc.

Also, flush your system with pure, pH water that has almost half of the necessary nutrients for your plant which will include, manganese, zinc and iron.

Pay attention and give it a few days to fully recover on the new growth.



Algae on Marijuana plants
Algae on Cannabis

Hydroponics systems are water-based, and without proper care, they can become havens for algae.

Both cannabis and algae thrive in nutrient-rich water environments, but you really don’t want them to be sharing the same space.

Algae will live on the roots of your plants, and thus deprive your cannabis of the nutrients necessary for the plant to develop properly in a hydroponics system.

Not to beat a dead horse, but your best defense is always preventative.

Do your best to minimize the potential for algae growth before it occurs by the taking the proper precautions beforehand.

Because algae and cannabis have similar requirements of water and light, it can be difficult to do this.

The easiest way is to make sure that no light reaches the roots of your plants. Use an opaque, dark material to block out the light. If algae begins to develop, clean it out right away.

Bud rot

Bud rot on Marijuana
Mold or Botrytis on Marijuana

Bud rot (also gray mold or botrytis) is one of the most damaging of the possible infections your marijuana plants can face.

It eats every part of the plant, not bothering to distinguish between buds and flowers or stalks and stems.

The infection can spread very rapidly, so you want to take precautions to avoid letting gray mold take root in your plant’s environment.

The disease prefers a cool but relatively humid environment.

Keeping the temperature in your grow room above 70 degrees Fahrenheit will help, and make sure to monitor the humidity constantly so that it doesn’t get too wet.

Another step can be to change clothes or wear protective gear before going into your grow room. The spores can attach themselves to clothing fibers and

then release in the grow room if the environment feels appropriate.

If all else fails and your plants develop gray mold, there a few different soaps and sprays you can use to help mitigate the damage and treat the plant. Marijuana Plant Protector is the best solution.

Leaf Septoria

Leaf septoria on marijuana
Cannabis leaf septoria

Leaf Septoria (also known as yellow leaf spot) produces yellow spots on the leaves of your cannabis plants.

It’s a fungus which usually pops up on outdoor cannabis plants after they have been exposed to both heat and recent rain.

The yellow spots initially develop on the lowest leaves of the plant and then work their way upwards.

In the worst cases of Leaf Septoria, the entire leaf will turn yellow and begin to crumble. Generally, however, the leaves won’t die off, and the plants will survive.

Despite the fact that it isn’t usually lethal, yellow leaf spot can heavily inhibit the growth of the plant and its eventual yield.

You can prevent yellow leaf spot by keeping the soil well-aerated and applying a fungicidal compound to your compost.

If you still have trouble with yellow leaf spot, you can apply baking soda as a reactive measure.

Powdery Mildew

Powdery Mildew o Marijuana
Marijuana Spore based on fungal problem

Powdery mildew on marijuana is a spore based fungal problem that can affect both outdoor and indoor marijuana gardens.

The spores are transmissible through the air, and being carried by wind means it can be fairly difficult to protect against.

It’s also a very sneaky fungus because the spores can lie dormant in the soil until conditions are just right for them to start growth.

Usually, this is when the environment is warm and highly humid.

Powdery mildew also occurs frequently when the cannabis plants are too close together, and there isn’t enough airflow.

An overcrowded grow room unnecessarily risks damage to your plants.

You can recognize powdery mildew by its white color. It will cover the foliage of the plant and inhibit the photosynthesis process.

If your plants suffer from powdery mildew, there are a number of safe naturally based sprays you can use (including milk and apple cider vinegar) to help deal with the problem.

Mold control also treats powdery mildew.


Algae on Marijuana
Fusarium damages the root systems

This is another fungal issue. Instead of eating the foliage, however, fusarium damages the root systems of your cannabis plants.

Thankfully, hydroponics systems aren’t affected by fusarium since it requires a soil-based substrate to survive in.

Usually fusarium causes wilting in the plant or a more generalized root rot.

