If you buy a clone from a grower or breeder it will be a seedling, so you can skip the seed germination phase.
Cannabis plants are considered seedlings until they begin to develop leaves with the full number of blades on new fan leaves. A healthy seedling should be a vibrant green color.
The biggest variability in how long a marijuana plant takes to grow will happen in the vegetative stage—after the seedling phase and before flowering.
Generally speaking, it takes anywhere from 10-32 weeks, or about 3-8 months, to grow a weed plant from seed. It’ll be quicker if you start with a clone or an autoflower seed.
Marijuana light cycle: indoor—16 hours a day; outdoor—at least 6 hours of direct sunlight (“full sun”), plus several hours indirect sunlight
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.
What are a weed plant’s growth stages?
Flowering stage length: 8-11 weeks
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.
Fr om day 1 of your marijuana plant’s life to a smokable harvest, you’re looking at 2-6 months. Many factors affect the total time (especially the strain and size of the plant) but the average grow takes 3-4 months .
You want to get an auto-flowering strain. These cannabis plants automatically start making buds after about a month from germination, and are ready to harvest by the time they’re 2 or 3 months old.
How to grow marijuana as quickly as possible:
These vegetating plants are about 4 weeks old from germination
This marijuana plant spent about 6 weeks in the vegetative stage before being changed over to flowering and yielded just over 6 ounces at harvest. View the complete grow journal with instructions on how to grow your plant so it looks just like this at harvest!
Before You Start Growing Weed
Your plant will likely double in size (maybe a bit less, maybe more) from when you first put it into the flowering stage; this is known as the Flowering Stretch. So make sure you end the vegetative stage before your plant reaches half the final height you want, or your cannabis plants may outgrow your grow space during the flowering stage!
Medium (8-12 weeks)
Time Needed to Grow Weed, From Seedling to Harvest
So, after you’ve bought seeds and equipment, grown a plant from seed to harvest, trimmed, dried and cured your buds, that brings us back to the original answer…