The great thing about growing cannabis in your outdoor garden is that, even though summer has finished, the next couple of months are a time to look forward to. In these two months your precious outdoor crop will ripen and be ready for harvesting.
This can be an anxious time for the marijuana gardener. You have been nurturing those little babies of yours since the Spring; protecting them from low temperatures, cannabis feasting pests and diseases and, in many cases, trying to keep those plants well hidden from the neighbors!
However, there is one seasonal enemy that causes every cannabis gardener to stand back, shake their fists and howl at the sky, “Nooooooooo!” MOLD!
1) Be Vigilant for Mold on Cannabis:
In northern regions of Europe, America and Canada, as the heat of the summer sun subsides and the daylight hours decrease, the garden begins to decay. There may still be some warm days but colder nights and Autumn rains bring the threat of mold and this can devastate your crop if you are not careful.
Hopefully you are growing a variety that is conducive to the climate for your region (for example Sweet Purple and Belladonna have been bred with mold resistance qualities). Particularly susceptible to mold are big bud indicas because it the moisture in those juicy buds can help it to thrive.
The key is to be vigilant, with daily checks of your plants for signs of early Botrytis. Look out for stems or the odd leaf changing to a shade of brown, which can be an early sign, as can wilting and spots o leaves. As it works from the inside out, by the time you notice patches of fluffy gray on your buds bud rot is fairly advanced.
2) How do I avoid Bud Rot?
Unfortunately, mold (also known as ‘bud rot’) is an efficient operator, with spores easily carried on wind or by touch. At this time of year they thrive and so your plants are vulnerable.
Good air circulation is a key defense against mold. If it is in a pot, make sure it gets a nice breeze to those budding branches. You could also investigate the ‘lollipopping’ pruning technique to remove growth from the bottom to allow more light and air flow to reach the lower buds. Some gardeners use a Neem oil spray, diluted milk spray or add a little milk to a feed to give their plants some protection.
If your plant is in a pot, it is always advisable to bring it under cover when there is heavy rain, and if not, a makeshift cover will help when there is heavy rain. Also avoid touching the buds with your fingers as this can create lesions in the outer plant tissue through which mold spores can enter.
It won’t help for this year, but training your plant or using a mesh or net to ‘scrog’ your plant will provide you with a more even canopy with more medium sized buds spread out and exposed to the sun, rather than the top-heavy traditional plant growth.
3) Mold on My Cannabis Plants: What do I do?
Don’t panic! This is going to be painful but you are just going to have to accept that you have a problem and deal with it (learning for next time!). Remove and destroy any affected area immediately and sterilize your hands before returning to your plants.
For these purposes, a bottle of surgical spirit (rubbing alcohol) is useful for sterilizing scissors. Some growers also recommend treating the stem stump (once the affected bud has been removed) with surgical spirit applied via a cotton bud.
Our best advice is: If in doubt throw it out. You do not want to be consuming moldy buds. It may make you want to cry but it is better to destroy than put your health at risk. However, armed with this advice and daily vigilance, you will be able to decrease your risk and ride out your crop to a rewarding harvest.