Like some of the other fungi, fusarium will sometimes lie dormant in the soil for long periods of time, just waiting to strike.

If fusarium does begin to take hold in the root systems of your plant, there’s very little that you can do to treat it.

First of all, it’s very difficult to spot until it’s too late. Second, although indoor growers can help prevent fusarium by using sterile soil, there’s no way to be sure it isn’t present outside in nature.

Verticillium wilt

Verticillium wilt on Marijuana
Marijuana with Verticillium wilt disease

Verticillium wilt on marijuana is fairly similar to fusarium wilt, except that it is mostly like to appear in soils that are improperly drained or overly full of nutrients The first signs of verticillium wilt are drooping and yellowing foliage.

The fungus will also cause the stem to turn a dark brown at the base, where it makes contact with the soil.

These sorts of fungal diseases are nigh impossible to treat, so it’s of the utmost importance that you practice preventative care.

Try to make sure that your soil or substrate has proper drainage, so that verticillium wilt won’t rear its ugly head.

Because there’s really no way to cure or treat verticillium wilt, make sure that you rotate your crop if you have issues with it, otherwise it will just keep coming back.

Root rot

Root rot on Marijuana
Marijuana with Root rot fungus

Root rot, also known as pythium, is a fungus that will live on the roots of your marijuana plants.

As you can imagine, this isn’t good for the roots, and if it’s not good for the roots, it’s definitely not good for the plant.

Root rot can occur both indoors and outdoors, and in a wide variety of substrates, including the water of hydroponics systems.

Initial symptoms include wilting of the plant, and a change in the color of the foliage to brown or yellow.

Since these symptoms can be caused by a wide variety of issues, you’ll need to check the roots themselves if you want to verify the source.

When a plant is infected by pythium, the roots will begin to change color and eventually the outer layer of the roots will be shed to reveal stringy, weak inner core.

You can help keep your plants root rot free by fastidiously cleaning the hydroponics system and making sure that the substrate drains properly. Remember, preventative care is key!

Damping off

Damping off on Marijauana
Marijuana with Seedling Damping off

Damping off of marijuana seedlings isn’t actually a disease, instead it’s the plant responding to the presence of a disease.

You’ll notice when you see damping that the plant seems like it’s wilting— it may resemble overwatering, but really it’s the roots which causing the issue.

Damping off usually occurs in cannabis seedlings. The plant itself will develop lesions before actually dying entirely.

Again, preventative care is the only real way to deal with damping off and other fungal disease-related problems.

Usually, plants won’t be able to bounce back from damping off, and so it’s up to the grower to prevent it from happening in the first place.

Pests and Bugs


Ants on Marijuana Plants
When Ants Affect Your Marijuana

Ants are something of a deceptive pest. They don’t directly threaten your cannabis plants, but they are a strong indicator of other issues which aren’t as easily noticeable.

Ants don’t eat your cannabis, instead they will be attracted to the area because of other pests like whiteflies or aphids.

If you see ants in your growing environment, make a thorough sweep of the area to see if there are any other pests damaging your cannabis.

Additionally, the way ants dig tunnels and mound up soil can damage root systems and make it difficult to get good nutrient and water circulation among the roots.

Surprisingly enough, one of the most innocuous ways for you to deal with ants is the application of cornmeal. Just spread it into the substrate.


Aphids on Marijuana Plants
Aphids on Cannabis

What are Aphids: tiny, pale, and one of the most irritating pests you will encounter. A big part of the problem is their small size. Aphids are very easy to miss.

They’ll cling to the undersides of the cannabis leaves, draining out nutrients and reproducing very quickly.

Indoors, in a controlled environment, aphids can ruin an entire growing operation with alarming speed. Outdoors, there are a number of natural predators which can help protect your plants.

As mentioned above, the presence of ants in your cannabis garden is one of the best ways to predict a possible aphid problem.

