Why Do I See Holes on My Cannabis Plants?

A garden is a rich ecosystem full of various insects, bacteria, plants, and even some birds. However, sometimes, uninvited guests show up, and they can wreak havoc on your previous cannabis plants. 

If you have noticed any weird holes in your cannabis plant, it is probably one of the uninvited guests making themselves at home. 

You must eliminate them from your garden before they damage your plant further. While the damage may look minor initally, it can eventually stunt your plant's growth and even kill them.

In this article, we will show you how to identify and eliminate these pests that make holes in your plants. Note that this article is mainly focused on outdoor pests since you tend to see many more pests when growing marijuana outdoors. 

1. Caterpillars

Caterpillars are colorful, cute creatures, but don't let their looks deceive you. They are your nemesis if you're a cannabis grower.

Caterpillars are the larval stage of butterfly and moth species, and there are over 175,000 different species of them in the world. They range from 1 mm to 14 cm and are primarily herbivorous, except for some species.

Unlike other larval species, you can tell caterpillars apart by their appearance. They have five pairs of legs, crochets on the prolegs, twelve eyes, and a Y or V-shaped cleavage lines on the front.

Look at them with naked eyes, and you will see them strolling about the garden, but look a little closer, and you'll get a glimpse into their fascinating lives. They have their own chemical-based defense mechanisms, social behaviors where they form alliances with ants, and a lot more.

However, they are bad for your plants as they can do a lot of damage. They leave tiny holes scattered around the plant, especially on the fan leaves, and a lot of them can lead to fatal problems for your plant. 

Fortunately, only a few caterpillar species are destructive to your plants, like the cabbage looper. These species graze on the leaf surfaces, stripping away the pieces of the tender tissue. And some other species feed on the stems, too.

So, you must be on the lookout for them and eliminate them quickly.

Spotting Caterpillars on Cannabis

Caterpillar damage on cannabis ranges from a few spots here and there to a total loss of yield and a dead plant. But there are signs you can look for before it's too late, such as the following.

• Irregular Holes Around the Plant

Caterpillars love eating leaves, and they are not neat about it. So, they tend to leave oddly shaped holes in the leaves, ranging from a few millimeters to centimeters. However, holes are holes, and it doesn't matter whether they are messy or neat. 

• Damage to the Stem

Another sign of caterpillar damage is the stem showing damage. This is done by species like the Eurasian hemp borer that love feasting on the stem's dense tissues. Essentially, they bore a hole in the stem and tear through the interior tissue, which can lead to various issues like weakened structure, nutrient deficiency in the adjoining branches, etc.

• Chewed Out Flowers

Some burrow species also love feasting on the buds' resins and phytochemicals. So, they burrow into the flowers and rush to the base, which results in the buds wilting and dying off.

• Yellowed Leaves

Due to borrowing in the stems, caterpillars can hamper nutrient and water transportation within the plant, leading to the leaves turning yellow and wilting due to deficiency.

• Stunted Growth

Due to a lack of nutrients and water supply, the plant struggles with photosynthesis. Ultimately, the plant may experience stunted growth and may die off. 

Getting Rid of Caterpillars

Fortunately, caterpillars are pretty easy to get rid of. There are various ways of getting rid of them without using strong chemical-based pesticides. Instead, you can try other safer alternatives such as the following:

• Physically Pick Them Out

Caterpillars are not tiny — they are visible to the naked eye. So, if you have a few caterpillars strolling about your garden, you can pick them up and relocate them. Remember that they are nocturnal, so the best time to spot them is during the night.

• Use Parasitic Wasps 

If you don't want to take the effort of finding them, you can get someone else to do it for you. For example, you can use parasitic wasps that hunt down caterpillars and use their bodies to lay eggs. They are pretty effective at eliminating caterpillars in your garden.

• Use Praying Mantis

If wasps scare you, you can use praying mantis — also known as the masters of stealth! They wait under the leaves or behind the stem until they spot a caterpillar and then assassinate them swiftly.

• Try Bacteria Sprays

Bacteria sprays are natural pesticides that you can use to kill caterpillars without harming your plant or the environment. These sprays contain Bacillus thuringiensis bacteria that kill caterpillars in no time. And you can get these at your nearest horticultural store.

Preventing Caterpillars

Like your family doctor says, prevention is better than cure. The same applies to protecting your plant from caterpillars. Use the following methods to prevent caterpillars from coming back to your garden.

• Use Beneficial Insects

You can harbor various predatory insects in your garden as a preventative measure against caterpillars. They patrol the garden and kill any caterpillar that strays into their territory.

• Put Up Barrier Fabrics

Caterpillars usually crawl into your plant, so you can stop them from entering using barrier fabrics. Sure, they don't look pretty, but they do the trick at warding off various pests. You can use a simple wooden frame to prop up the fabric around your plants. 

• Spray Neem Oil

Lastly, you can regularly spray your plant with neem oil. It is a natural pesticide that contains phytochemicals that repel caterpillars. 

2. Crickets

Like caterpillars, crickets also love cannabis. And while many love their chirps, you don't want them chirping in your garden as they are a threat to your cannabis plant.

