Unlike most animals, cannabis plants don’t create their own body heat. They’re reliant on external sources of heat to stay warm. That doesn’t mean they don’t have any natural mechanisms for controlling temperature, though.
As far as hybrid strains go, Silver Haze, Northern Critical, Blue Cheese, White Widow, and Somango are all popular with growers who live in colder climates. Outdoor growers certainly shouldn’t constrain themselves to growing only these strains, but they at least offer a good place to start.
The Effects of Temperature on Growth
Most growers realize that plants left in an uninsulated and unheated room will almost certainly die if they are exposed to below-freezing temperatures at night, but they don’t always know that plants also suffer from excessively high heat, especially in combination with high humidity. More about that later. For now, growers just need to know that while marijuana plants can survive within a pretty large temperature range, they require a much narrower temperature range to thrive. Here’s why:
Many growers intentionally stress their plants by exposing them periodically to lower-than-normal nighttime temps to increase THC content and improve flavor profiles. That’s fine, but make sure to not to overdo it and give the plant everything it needs to maintain an optimal growth schedule after acute stress.
Growers who’ve opted to build full-sized greenhouses can go one step further by installing one or more gas patio heaters. These heaters are cheap, efficient, run on easily available fuel, and can keep plants warm and happy even on frigid nights. Plus, they produce carbon dioxide as a byproduct. This gas can be converted during photosynthesis into the glucose plants need to grow and thrive, so growers who install gas patio heaters can also expect slight increases in their yields.
Two or three weeks after germination, your young seedlings should be ready for their new home. At this point you have two options; transplanting them into soil pots, or taking on the challenge of hydroponics. You’ll know when the seedlings are ready to be moved because the root system should start to poke out of the bottom of the wool blocks. As long as the roots haven’t begun to engulf the bottom half of the wool block, they will seek out water and nutrients in their new surroundings and continue to grow downwards.
Three fundamental principles will trigger that first small taproot to appear: warmth, moisture, and darkness. With the promise of moisture, a single root will take shape before slowly developing into the cannabis plant we know and love. In the right conditions, seeds will begin to develop within 12–36 hours of moisture being introduced to them.
Place one sheet of damp kitchen towel on a flat surface. Space your seeds a few centimetres apart before placing the second piece of kitchen towel over the top. You need to ensure both pieces are damp, not wet. Once again, when the white root tips reach 2–3mm, move the seeds (carefully) to soil pots. Use the same guidance found above for planting techniques.
PLANTING DIRECTLY INTO SOIL
Arguably one of the least effective methods, but it is still viable. Incredibly simple to facilitate, beginner growers may opt to germinate their seeds in a glass of water. Half-fill a glass or bowl with water that is approximately 22°C (71°F).
Probably one of the most common methods of germination. The kitchen towel method comes in several iterations. Some growers use cotton wool pads or absorbent pieces of paper. For this guide, we will be using kitchen towel as it is readily available and holds moisture relatively well.
The Royal Queen Seeds Feminized Starter Kit contains:
Start by filling pots with a premium-quality soil that has been soaked in water. Many growers also choose to lace the water with a root stimulator. Make a hole roughly 10–15mm deep. This will be your seed’s new home. Remove the seeds from their packet and place them into the pre-dug holes. Loosely cover the seeds, but be careful not to compress the soil above the seed too much. The root will struggle to penetrate solid soil, slowing plant growth. Lightly spray the top of where you placed the seed so that your growing medium stays moist.