To get rid of aphids, there are a number of different options available. The best choice is usually an organically based spray that you can apply to the undersides of the foliage.


Birds on Marijuana Plants
Birds and Marijuana

These flying creatures are double-edged sword for most cannabis gardens. First of all, they’ll only be an issue with outdoor growing.

Outside, they actually do a great job of helping you to get rid of irritating and damaging pests. Birds subsist on caterpillars, worms, and a variety of other creepy-crawly critters.

The time you need to worry about birds is before your plants germinate.

Birds love seeds, and they can gobble up all of your cannabis before it even sprouts if you give them the opportunity.

There are a number of tried-and-true methods for helping to prevent birds from eating all of your seeds after you plant them.

You can use scarecrows or netting. Another method is to litter the area around your plants with shiny reflective objects.

Ideally, you should choose a method that is reversible, you can get the birds back after your plants have sprouted.

That way you can benefit from the positive aspects of the birds. Scarecrows are usually the easiest option, and often the most fun, besides.


Caterpillars on Marijuana Plants
Eating your Cannabis Plants

Caterpillars can be extremely hazardous to your cannabis crop.

They have a voracious appetite, and they often go unnoticed until they’ve already done significant damage to your foliage.

In particular, beware of the ‘borer’ varieties of caterpillars, which will burrow into the plants delicate interior and eat it from the inside out.

If you don’t pay close attention, your whole plant will be dead and hollow without you ever even knowing you have pest issues.

Unfortunately, even caterpillars that stay on the exterior of your plant can still ruin your crop.

Caterpillars are strongly attracted to cannabis, and they will actively seek it out as a food source.

Outdoors, you can get help from wasps and praying mantises, but there are number of organic deterrents you can use as well.

Cats and Dogs

Cats and Dogs on Marijuana Plants
Cats, Dogs and Marijuana

We love our pets, but anyone who owns cats or dogs knows very well that they can cause trouble.

For the most part, you probably don’t need to worry about pets eating your cannabis (although you never know what they’ll want to chew on).

The real issue is urine and defecation. Especially if you are using soil, there is a risk that your cat or dog will choose that spot to answer nature’s call.

While you might think ‘Hey, free fertilizer!’, you really don’t want pet urine or feces to mix with your crops.

Cat urine is extremely high in ammonia and can badly damage your plants

(besides the terrible smell). Plus, fecal matter from pets can attract parasites and pests that you don’t want crawling around.

In general, you’re better off keeping pets far away from your cannabis plants. They probably won’t help in the cultivation process.


Cutworms on Marijuana Plants
Cutworms on Cannabis

The most dangerous time for cutworms is when your cannabis plants are still seedlings. Cutworms can absolutely destroy seedlings, and worst of all, they’re sneaky.

They only come out and eat your plants under the cover of darkness, so it’s likely that you’ll never even see them in action.

If it looks like someone has been trimming the tops of your plants and it wasn’t you, look closely for cutworms.

Thankfully, it’s not too difficult to get rid of cutworms.

Like some of the other pests listed here, they have a number of natural predators, so sometimes they’ll just go away without any extra intervention.

Often, you can get rid of cutworms just by tilling the soil or planting sunflowers around the edges of your cannabis garden.

Tilling is a good reactive measure, will the sunflowers are preventative, allowing you to keep cutworms out until the plants are big enough that you don’t need to worry about cutworms.

Crickets and Grasshoppers

Crickets and Grasshoppers on Marijuana Plants
Grasshoppers and Crickets on Cannabis

Grasshoppers and crickets are common outdoor pests all over the world, and they have the potential to wreak havoc on your cannabis crop.

They have voracious appetites, and if you let them, they’ll make your cannabis plants the foundation of their diet.

There are a lot of different species of crickets and grasshoppers.

Most of them will eat your plants at night, under the cover of darkness, and so they can also be hard to find until after they’ve already done their damage.

Crickets and grasshoppers are pests that you almost certainly don’t want to leave alone.

