How to Keep Cannabis Hydrated When It Is HOT

In the Heat of Summer…Hydration is Your Best Defense

When summer gets blazing hot, keeping your cannabis plants properly hydrated is a balancing act. It is easy to think that if it is hot, you should just dump water on them constantly. But over-watering in hot weather can actually drown your roots and lead to root rot because warm soil holds less oxygen. The key is watering deeply and strategically….if they are in the ground.

In pots it is more trying to water them enough. One must remember the bigger the plant, and the smaller the pot, and the hotter it is the more often you will need to water. The plants in the image above are a good example. You can see the plants are about 10 feet tall, and all are in 5 gal buckets…and, that summer it was over triple digits for 30 days straight! In the height of the heat I would have to water these plants 3 times every day.

One ‘trick’ to knowing when to water is not to wait till the plant actually wilts…as then you have waited too long….look at the plants leaves…they will lose their ‘gleam’ or brightness when they plant is entering a water stressed situation. That is when to water…do not wait for the leaves to actually wilt.

Instead of giving your plants a light sprinkle every single day, you want to water them deeply and less frequently. This coaxes the roots to grow deep into the ground where the soil stays cooler and retains moisture much longer. If you are growing in ground beds or large smart pots, slow-drip irrigation is your best friend. It delivers water straight to the root zone without creating runoff or evaporating into the hot air before it can soak in.

I water these plants about once a week (as often as I am up at the property right now) and I soak the entire hugelkultur bed they are planted in…I flood them.

If your plants are in fabric pots, they are going to dry out much faster than plants in the ground. The breathable fabric is great for the roots, but the hot wind will sap the moisture right out of the sides of the pots. During a heatwave, you might need to water container plants twice a day or more…depending on plant size, and pot size.

If you notice your plants drooping just a bit in the middle of a very hot afternoon, don’t panic and immediately drench them. Check the soil first. If the soil is still damp a couple of inches down, the drooping is just the plant’s natural defense mechanism to reduce moisture loss through transpiration. They will perk back up once the sun goes down. Only water if the soil actually feels dry to the touch.