High summer temperatures can make your cannabis plants wilt, look droopy, cause leaf curl, and even curtail trichome production.
Excessive heat can also slow nutrient uptake, and if grown in pots can cause the root mass to over heat.
Most cannabis strains can easily withstand temperatures of close to 100 degrees Fahrenheit. But, when outdoor temperatures exceed 100 degrees, your plants can begin to suffer.
The western USA is struggling through a heat wave right now, and, where I live in WA state the highs have hovered around 115 degrees for the last few days.
So….what to do?
There are several tools cannabis cultivators can use to help them beat the heat!
- Utilize shade clothe. Shade clothe can lower temperatures when suspended over your cannabis crop. They do somewhat limit the amount of sunlight, but not enough to slow the plants growth much. I always use shade clothe on my greenhouse in the summer heat.
- Grow plants that have come from regions of the world that can experience high summer temperatures.
- If growing in pots….bury them in the ground so the root mass is cooler. One must realize that a pot sitting in the sun on a hot day can get as hot as the ambient temperature, and can bring plant growth to a standstill. Your cannabis plant will no longer be thriving…..it will just be surviving.
- One can actually water with ice instead of water. I have done this (in my greenhouse) and the plants seemed to love it…a cold drink of water on a hot day.
- Do not try to germinate seeds on those hot days, nor grow seedlings under the full summer sun. Well established plants can withstand those high temps much better then seedlings.
- Water….water….water….This is what will help your plants withstand high heat of those dog days of summer. Give them a cool drink on those hot days.
- Hopefully where you grow the nights are cooler. This can give your plants a nice break from the heat. And help them to withstand those high daytime temps.
- You should be aware cannabis plants can withstand high temperatures better when in their vegetative state. Once flowering begins the plant is looking for cooler fall weather. That being said, I have had auto-flowering cannabis plants flower beautifully in the heat of summer.
In conclusion: High summer temperatures do not need to be a deal breaker by any means! By taking a few precautions one can grow some great cannabis even in a hot spell.
I grew the big sativa that made up the bulk of my free seed offer seeds in my greenhouse through some very hot summer months. I was working long hours during that time and couldn’t care properly for her.
The temperatures exceeded 130 degrees in the greenhouse. I didn’t even put shade clothe on it. She was growing in the ground. All I did is pour the water on her. I would leave a hose just dribbling at her base, so she had cool water most days.
She thrived, grew to over 8 ft tall, and produced over 50,000 beautiful beans! Here she is pushing on the top of the greenhouse. She was a Beast!