They’re difficult to root out, but without intervention, the problem won’t disappear.

Even worse, birds and other predators have to dig up the soil to get at them, which can damage your root systems.

Your best bet for getting rid of them is to spray the area with a mixture of diluted dishwashing liquid.


Deer on Marijuana Plants
Keep Deer Out Of Your Cannabis

Deer eat plants. They are herbivores. Unfortunately for the cannabis grower, they don’t take exception to young succulent cannabis specimens.

On the plus side, once the cannabis matures, the strong odor won’t be attractive to most deer, and you don’t need to worry about them eating your crop.

Until your plants mature, though, deer can be a huge menace. Instead of just damaging the plant beyond repair, they will eat the whole thing, leaving only some ragged root systems behind.

The best option for you is a fence. A sturdy, properly constructed fence of adequate height will keep deer out of your garden, and chances are good that they will take their search for food elsewhere.

If you don’t have the resources or space to construct a fence, you have a few other slightly less effective options.

First, motion-detecting or flashing lights can scare off deer, who usually feed in the twilight of early morning or late evening.

Deer are also very sensitive to scent, and there are a variety of products on the market that can act as deterrents for deer. Some growers report success with garlic or moth balls.

Fungus gnats

Fungus Gnats on  Marijuana Plants
Marijuana with Fungus gnats

Fungus gnats aren’t quite as bad as they sound, but they’re far from harmless.

Like the other pests listed in this index, fungus gnats can cause a lot of damage to the stems and roots of your plants.

In both the microscopic larval and adult phases, fungus gnats love to eat cannabis.

They start out eating fungus at the base of the plant and then eat their way downwards into the root system.

Obviously, this is terrible for the plant: growth will slow, and the plant can become structurally unsound. The drainage of the soil will also be severely impacted.

Thankfully, even though the fungus gnats can be nigh impossible to spot, there is an easy method to check for them.

All you have to do is put out a sticky pad near the base of the cannabis plant to catch the larvae. This won’t totally fix the problem, but it’ll get a lot of them.

To finish up, mix a little bit of peroxide and water and apply that to the area where the fungus gnats are located.

Gophers and Moles

Gophers and Moles on Marijuana Plants
Gophers and Moles on Cannabis

These two underground rodents present some clear potential issues. Anytime you have a burrowing critter; you’ll run the risk of root damage.

Fortunately, most of the time, moles steer clear of cannabis root systems. They have no interest in plants.

In fact, moles can offer benefits to your cannabis: they’ll aerate the soil and eat any insects they can get their paws on. Gophers, on the other hand, are bad news.

Gophers will seek out the roots of your cannabis plant and eat them. Left unmolested, they’ll pull down whole plants into their tunnels.

You can deal with gophers in a lot of different ways.

If some gophers take up residence near your plants, you can try to encourage natural predators in the area, like owls or hawks.

You can deal with them humanely by applying garlic or castor oil to the area. As a last resort, you can always set traps for gophers.

Leaf Miners

Leaf Miners on Marijuana Plants
Marijuana with Leaf Miners

Just like the name sounds, leaf miners will dig through and ‘mine’ the tops of your cannabis leaves, damaging the cells and draining out vital nutrients.

The symptoms are usually very easy to recognize: white or brown streaks running along the tops of the leaves.

The adult leaf miner closely resembles a house-fly, but significantly worse for the health of your plants.

The larvae are planted under leaves, and after they hatch, they burrow into the interior.

Unfortunately, leaf miners are extremely difficult to get rid of. Pesticides are mostly ineffective against them, and the ones that do work aren’t safe to use on your plants:

they’re more harmful than helpful. The only thing to do is seek them out and squish them yourself.


Mealy Bugs on Marijuana Plants
Mealybugs on Cannabis

Mealy bugs are soft little bugs from the Pseudococcidae family. They live in the nooks and crannies of your cannabis plant.

