If you’re growing indoors, you can force a weed plant to flower after only a few weeks when it’s small, or after several weeks when it’s big. If you’re growing outdoors, you’re at the whim of the seasons and will have to wait until the sun starts to go down in fall for it to flower and then to harvest.
The flowering stage is the final stage of growth for a cannabis plant. This is when plants start to develop resinous buds and your hard work will be realized. Most strains flower in 8-9 weeks, but some can take even longer, especially some sativas.
How long does it take to grow a marijuana plant?
Two rounded cotyledon leaves will grow out from the stem as the plant unfolds from the protective casing of the seed. These initial leaves are responsible for taking in sunlight needed for the plant to become healthy and stable.
We can’t stress enough that the timeframes in the above graphic are ranges of time for the Northern Hemisphere. You’ll need to adjust them based on your specific region and local weather and climate.
Be very careful to not overwater the plant in its seedling stage—its roots are so small, it doesn’t need much water to thrive.
Humidity levels below 20% will seriously stunt the growth of your seedlings and may cause them to develop symptoms similar to some nutrient deficiencies (yellow or spotted leaves). Humidity levels above 60%, on the other hand, will cause your plants to develop wet spots that can cause foliage to wilt or rot, as well as attract fungi and/or other pathogens and pests. Once your seedlings enter the vegetative phase, you should keep relative humidity at 50%.
Overwatering seedlings is one of the most common (and most fatal) mistakes rookie growers make. Unfortunately, it’s an easy crime to commit; scared to let their seedlings’ soil dry out, inexperienced growers often end up watering their plants too regularly. This essentially drowns a seedling’s tiny root system, starving the plant of oxygen and causing it to droop.
STEP 3: MASTERING THE SEEDLING STAGE
When growing autoflowers, we recommend planting them directly in their final pots. Because of their short life cycle, it’s best to avoid putting autoflowering strains through any kind of unnecessary stress, including transplanting. While the exact pot size you use will vary depending on the strain you’re growing and the size of your grow space, most auto growers use pots between 5–15l.
Cannabis seeds already contain two cotyledons (or embryonic leaves) that unravel and push the seed casing from the shoot. After the cotyledons emerge, cannabis plants will develop their first set of true leaves. These will grow out of the main stem and have just one finger.
Besides light deprivation, there are a handful of other factors that could be causing your cannabis seedlings to stretch. One common cause of leggy seedlings is poor nutrient content in the soil.
Just like baby humans, cannabis seedlings are super fragile and need plenty of tender loving care to flourish. Unfortunately, many growers run into the same issue during the early stages of their cannabis plants’ lives; their seedlings grow long, stretchy, and weak stems. This, in turn, can lead to a host of issues that put your crop at risk of delivering subpar results.
Finally, cannabis seedlings can also stretch if they’re receiving too much or not enough light per day.
What Causes Abnormal Stretching?
In optimal conditions, the seed shell, or husk, will crack open and a taproot will pop out, immediately digging further down in search of a water lifeline. Soon, you will see a sprout rise from the under the soil, spread out its first baby leaves (cotyledons), and then you will start noticing the first set of true leaves. Leaves have an equally important job as the taproot, but they are in search of another food source – light. Quite literally, a plant uses light to digest what it brings up from the soil.
Abnormal stretching in the seedling phase is a sign of stress. By far, the most common situation that causes seedlings to stretch and topple over is light deprivation.
Stretchy cannabis seedlings can be a pain to handle and transplant. Their stems can be very fragile, and once they start vegging, their foliage can be off-centre due to the weird stretch they underwent as seedlings.
Below, you’ll learn how to prevent and fix stretching in cannabis seedlings.