There will be a ton of foliage at this point and the plants will want more water than seems possible. Any training should be done at this stage, as long as the plant is healthy and growing rapidly.
The weeks involved for each plant are variable for a lot of conditions, but this is a good general gist of what each week and group of weeks involve for standard cannabis grow.
A healthy plant will start turning a more vibrant green color and those blades will finally start becoming sizable, it will start looking more and more like a marijuana plant at this point. Once these seedlings fully develop these initial leaves and blades, they will be considered maturing and move onto the next stage of growth.
7-12 week-old plant
Featured Image Credit: High Times
As the taproot of the germinated plant begins to take hold, the first set of iconic fan leaves begin to develop. This signals the beginning of the plant’s seedling stage of growth and should be placed in a large growing area immediately if it hasn’t been done so already.
The growth of the plant will begin to slow down here as well, eventually stopping altogether as the plant’s energy will be focused entirely on the buds.
It can last anywhere from 3-16 weeks, so knowledge of the particular strain being used is crucial here.
Although this plant recovers, you can see how badly the burns stunted its growth, and you’ll notice that the regrowth that follows is a bit odd as the plant “ditches” the burnt parts and then gets back into the swing of things.
You can see the extreme stress the Pyrethrum combined with grow lights has put on the young plant.
Recovery of Topped Marijuana Plant & Formation of 2 New Colas
This one is a little bit hard to watch as this Purple Haze seedling is hit by a strong insecticide (Doktor Doom) around 0:31 to combat spider mites.
The above time-lapse video spans 40 days of growth. A frame was taken every 6 minutes. 50fps .
All plants do that. It partly has to do with their Circadian rhythms. Plants must put energy into keeping cell walls rigid to hold up the leaves. Kinda like using their “muscles”. With plants like cannabis, the leaves tend to “rest” at night and “perk up” when they “think” the sun is going to come out.
This phase of flowering where your plant is starting to spend increasingly more energy on growing flowers is particularly critical. Make sure that the nutrients you give are appropriate and check the labels for the recommended dosages.
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.
Check Your Plants For The Right Harvest Time
Not all cannabis strains require the same amount of time for their flowering, but many varieties will be ready to harvest in these last three weeks. There are, however, not too many strains that will be ready before week 8.
Cannabis plants like red and orange wavelengths during flowering (between 580–700nm) to encourage the ripening of their flowers. For best results, use a grow light with this spectrum during the bloom phase.
Transplanting shocks your cannabis plants. Always avoid transplanting right before or during the flowering phase to avoid damaging your yield potential.