If there aren’t a lot of them, they won’t actually have any negative effects, but beware of their population swelling out of control.

The clearest symptom of a mealy bug population is the occurrence of white, gauzy balls that the bugs weave. Some of the foliage might also begin to develop blotchy patches.

Curiously enough, one of the easiest ways to tell that you might be at risk for a mealy bug infestation is the presence of ants.

Ants offer protection for the mealy bugs by keeping the environment clear of other insect predators.

To get rid of mealy bugs, you can simply clean them off the plant by hand or use a natural product like lemon juice as a deterrent.

Rats and Mice

Rats and Mice on Marijuana Plants
Rats and Mice Love To Eat Your Marijuana Plants

These are the universal pests. Although they’re not specifically drawn to eat cannabis plants, they are omnivores and will eat your plants if they don’t have a better option available.

In the case of rats, they might just chew through the cannabis plant as a reflexive action to control their constantly growing incisors.

Both rats and mice are very wary of humans and have excellent senses. You might not see them, or be aware of their presence.

As with many of the pests listed in this index, your best bet is to take preventative rather than a reactive measure to keep rats and mice away.

That is; you should do your best create an environment which discourages them from being around.

Ideally, you’ll have some sort of other predators around to help with this, but you can always resort to traps.

Snails and Slugs

Snails and Slugs on Marijuana Plants
Snails and Slugs on Cannabis

If you grow cannabis outdoors, you’ve probably run into issues with snails and slugs before. They’re a common pest for cannabis growers.

They’ll leave those glistening trails of gloop everywhere, and usually they’re very noticeable because of it.

Snails and slugs both subsist on plant matter, and they will cause a lot of damage to the plant if you leave them alone.

The best way to deal with slugs and snails is to create an environment that is hospitable to amphibians: toads and frogs are natural predators.

You can do this by adding in ponds or water features near your plants.

If that’s too much trouble or just not an option at all, you can also apply salt to the area to make it inhospitable and dangerous for slugs.

Surprisingly enough, beer can also be used to help discourage slugs and snails from tromping around your cannabis garde

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Spider Mites

Spider Mites on Marijuana Plants
Spider Mites and Cannabis

The most common problem for cannabis growers is infestation by spider mites. They can create a huge hassle for your garden.

Spider mites reproduce extremely quickly, and they reach full maturity in less than a week.

This means it’s easy to be swiftly overrun by the tiny creatures in a short amount of time.

Spider mites feed on your plants, draining out valuable nutrients and chlorophyll until the plant dies.

Left to their own devices, spider mites will quickly ruin your entire cannabis crop.

Thankfully, there are a wide variety of different ways to treat spider mites, including a number of safe, natural remedies.

Ladybugs are ubiquitous to many parts of the world, and they are a fantastic predator for spider mites. Consider introducing them to the environment to deal with the problem.

Spider mites can also be sprayed with a mix of neem oil and water. This will knock them off the plant, and they can have difficulties getting back onto it.

Since their metabolism is so fast, they will die quickly without access to their food source.


Thrips on Marijuana Plants
Thrips on Cannabis

Although the thrip is a very small insect, they can create huge issues in your cannabis garden.

Their primary source of food is the flower itself, which means your plant won’t be able to properly mature, and you won’t get a good yield out of your plants.

Thrips are also known for spreading plant diseases, which can sometimes cause even more damage than the tiny insects themselves. In any case, thrips are bad news.

As with most pests, the best way to deal with thrips is preventative action. Stop them before they even get into your garden.

Using the highest quality compost and maintaining a clean environment for your plants is a good way to help you in this regard.

If you already have thrips infesting your plants, however, you’ll need to get rid of them. There are a number of predatory mites which you can introduce to the area.

This will help curb their population. Alternatively, you can spray them with a mix of neem oil and water. This will knock them off the plant and help protect your flowers.


Whiteflies on Marijuana Plants
Whiteflies on Cannabis

These little creatures live on the undersides of cannabis leaves and chew on the plant matter. They are flying insects, and they’re very small.

