How long can a weed plant withstand overnight frosts? — Thanks in advance, Josh K.
Thank you for your question. A heavy frost is definitely a bad thing for a cannabis plant and can kill it quickly. On the other hand, a light frost is usually not a death sentence and many plant varieties will bounce back unharmed. As a cannabis grower in zone 5, my garden must endure frost most outdoor growing seasons. From my experience, there are several factors that will affect a cannabis plant’s ability to withstand overnight frosts. I would first like to note that although many varieties of cannabis can withstand overnight frosts, it is never ideal. Frost can unleash a whole host of problems, including rapid mold development or damaged trichomes.
Growers who live where frosts occur during the latter part of the outdoor season should pay close attention to weather predictions and/or patterns so the plants can either be covered/protected or harvested before anything devastating occurs. However, some growers are not able to cover/protect their plants and, if it is not yet the optimal harvest time, they must let the cannabis plants endure a frost (which is better than an early harvest). Every garden is unique and it is up to the grower to decide what is best for his or her plants: whether to harvest early or try covering/protecting.
“Marijuana plants that have their roots planted directly into the soil are also more tolerant of frosts as the root zone is more insulated compared with plants in a planting container.”
Generally speaking, indica-dominant varieties of cannabis are more tolerant of frost than sativa-dominant varieties. Marijuana plants that have their roots planted directly into the soil are also more tolerant of frosts as the root zone is more insulated compared with plants in a planting container. The size and density of the plant’s colas, or flowers, will also affect its ability to safely withstand overnight frosts. Typically, the larger and/or denser the buds, the more susceptible they become to molds and mildews developing after an overnight frost due to the moisture created the next day when the frost melts.
Another crucial factor in determining a cannabis plant’s ability to withstand frost is the weather patterns at that given time. More specifically, the temperature the day following the frost will be a big factor in the plant’s capability of withstanding the frosty night.
For example, if there are overnight frosts, but the next day has a high temperature of 60°F with plenty of sunshine, the plant is much more likely to safely withstand the frost than if the weather the following day is 40°F and overcast. I have experienced both of these situations and, in the case of the latter, molds can develop within a day or two and can quickly decimate an otherwise healthy cannabis crop. Conversely, I have also experienced warm, sunny weather after a frost and the garden continued to grow and flourish. I hope this answers your question.
Keep on growing,
Lee G. Lyzit
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