How To Prevent Verticillium In Your Cannabis Crop

Perhaps one of the greatest skills a cannabis grower can boast is that of vigilance. Outdoor growers face a truly vast array of possible threats when it comes to pests, infestations, and diseases. Keeping an eye out for the onset and doing everything possible to prevent such occurrences is optimal, as certain conditions have no cure and can render an entire crop worthless.

Verticillium wilt is one such devastating disease. It is caused by the occurrence of fungi within the soil, primarily due to soil that is extremely rich in nutrients, or soil that does not drain correctly and collects too much water.

The fungi reside within the soil for periods of up to many years. Eventually, they germinate and start to attack the roots of plants that are susceptible to the condition. Here, they proliferate into a transport system within the roots known as the xylem. The xylem is responsible for transporting water through plants, from the roots up to the leaves.

When fungus enters the xylem, its growth causes a blockage of these vessels, which results in the obstruction of vital water. It also begins to produce toxins that travel up the xylem and into other areas of a plant.

SIGNS OF VERTICILLIUM WILT

Although the condition does not yet have a cure, it is of paramount importance to keep a watchful eye for the signs and symptoms of the fungal disease. This will ensure that, if confirmed, growers can deal with the problem immediately.

This will unfortunately involve removing and destroying all affected plants, and even abandoning the spot of soil for some time afterwards. Some reports state that the area should be grassed over for a period of 15 years, or be planted with species that are known to be resistant to the condition.

Verticillium wilt causes some pretty tell-tale signs, including the following symptoms:

• Yellowing of lower leaves
• Shrivelling of lower leaves
• Parts of a plant, or the entire plant, suddenly begin to wilt; exacerbated by hot, humid conditions
• Branch dieback; sometimes only several parts of a plant will be affected
• Browning of the stem around the soil line

TACKLING VERTICILLIUM WILT

As stated above, verticillium wilt is a rather brutal condition, and once it has set in, it’s time to start ripping out plants and trying to prevent the spread of the infection. If one of your plants falls prey to it, remove the specimen and as much of its root system as you possibly can. Be sure not to spread the soil into the surrounding area and to other parts of the garden, where it can spread and start to do similar damage to other portions of your prized crop.

Because poor soil drainage is reported to be a contributing risk factor to verticillium wilt, it is important to ensure adequate drainage, which can be achieved in numerous ways. Because these fungi linger near roots, adequate drainage may help to keep the soil clear of any unwanted guests.

One way to improve soil drainage is to add more organic matter to the mix; this will help to create space and allow for more water to flow out of the soil. Constructing a raised garden bed is another good option when it comes to soil drainage. In a raised bed, the soil is elevated above the surrounding ground, allowing water to run off well. Raised beds also come with a whole other host of benefits that make them a worthwhile installment, such as increased root health and general ease of access.

BACK-UP PLANS

If your garden has been hit pretty hard by this condition, then there are other options for growing cannabis. If you think your soil is contaminated (and you have the finances to invest), you could always elect to use a hydroponics system instead.

Hydroponic systems use no soil at all; instead, plants grow in a medium usually made up of clay pebbles, coco coir, or something similar. The roots grow down from the medium into a water reservoir below, where they uptake nutrients that have been added exclusively by the cultivator.