The biggest problem with whiteflies is the one-two punch combination of mobility and their high potential for spreading disease.

Like the thrip, whiteflies can spread diseases throughout your entire crop, ruining an otherwise great harvest.

As with the other pests we’ve talked about, your best bet is to prevent these sorts of infestations before they occur at all.

If the whiteflies never show up at all, you never have to worry about them spreading any diseases.

Again, pest management techniques usually start by creating an environment that is inhospitable to the pest itself.

The best way to accomplish this is by introducing and encouraging natural predators.

For example, planting zinnias or other colorful flowers will help attract hummingbirds and insects which can prey on the whiteflies.

You can also create diluted garlic mixes to help discourage the whiteflies.

Environmental stresses

Plants won’t Flower- Dark cycle interruption

Dark Cycle Interruptions Marijuana Plants
Dark cycle interruptions marijuana plants

Plants are extremely sensitive to changes in light. That’s how they grow, and how they know that seasons are changing.

Changes in the intensity and schedule of light exposure will radically affect the growth of the plant.

Outdoors, your plants will get all the sunlight they need for natural seasonal changes, but indoors you need to carefully manage all of the lighting to make sure the plants are growing well.

If you’re growing indoors, you can’t rely on the plant to ‘know’ when it should be flowering and maturing. You have to help it more than you would a plant that’s being grown outside.

Before flowering begins, every cannabis plant needs to undergo a period of uninterrupted, total darkness.

Every strain is slightly different in this regard, but be absolutely sure that the plant isn’t getting any light during this crucial period, or it won’t flower properly.

Humidity and Temperature

Humidity and Temperature in your Marijuana Grow Room
Temperature & Humidity Controllers

Cannabis is an unusually hardy plant, and it can survive in a wide variety of conditions, but that doesn’t mean it will thrive in less than optimal conditions.

If your grow room is too hot or too humid, it’s quite likely that your plant will become stressed, and they won’t grow to their full potential.

If there is too much humidity, you can simply invest in a dehumidifier. It uses electricity, but it will replace the moist air with drier air. All you need to do is empty the reservoir regularly.

When it comes to temperature, cannabis plants like it hot, but there is a point at which it can become too hot.

Anything over 80 degrees Fahrenheit is likely to be less than beneficial for most varieties.

If your grow room is too hot, you can use air conditioners to help cool it down.

Alternatively, you can cycle cool water through the root systems to allow the plant to cool itself.

Pruning Cannabis

Pruning Cannabis Plants
Pruning Marijuana Pllants

It can be beneficial to the overall health of your plant if it’s done right.

Farmers frequently prune plants so that they can get a better harvest out of an individual plant.

Done properly, pruning will help you maximize your yield, but it is absolutely essential that you know what you’re doing if you start pruning.

If you aren’t sure about what to do, you’re much better off not pruning at all.

If you prune your plant excessively, it won’t be able to produce as much energy, and so it won’t produce as many buds in the long run, and those buds that are produced will be smaller. Pruning is usually done with leaves that are already dead, or leaves that are blocking out a lot of light.

Airy and loose buds

Airy and Loose Cannabis Buds
Airy And Loose Marijuana Buds

These are usually considered to be of lower quality than the tight firm buds that smokers favor.

The looseness of the buds can be caused by a wide array of environmental factors, ranging from too little light or nutrients to too much heat.

For most growers, a high temperature is the guilty party.

If your grow room is getting you loose buds, consider adding an air conditioner to your setup to help cool the room.

You can also experiment with moving the plants around so that your room is better ventilated.

Growing outdoors? you can help ameliorate loose buds by using a micro-sprayer system.

If your plants don’t get enough potassium during the flowering process, you can also get loose, airy buds. If you think that might be the case, simply switch to a fertilizer that gives you a higher concentration of potassium.