They feast on the plant and seedlings, and it won't be long before they end up destroying your plants and compromising your yield. So the moment you hear their chirps, it's time to act and eliminate them.

Crickets are nocturnal, with a body of 1 to 2 inches, and they come in yellow, white, green, brown, black, or red colors. They have two antennas on their head, wings that lay flat on them, and three pairs of legs.

Spotting Crickets

Spotting crickets is also relatively straightforward. In most cases, you will hear their chirps at night — that's the first sign they are present in your garden. Another common sign of cricket infestation is brown spots or holes in your plants.

They also tend to form tunnels in the soil as some species like to burrow underground, like mole crickets. They affect the root zone and invite other animals and birds that love eating them. Usually, they dig into the soil to find their tasty snack and destroy the root zone entirely.

Getting Rid of Crickets

Wait before you go on a rampage — some crickets are good for your garden. For example, some crickets eat harmful weeds (not cannabis) and other pests like aphids. In addition, they decompose dead plant material into humus for the soil, and their feces act as manure. 

However, if you spot crickets in a large number harming your plant, it's time to act. 

• Catch Them Manually

The easiest way to get rid of crickets is to pick them up and relocate them to another garden.

• Set Up Traps

If there are too many of them, you can set up a trap for them. Usually, the molasses trap is the most effective as the sweet smell attracts the crickets and later drowns them.

Mix a cup of molasses into 2 liters of water and place it near your plant. 

• Use Pesticides

You can even use pesticides to kill them quickly. Opt for these when other methods fail and stick to organic solutions as they are safe for the plant and generally don't affect the buds' flavor and aroma. 

Use pesticides, including boric acid, pyrethrin, spinosad, or diatomaceous earth. You can even use homemade pesticides like insecticidal soap, vinegar, garlic, essential oils, or spicy pepper.

Avoid using them if your plant is flowering because some can still hamper the buds' flavor and aroma.

• Get Help from Predators

There's always a bigger fish — or, in this case, bigger predators than crickets. So introduce frogs, rats, beetles, salamanders, or lizards into your garden. They love feasting on crickets, and they will help you get rid of them quickly.

Preventing Crickets

You have gotten rid of the crickets, but you must ensure they don't return. Use the following methods to prevent crickets:

• Inspect the plants regularly and remove any eggs 
• Get rid of dead or affected leaves
• Use bug lights that deter crickets 
• Dispose of any trash or dead plant material that may attract them
• If you are growing cannabis indoors, seal any entry points and ensure proper ventilation 
• Grow other plants like cilantro, rosemary, garlic, or beans — they deter crickets with their aroma and nitrogen

3. Grasshoppers

Grasshoppers are quite similar to crickets, and they too love eating tender cannabis tissues. They are the oldest living species of herbivorous insects, and they can cause severe damage to your plants — they can even wipe out your entire crop in no time.

They usually eat the fan leaves and juicy stems of the cannabis plant. They tear off chunks of the plant tissue, affecting the plant's ability to transport nutrients and carry out photosynthesis, leading to stunted growth or loss of yield in cannabis.

Spotting Grasshoppers 

You can spot grasshoppers with your naked eyes, but their camouflage may help them hide better. So, look out for other signs, such as the following.

• Dirt Mounds

Some grasshopper species like to dig holes into the soil, creating volcano-type mounds on the surface. These grasshoppers can damage the soil surface and roots of the plant.

• Holes on the Leaves and Stems

Other grasshopper species like to suck onto stems and leaves, leaving puncture marks or holes on the surface. This can lead to loss of photosynthesis and lack of nutrient transport in the plants.

• Brown Leaves

A major grasshopper infestation can put your plant under stress and shock, leading to the leaves turning brown. 

• Other Wildlife Presence

Lastly, grasshoppers attract other wildlife species that love to hunt them, like foxes, rats, birds, etc. If you spot these species rambling through your garden, there is a high chance they are looking for grasshoppers.

Treating Grasshopper Infestation

If you have spotted grasshoppers in your garden, you can get rid of them in two ways, as discussed below.

• Use Pesticides

You can use pesticides like neem oil to eliminate the grasshoppers from your garden. These pesticides will also kill the eggs and drive away any other invading pests.

Again, avoid using pesticides on your plant when it's in the flowering stage or close to harvest.

• Use Natural Predators

Two predators that love preying on grasshoppers but are otherwise completely safe for you and your cannabis plants are spiders and mantids (mantis).

To introduce spiders in your garden, create a thick mulch on the soil, which acts as a home for the spiders. The spiders will then hunt grasshoppers. The mulch will also help your soil retain moisture and protect it from harsh light while promoting microbes' life underneath.

And to invite mantids, plant shrubs like lavender near your cannabis plant. Mantids like to live around such shrubs.

Birds also love eating grasshoppers, so you can even keep some grains and a cup of water to invite them. 

Preventing Grasshoppers

And it would help if you prevented them from coming back. For this, you can use the following tactics.

• Set-Up Row Covers

Use row covers to protect the soil bed, where grasshoppers tend to enter from. Row covers are fine nets that allow light, water, and air while barring pests from getting onto the soil.

