Some growers are attracted to the idea of 12-12 from seed, because it means that harvest will come sooner. How long does it take to grow a plant from seed to harvest?
With such small plants, you don’t have the time to train your plant, which gives you much greater control over the final shape and size of your plant, improving yields without adding much time.
While I wouldn’t recommend 12-12 from seed, and no longer ever use this technique myself, there are growers who are going to do it anyway.
Keeping plants in tiny containers may be important when growing in a very space-limited grow space, such as growing in a space bucket for stealth reasons.
But does the 12-12 from seed technique work to give you a faster harvest, and if so, what are the results?
I have changed cannabis plants over to the flowering stage from seed, but no matter what the light schedule, plants don’t start flowering (making buds) until they are about 3 weeks old. Initiating a 12-12 light schedule at 3 weeks old from seed is as early as I’d recommend for this technique, if you choose to use it.
But it’s possible.
But like this extreme girl to the right (less than a foot tall and grown under CFLs), I’ve experimented starting the plants on 12/12 from seed to keep plants REALLY small.
Giving a 12-12 shedule when a cannabis plant is younger than that will not work to make the cannabis start flowering – a cannabis plant will only grow vegetatively for the first few weeks of life, and giving them less light will only cause them to grow more slowly.
Learn what it means to give your plants "12-12 from seed" to force them to start making buds early.
Important things to know in this early stage of flowering.
To properly feed your plants once they start to flower and to initiate the first signs of growing buds, you should check your nutrient manufacturer’s schedule. It is normally around this time at week 2 where you will have to increase flowering nutrients to help your plants reach their maximum yield potential.
The flowering stage is when your cannabis plants grow their aromatic and soon-to-be-smokeable buds. This is a particularly important stage in your cannabis plants’ life cycle. A lot happens in the flowering stage; learn how to care for your plants through every week of flowering.
Your cannabis plants have still not entirely stopped growing and will now be about 50% bigger than what they were just three weeks earlier. Although still stretching a bit, the stretch will now gradually slow down and soon come to a complete halt.
At week 4 of the flowering stage, your cannabis plants will likely have stopped growing altogether and are now spending all their energy on growing buds. There will still be white hairs sticking out from the buds, but the buds themselves will become bigger and fatter with each day. With more and larger buds growing, your plants will now produce more trichomes, making the odour a lot more noticeable at this stage.
If your cannabis plant happens to be a male, it won’t grow these “hairs,” but will instead grow small pollen sacs. Should you grow regular, non-feminized plants where you don’t know their gender, now is the time when you should “sex” your plants so you can separate the males from the females. The males won’t grow buds and will also pollinate your females, causing them to grow seeds. This is something you do not want to happen.
When the flowering period starts, it isn’t an abrupt change in your plants’ growth. Cannabis won’t just stop growing and then go into flowering right away. In these first weeks of flowering, many cannabis strains may indeed undergo a considerable growth stretch. This is important to know when it comes to feeding your plants properly, but also if you want to give them sufficient space to grow.
Depending on the flowering time of your particular strain, the time for flushing your cannabis plant is normally two weeks before harvest. When you “flush,” you stop administering nutrients and give the plant only plain, pH-balanced water in these final weeks. This will get rid of (flush out) salts and minerals in the soil which will make for a better and more pure-tasting bud. Otherwise, your smoke will be quite harsh and can have an unpleasant, chemical taste.
For most cannabis strains, the flowering period will last about 7-9 weeks, although some sativas require even longer for their buds to mature.
What happens during the flowering phase of cannabis? Learn about flowering week by week. This guide will help you maximise flower production and THC content.