Root rot is a common problem for cannabis growers, and gardeners of all kinds. Luckily, root rot can easily be reversed, and even prevented, if the right steps are taken. But fail to act on your plant’s root rot and it may die.
Root rot is either caused by overwatering your plant, which starves your plant’s roots of oxygen, or due to a harmful fungus in your soil. This harmful fungus also prays on overwatered roots.
How to identify root rot:
Root rot can be identified by the wilting and yellow discolouration of your plants’ leaves. Sometimes, these signs can point to other problems with your plant, such as nutrient burn—when you’ve overfed nutrients to your plant. But if you do notice these potential indicators of root rot, it’s important to take a closer look at your plant’s roots.
To inspect your plant’s roots, gently pull your plant from its soil and feel the roots. If your roots are rotting, they will feel extremely wet and mushy, and have a black colour to them. Healthy roots can be black too, or pale in colour, but the main difference is in their texture. If the roots feel firm and robust, that’s an indication of health. If the roots are severely rotten, they may be so fragile as to fall away from the plant just by touching them. Rotten roots will also sometimes emit a bad odour.back to menu ↑
How to cure root rot:
Step 1: Once you identify root rot, gently run the plant’s roots under lukewarm water until most of the soil has been washed away.
Step 2: Then, use rubbing alcohol to sterilize a pair of scissors or small garden shears. Use this pair of clean scissors to gently trim away the mushy, rotted roots so that only the healthy, firm roots remain. This may require you to chop off a significant amount of your plant’s total roots system.
Step 3: Next, trim off one-third to one-half of the leaves that are on your plant. The reason you do this is because the more leaves your plant has, the more work it will take for your plant’s roots to support them. By trimming away some of the leaves, your plant will have an easier time regrowing its roots.
Step 4: Throw away the soil in the pot where the root rot took place. Wash the pot out with a bleach solution, then rinse it until it’s completely clean.
Step 5: If you have a fungicide solution on hand, dip your plant’s healthy roots into this fungicide to clear away any potentially remaining fungus.
Step 6: Put new soil into your pot, and re-plant your plant inside it. Do not fertilize the plant while its new roots are growing in to avoid stressing the plant.
Step 7: Be sure not to overwater your plant anymore. This means only watering your plant when the top of the soil is dry.back to menu ↑
What supplies you’ll need:
How to prevent root rot:
One of the main things you can do to prevent root rot is to make sure you’re growing your cannabis in a pot that allows your soil to properly drain. If your soil is draining properly, meaning excess water can move through the soil and exit out the other end, you will be less likely to experience root rot, which is often the result of too much water building up. Before watering your plants, feel the soil to make sure the top isn’t still wet. If the top of your soil is wet, you don’t need to add any more water.
It’s also a good idea to use pest control measures to avoid your soil from being invaded by pests like the fungus gnat, which is known to expose your roots to fungus and make them rot. Again, one of the best pest control methods for fungus gnats is making sure not to overwater your plant. Other preventative measures you can take include keeping your plant away from open windows, or areas where insects can get to it. You can also try laying a thin cloth over the top of your soil to prevent pests from laying eggs in your soil.
You can also release small predatory insects into your soil, so that they eat any pests that might damage your plant. This might make more sense for an outdoor grower, who’s plant is much more susceptible to pests.
Add Trichoderma (fungi) to your soil to protect your roots:
Trichoderma is a beneficial type of fungi that acts as a defence system against other harmful types of fungi, and other pathogens that could rot and kill your plant’s roots. You can often find this natural root-protecting fungi mixed into root rot treatment solutions that you can find online, or at your local gardening store. Trichoderma is great for growers who would prefer to be proactive and address any potential issues before they happen. Use Trichoderma if you’re inexperienced with how much water to give plants, or if don’t want the potential headache of having to treat your plant’s rotted roots.
Want to watch a quick and easy video tutorial to learn how to cure root rot? Check out this great tutorial by YouTuber GreenPlanet Wholesale!
Want to learn more about the best grow medium for your plant? Read our comprehensive guide to the best growing mediums!