Clones won’t root

Cannabis Clones wont Root
Marijuana Clones

Another problem growers can experience is stretching in their cannabis seedlings and plants.

Usually, these long spindly plants stretched out because of a number of environmental factors, often light-related.

Stretched cannabis plants are unable to support proper branches, leaves, and buds.

The stems are just too thin. Keep an eye on your plants to make sure this isn’t happening to you!

If the stems aren’t developing enough, you can gently bend the stem back and forth.

While this might seem counterintuitive, damaging the plant, a little bit will force it to devote some energy to strengthening and re-growing the stem.

You can also solve this issue by adjusting the spectrum of the light you’re using, and making sure that the temperature is hot without being overly hot.

Make sure the plants are getting plenty of light, or the plant will stretch out in an attempt to reach the lights.

Stretching plants

Stretching Cannabis Plants
Stretching Marijuana Plants

Another problem growers can experience is stretching in their cannabis seedlings and plants.

Usually, these long spindly plants stretched out because of a number of environmental factors, often light-related.

Stretched cannabis plants are unable to support proper branches, leaves, and buds. The stems are just too thin.

Keep an eye on your plants to make sure this isn’t happening to you! If the stems aren’t developing enough, you can gently bend the stem back and forth.

While this might seem counterintuitive, damaging the plant, a little bit will force it to devote some energy to strengthening and re-growing the stem.

You can also solve this issue by adjusting the spectrum of the light you’re using, and making sure that the temperature is hot without being overly hot.

Make sure the plants are getting plenty of light, or the plant will stretch out in an attempt to reach the lights.

Heat stress

Marijuana Leaf Problems
Marijuana Heat stress

If your plant is exposed to unusually high or low temperatures, that can stress your plant in a number of different ways.

Ideally, you should keep the environment close to 80 degrees Fahrenheit, but it will do well near this as long as it isn’t too hot.

The temperature can drop up to 15 degrees during periods of darkness if necessary, but be careful. Temperatures that drop too low end up slowing the growth of the plant significantly.

When it comes time to harvest the buds, you’ll notice a decreased yield to go along with the slow growth.

Unfortunately, you won’t notice this until it’s too late. So do yourself a favor and make sure that your grow room is hot enough! Keeping a close eye on the environment is key.

The flip side is making sure that your grow room doesn’t get too hot.

If the temperatures are too hot, the plants can be damaged.

You might experience weak stalks and stems, as well as wilting droopy plants.

Consider your ventilation in too-hot grow rooms, and possibly adding an air conditioner if you’ve already run out of other options in how to adjust the ventilation in your plant’s environment.


Hermaphrodite Cannabis Plants
Marijuana Hermaphrodites

Hermaphroditism is not a good trait for growers of indoor cannabis.

The problem is that if the plants possess both genders, they can pollinate themselves and the other plants around them.

One single hermaphrodite plant can pollinate an entire grow room.

Unfortunately, pollinated plants produce much lower quality buds, and the smoke is undesirable by most medicinal and recreational users.

While stress can theoretically cause hermaphroditism in cannabis plants, it’s usually predetermined by the plant’s genetics.

Remember to avoid any major stresses that can induce the plant to become hermaphrodite.

For example, it’s possible for your plants to grow just fine outdoors, but if you move them indoors, the stress can cause them to produce male flowers and exhibit traits of both plant genders.

If this happens, your only option is to quickly try and pick off the male flowers so that the plant doesn’t self-pollinate.

You’ll also want to separate it from the rest of your growing operation so there’s no risk of pollination there either.

Also, try not to use seeds from hermaphroditic plants, because every subsequent generation will run the risk of self-pollination.

Seeds won’t germinate

Marijuana Seeds wont Germinate
Marijuana Seeds

Sometimes cannabis growers will have a huge issue at the beginning of their cultivation.

The first issue you can have is seeds that just won’t germinate. There are a number of factors that can influence a seed’s inability to germinate.