• Take Care of the Soil

Similarly, you also need to take care of the soil by keeping it clean. So, remove all the weeds and dead plant material. Doing so would prevent grasshoppers and invite other beneficial insects that will help your plant thrive.

• Grow Companion Plants

We all need friends — so does your cannabis plant. So, you can grow other plants like chamomile, basil, dill, and lavender, which will provide a home for mantids and spiders while driving away grasshoppers with their aroma. 

Don't worry — these plants aren't a complete waste. You can use them to garnish your dishes and herbal teas! THC-infused lavender tea does sound enticing.

• Host Fowl and Guinea Hens

Fowl and guinea hens especially love grasshoppers for their protein content. So, they go out of their way to hunt them without harming your garden. Plus, you can feed them waste food and garden waste and use their droppings as fertilizers.

• Sprinkle All-Purpose Flour

Grasshoppers eat whatever they can get their hands on, so they will eat the flour. However, that will be a fatal mistake as it kills them quickly. So, sprinkling all-purpose flour around your garden will kill any intruding grasshoppers quickly.

4. Slugs and Snails

Slugs and snails are a sign of trouble — they are less common, but many growers report their presence on online forums. 

These slimy creatures move slowly but devour a lot of plant tissue. As a result, they can quickly damage your plant by eating the leaves. They can also do more damage and create a deficiency in your plant.

Fortunately, they are easy to spot and remove. Also, they can't run or fly! 

Spotting Slugs and Snails

There are three ways you can spot slugs and snails on your plant. 

The first is quite simple — you will see them crawling slowly on your plant or around the soil.

The second sign is slimy trails on the leaves, grass, or the patio, which glisten in the sun. 

The third sign is more concerning — holes on the leaves. Slugs and snails eat the leaves irregularly, leaving scalloped edges around the holes. However, over time, these holes smooth out as the damage increases. 

Getting Rid of Slugs and Snails

You can get rid of slugs and snails in four ways, such as the following.

• Hunt Them Down

The first is the easiest but quite gross — hunt them down. The best time to hunt is during twilight. Use a torch and explore your garden. Check under the leaves, deep grass, stem, etc., for them.

Place them in a container and relocate them to a nearby pond or vegetation if you spot snails and slugs.

• Bring Natural Predators

Slugs and snails are tasty snacks for various predators, like hedgehogs, birds, toads, and newts.

So, you can bring any of these predators into your garden by creating a small open space and a small pond. Once they come, they will quickly start hunting down slugs and snails without disturbing your cannabis plants.

• Introduce Nematodes in the Soil

Nematodes are microorganisms that act as a parasite for slugs and snails. They enter their bodies and release toxic bacteria that kill the slugs and snails. 

But don't worry, they are a type of roundworm that is entirely harmless to humans and other warm-blooded animals. In addition, they offer various benefits: they protect the plants against fungus gnats, cutworms, fleas, and stem borers. 

You can purchase them from your local gardening supply store in the form of clay, sponge, or gel and apply them directly to the soil. Remember, they thrive the most in moist soil — the water gives them enough room to move about and find slugs and snails.

• Set Up Traps

Lastly, you can set up traps that lure and kill the slugs and snails in your garden. One of the most effective traps is using beer.

Sink a glass into the soil near your plant and fill it halfway with beer. They cannot resist the smell of beer (like many of us) and will enter the container, and the beer will drown and kill them. Talk about alcohol poisoning.

Preventing Slugs and Snails

Slugs and snails aren't the most intelligent creatures, so it's easy to prevent them from entering your garden. Here are a couple of ways you can deter them.

• Set Up Decoys

Near the entry points to your garden, set up decoy hiding places where they will go and hide. You can use broken plant pots, decoy plants, or bricks with holes. Check them every few days and remove them when you spot slugs or snails creeping around.

• Set Up Barriers

Or you can use moisture-absorbing minerals or repelling gels from your local gardening supply store to ward them off.

Summary: Why Do I See Holes on My Cannabis Plants?

If you notice any holes in your cannabis plant, you need to act quickly. The solutions are easy, but these pests can significantly damage your plant and affect your yield if you wait too long. 

In addition, if you see tiny holes, it may be due to spider mites, but you may need a magnifying glass to identify them. 

As soon as you spot holes, it would help if you looked for clues. It may either be slugs, grasshoppers, or caterpillars. Once you spot them, use the correct methods to eliminate them.

The easiest method to remove them is simply picking them up and relocating them. If that does not work, you can set up traps or bring in their natural predators. Although, before inviting any predators, ensure they are safe for your plants — a quick search on the internet or your local grower community can help.

And if nothing works, you can use pesticides. Whichever pesticide you use, ensure it is safe for your plant and won't hamper the taste and aroma of the buds. Even organic pesticides may be too harsh for the plant, so discuss with other growers to find the safest pesticide for your plant and use that.

Lastly, work up various ways of avoiding them. Traps, barriers, and natural predators are your best bet if you want to prevent pests on your cannabis plant. 

Stay tuned to know more about protecting your cannabis plants from intruders.