How Do I Control Bud Rot?

Prevent Bud Rot

These are the most important points to remember...

Good air movement - Create good air circulation and make sure there’s always plenty of air moving over all the buds and leaves.

Keep plant warm, if possible - Temperatures below 68°F (20°C) creates the right environment for fungus spores to germinate. Controlling temperature goes a long way.

Avoid letting buds stay wet - Don’t allow buds to sit in damp or overly humid conditions for long. Protect your plants from rain and control the humidity.

Remove all affected buds immediately - Carfully remove and discard all buds that have possibly been affected by bud rot. Don't let any rot touch other parts of your plant. This helps prevent bud rot from spreading.

Other tips to help prevent bud rot...

Avoid plant wounds. Avoid injuring your plants, especially in the flowering stage. Don’t leave open wounds to seep out water and nutrients - cover any open injuries with tape or some other “cast” until injury closes up. Also avoid pests and keep plants healthy. A healthy plant is much less susceptible to infections.

Defoliate leafy plants. Remove leaves on very leafy plants, but don't take too much. In fact you want to take off as few leaves as you can, especially if growing outdoors.

Only remove leaves that are covering or touching bud sites, as well as any leaves that are laying on top of each other. Your plant won't "mind" if you only remove leaves from leafy areas, and this prevents moisture from collecting into damp spots, while also improving air circulation around buds.

Watch out. Watch plants closely for signs of bud rot in the late flowering stage, especially on large or dense buds, and especially after cool, wet weather..

When growing outdoors...

Get a strain meant for your local weather. If you live in a place that has short summers and gets cold or rainy early in the fall, don't get a strain that was developed near the equator!

There are fast-flowering, cold-resistant cannabis strains which are designed for growing outdoors in cooler or more rainy climates. For example many auto-flowering strains have quick lives - perfect for a short summer before the Autumn rain or frost.

A good outdoor strain for those worrying about bud rot might be Auto Frisian Dew, an award-winning, mold-resistant strain made for outdoors. This strain goes from seed to harvest in about 12 weeks. Just plant seeds after the last frost in the Spring, then harvest 3 months later.

AutoFrisian Dew is resistant to fungus like bud rot. This strain is quick to harvest and will grow in any climate which has (at least) 3 warm summer months before it starts getting cold or raining.

Breezy location - Try to plan your grow spot so your plants get a breeze, but not too much wind. This can be tricky, and it may mean visiting the grow spot a few times before planting.

Protect your buds from rain. If you know there will be drizzly conditions, cover your plants with a tarp to protect them from most of the rain. Don't put tarp directly on plants or you'll hurt you buds. Install the tarp up above the plants, and make sure it's held up by the center part, that makes it so rain runs off the sides of the tarp instead of collecting in the middle.

Shake plants. Some growers shake their plants on dewey mornings or after rain, so any water drops that form on the leaves don't become breeding grounds for spores.

Fungicides, Neem Oil & Burning Sulfur

In the flowering stage, never use fungicides, spray affected buds with Neem oil, or burn sulfer.

These common tactics are not effective at stopping bud rot, and will make your buds taste, smell and look terrible.

Some growers use fungicides made specifically for Botrytis in the vegetative stage. But when it comes to cannabis, fungicides can only be used as a preventative before any buds have formed.

If you already have bud rot and can't fix your environment (which is the best way to kill Botrytis), I highly recommend cutting your losses and taking down the plant.

Most fungicides are not effective for bud rot. If you do plant to spray plants, it’s recommended to get one that’s specifically been developed to combat Botrytis.

Any treatments for Bud Rot should be applied in the vegetative stage as a preventative.

There's nothing you can spray on your plants after bud rot has already formed. Unfortunately, there aren't any effective fungicides or other treatments that are safe to use with cannabis in the flowering stage.