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Disease Guide – Verticillium Wilt

Verticillium Wilt and Cannabis Plants

When marijuana plants are put in the ground, the grower’s intention is for them to take root and thrive. However, if verticillium wilt fungi are present, issues and disease may occur. This condition is often seen in soil that’s overly rich or that doesn’t drain properly.

It’s important to monitor all indica weed and sativa weed plants, as those most likely to develop this condition are ones with stressed roots. Keep reading to learn how to recognize and treat verticillium wilt.

Understanding there is a problem is the best way to take action and prevent it from affecting even more of your cannabis yield.

An In-Depth Look at Verticillium Wilt

Verticillium wilt is a fungus. It targets the roots of a plant and moves up the vascular system, moving through the xylem.

Here is some basic plant biology. The xylem transports water out of the ground, through the roots, up the plant’s stalk, and finally into the leaves.

If the verticillium fungi make it into the xylem, it will block the vessels that let water enter the plant and create toxins that spread through the entire plant. This causes the plant to yellow, wilt, and eventually die.

It’s important to note that verticillium wilt isn’t exclusive to marijuana plants. It may occur in an array of plants, such as sunflowers, cotton, alfalfa, tomatoes, hops, potatoes, pumpkins, peppers, strawberries, peppermint, melons, eggplants, and more. Some agriculture professionals will fumigate the soil before they plant the crops. This helps to prevent the development of verticillium wilt. This fumigation is done using costly chemicals that kill any fungus in the soil; however, they are also toxic to the environment and the health of people. This is one reason experts have stressed the importance of purchasing organic produce.

Verticillium wilt fungi can remain alive in the soil for many years. It’s not uncommon for the fungus to develop in soil that doesn’t drain properly or that is too rich in nutrients. Usually, it will thrive in areas that are humid and that stay at a temperature between 68- and 82-degrees Fahrenheit. This disease is common in the Pacific Northwest region of the U.S. but can occur in other parts of the world, too. It tends to show signs during the fall or spring when warm and humid conditions exist.

Top Signs of Verticillium Wilt

It’s essential to note any changes that appear with the marijuana plants. There are specific signs a grower will see when their plants begin to be affected by Verticillium wilt. For example, the leaves near the base of the plant may change color, appearing more yellow than green. Specifically, this will occur between the veins on the leaves and the outside margins.

If this change in color is noticed, it is a good sign that verticillium wilt has affected your gorilla glue or skywalker ghost plant. Eventually, the leaves will turn a brownish-gray color, and the plant will start to wilt. The stem of the marijuana plant will start to brown near the base, very close to the soil line.

If a grower is aware of the symptoms of Fusarium wilt, they also know the common symptoms of Verticillium wilt, as they are similar. As soon as the condition makes it into the plant’s root system, the xylem vessels will begin to clog, which means the plant cannot take nutrients and water in through the leaves and stem.

Getting Rid of Verticillium Wilt

As with any condition that may affect a marijuana plant, prevention is key. One of the best ways to prevent several ailments that may affect these plants is to amend your soil with compost that has been properly aged.

Another effective way to prevent this condition is by using a hydroponic growing system for the plants. However, if a grower has committed to using soil, compost is the best option. It’s important to be certain the compost is properly sterilized in the sun. If sterilized and cured correctly, compost is an effective and natural way to give plants the support needed to not only grow but thrive.

Along with compost, having proper draining for the soil is crucial to eliminate the possibility of Verticillium wilt. When too much moisture is present, the root systems are much more likely to be plagued by this problem. Ensuring proper drainage offers a smart solution to minimize the likelihood marijuana plants will develop Verticillium wilt.

It’s also possible to prevent this infection by deep plowing the grow site before planting or transplanting the seedlings, or by practicing crop rotation. After the area is plowed, be sure to add some sterilized compost mentioned above.

If a grower notices signs of Verticillium wilt, they should act right away. Remove all plant matter affected by this disease. However, as this is done, be sure to be careful. The spores can travel to nearby plants. If the symptoms are seen early enough, it is possible to eliminate the problem before it affects the entire crop.

Common Symptoms of Verticillium Wilt on Marijuana Plants

When Verticillium wilt appears, it will show several symptoms on the marijuana plants. Some symptoms that will appear on the leaves include:

Gray-brown coloring

Yellowing of the outer margins

Yellowing between the veins

Some symptoms that will appear on the plants include:

Browning of the stem near the soil line


Clogging of the xylem root vessels

Right now, the only way to deal with Verticillium wilt is prevention. At this time, there is no way to control it once it develops or a way to heal the plants affected. Also, once established, Verticillium may remain in the soil for many years, which means any infected fields won’t be suitable for any type of plant growth.

Remember, if a grower has plants with strong genetics, there is a much lower chance of the plants getting sick or being affected by pests. That’s why it is so important that seeds are purchased from a trusted seed bank.

Tips for Preventing Verticillium Wilt on Marijuana Plants

As mentioned above, to avoid having to deal with Verticillium wilt, a grower must take preventative measures with their soil and use certain best practices for growing the plants in the soil. Some best practices to follow when attempting to prevent Verticillium wilt are listed here.

Grow the Plants in High-Quality Soil

Since Verticillium wilt can remain in the soil for years, it is essential to only use potting soil for cannabis plants that a grower knows is free from this disease. Buying sterilized compost is one way to ensure no fungus is present. It’s also important to avoid working with soil a grower knows is infected with the fungus.

If the fungus takes hold your blueberry ice weed plants, make sure to dispose of them and don’t add them to the compost pile. This will only cause the disease to spread the next time something is planted. Unfortunately you will have to scrap these and start a new batch of weed growing seeds.

Another solution is to plant cannabis in containers, rather than directly in the ground. This is especially important if a grower is working land they have never farmed before. This helps eliminate the unknown issues that may be in the soil.

Be Sure the Plants Have Proper Drainage

It’s important to avoid overwatering the plants and mix plenty of organic matter into the soil to make sure proper drainage is present. Remember, Verticillium fungus thrives in wet, warm environments, so if the soil has too much moisture, it is a red flag.

It’s a good idea to test the soil drainage before planting the cannabis plants. When searching for good areas for growing cannabis, remember, the water needs to move downhill. If the growing area is flat, a French drain is a viable solution. This is a small trench that has a downhill grade of one to three percent, which is filled with rocks. If there is water that pools in the garden, the drain will help ensure it flows downhill.

Use Deep Plowing, Crop Rotation, and Solarize the Soil

For a seasoned outdoor seed grower who is committed to planting their cannabis crop right into the ground, there are a few farming best practices that can reduce the likelihood that verticillium will occur. Till the soil deeply and use a fungus-free, sterilized compost. Solarizing the soil is also a good move. This is done by tilling the soil, mixing in the compost, getting it wet, and then covering it with a clear plastic layer for up to three weeks.

Crop rotation is also beneficial. This helps to prevent other diseases from affecting the plants. If verticillium wilt affected the land, it’s a good idea to plant a cover crop that’s resistant to this fungus. When it is time to plant again, till over the cover crop and into the soil. Some of the best options for cover crops that verticillium resistant include broccoli, mustard, and sudangrass.

The Bottom Line

Growers can also try to prevent the development of Verticillium wilt by choosing plants with strong genetics and to ditch the soil altogether and use hydroponics for growing the cannabis plants. If you choose to go the soil route be sure to follow the advice above to ensure that your cannabis crop is Verticillium wilt free! Be sure to check out regular clearance page for special deals on popular strains like grandaddy purp and feminized white widow. As always, the cannabis grow guide has your back for any problems you may experience through the course of your grow.