You’ve worked hard all summer in the garden, making sure your plants are happy. Summer turns to Fall, and just as the flowers begin to ripen bud rot sets in. Within a few days, you are scrambling to save your harvest. Outdoor commercial growers have the same problem with bud rot in the Fall, so don’t feel alone in this struggle. While there are no magic bullets, we are working with Mother Nature here, after all, the backyard gardener can easily prevent bud rot from ruining their crop by keeping in mind a few simple, effective, and inexpensive strategies. Read on to learn how to ensure clean, bud-rot free flower every year.
Location, Location, Location
Cannabis grows best in a sunny location with well-draining soil. Sound familiar? It should! Cannabis (which includes plants called hemp and marijuana) grows like many other common vegetables in your garden. Think tomatoes and peppers. One of the best things you can do to grow big and healthy plants, which also prevents bud-rot in the Fall, is to plant them in a sunny location.
Having both morning and afternoon sun will help keep the moisture off your plants’ flower. This lingering moisture is what leads to bud rot. If needed, choose a location that receives AM sun so any moisture that has settled during the cool Fall nights will be burned off first thing in the morning. If there is often an early frost or heavy rains in your area, also think about positioning your plants in the garden so that you can easily cover them if necessary. We will talk more about how to handle rain and frost next.
Strategies for Dealing with Bad Weather
You can’t control everything in your garden, but you can check the weather and get ahead of any problems before they start. First, let's talk about rain. Even at full maturity, your plants can handle some rain as long as it is followed by a few warm sunny days. This allows the thick branches of flowers, called colas, to dry out. This helps prevent bud rot which starts deep inside those colas.
If you are expecting multiple days of rain, or rain followed by many cool, wet days, you have a few options. Consider applying beneficials that help prevent bud rot like Bacillus amyloliquefaciens or Reynoutria sachalinensis. As a bud-rot preventative beneficials are relatively safe, easy to apply, and can be used before harvest. Follow the directions, and if you know you’re likely to have a rainy Fall, start applying beneficials before it starts raining so the beneficials can work well. Covering your plants is also an option. Mature Cannabis plants can tolerate a few nights of light frost, but ultimately frost is a killer. One option is to cover your plants to help protect them.
Keep in mind that the trick of spraying plants with water to prevent frost damage is not a good idea for Cannabis because of the thick colas (bud rot!). Ultimately, if you are concerned about impending weather and how it will affect your harvest, you can always harvest. Farmers face this dilemma every year as well and it is challenging to know when to proceed. If you are in the last week of flower before harvest your overall percent of cannabinoids might be a bit lower than if you wait. However, the flower structure and yield are already set, so you will still get an enjoyable crop without the worry of bud-rot taking it away from you.
Plant Selection Is Also Important
Tomatoes bred for a hot-house do not like being grown outdoors, and Cannabis is the same. Most Cannabis has been bred just to produce high levels of cannabinoids, not for good growing characteristics. Also, most of this breeding has taken place indoors. If you’ve ever grown out seed that you found in flower, and it produced a small, floppy plant, you have experienced this lack of breeding. If you are growing outdoors, which is still much easier with a not great plant than growing indoors, try to find seeds or clones that are known to do well outdoors.
When possible, if you live in an area with a short Fall (e.g. it starts snowing or raining early in October) grow varieties of Cannabis that are known to mature earlier, like the end of September. It is often difficult to know when a plant will mature, so your best bets are to pay attention to the location of the plants in your garden, and the weather as you move into Fall so that you can time any preventative measures like covering your plants, applying beneficials, or harvesting a bit early.