Usually, a seed should just need water and a warm environment, but if you’re having trouble, you can try soaking the seeds in a heavily diluted solution of hydrogen peroxide and water.

This will weaken the seeds outer coating and make it easier for the seedling to pop out. Also, seeds don’t last forever.

If your seeds are too old, they might never germinate, and you’ll have to throw them away.

Knocked down plant

Cannabis Plant Knocked down
Marijuana Knocked down

Cannabis plants are tall and thin, and sometimes they can be knocked over by storms or unusually heavy winds.

But remember, cannabis plants are hardy! If your plant gets knocked down, it might still be able to survive.

You should get the plant back into position as soon as possible and repair any of the breaking that might have damaged the stem.

Make sure that the plant is firmly rooted and stabilized against any future winds.

Stakes can help you support a plant, much like a brace or cast helps support a broken leg. You can use tape to help repair breaks in the stem, as a sort of bandage.

If the roots are ripped out of the soil, you need to make sure you get them covered back up.

Roots don’t deal with exposure to light and air, and if the roots aren’t pulling in water and nutrients from the soil, the plant will die.

Hard and Soft water

Hard or Soft Water for Marijuana Plants
Hard and Soft water on Marijuana Plants

Outdoor growers of cannabis don’t have the same luxuries as indoor growers. Inevitably, you’ll have to deal with unpredictable weather.

Extreme cold, long periods without rain, and periods of heavy rain can all cause issues for your crop.

If your plants are cold, they’ll stop growing, and if they stop growing for too long, they can die.

Make sure to bring them indoors if the weather becomes inhospitable for a long time.

Excessively rainy or humid weather also causes issues.

Foremost, they will leave plants extremely vulnerable to fungus and mold, so try to make sure your plants get dry and warm after periods of cold rain.

Of course, storms can also cause direct physical damage to your plants. There’s little you can do about this if you are growing your plants outdoors.

The Weather

Cannabis and Weather
Marijuana on Winter Weather

Outdoor growers of cannabis don’t have the same luxuries as indoor growers.

Inevitably, you’ll have to deal with unpredictable weather. Extreme cold, long periods without rain, and periods of heavy rain can all cause issues for your crop.

If your plants are cold, they’ll stop growing, and if they stop growing for too long, they can die.

Make sure to bring them indoors if the weather becomes inhospitable for a long time.

Excessively rainy or humid weather also causes issues.

Foremost, they will leave plants extremely vulnerable to fungus and mold, so try to make sure your plants get dry and warm after periods of cold rain.

Of course, storms can also cause direct physical damage to your plants. There’s little you can do about this if you are growing your plants outdoors.

Overwatering and Underwatering

Overwatering and Underwatering Cannabis Plants
Overwatering and Underwatering Marijuana Plants

When and how much to water your plants? This is practically an art.

Your plants need change during different stages of development and depending on other environmental factors.

You can’t let your plants go for too long without water, but if they don’t get enough, they will wilt and become unhealthy.

Don’t ever wait until the plants start to become limp before you water them.

The easiest way to see if the plants are getting enough water is to check the substrate or soil the plant is growing in.

It should be moist without being wet or saturated. If the soil is too dry, then water it.

Too much water can also cause issues for your plant. If the roots of the plant don’t get enough oxygen, the plant can drown.

Make sure the soil around the roots is properly aerated, and that the plants drain well.

Soil Problems

Cannabis Soil Problems
Marijuana soil problems

Soil is the frame for your plant. If you’re growing outdoors, you can find a huge variety of different types of soil, depending on your location.

Many places don’t have soil that is good to work with for growers, so check on the soil quality near you before starting up your growing operation.

Clay soils have poor drainage, for example, and this can cause your plants to drown from overwatering.

Sandy soils often drain too well, and the plants won’t get enough water or nutrients. Dried-out soil often needs to be treated, mixed up, and moistened for it to work well.

All of these different issues can be fixed by adding different soil types into the mix and balancing out the environment.