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.
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.
While your plant is putting in quite some overtime to gain size and height, she will grow a number of new leaves mostly at the top of the main colas. Your cannabis plant is busy growing “green stuff,” like leaves and stems so she can become stronger and sturdier.
When the light cycle provides your cannabis plants with longer hours of uninterrupted darkness, they enter the flowering stage. Your plants will stop growing and instead put their energy into producing buds (flowers). Outdoors, this will normally happen when the days get shorter around the end of summer. When you grow indoors, flowering will begin once you switch your lights to 10-12 hours of darkness.
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.
Some of your cannabis plants’ previously white pistil hairs may now be turning darker into a brownish or amber colour. At the same time, when you check the trichomes of your plant, you may spot some of them becoming opaque. The trichomes becoming milky white and the hairs turning darker are all signs of your plants not being too far from harvest.
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.
Although your plant has officially entered the flowering phase, she will now have an increased need for growing nutrients. You should not abruptly change your nutrient schedule and use flowering nutrients from one day to the next. It is usually recommended that you continue to give growing nutrients for at least one more week once flowering starts.
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.
Once you stop feeding, your cannabis plants will take up whatever nutrients remain in the growing medium. Then, they will start to suck their leaves dry to get the nutrients out from these as well. This is why your cannabis plant will turn yellow in late flowering. Not needing to feed your plant in the last couple weeks provides an extra perk—it saves you money on nutrient expenses.
During this two-week period, you can periodically flush your medium with pure, pH-balanced water to get rid of any mineral deposits lingering in the soil. Make sure to drench the soil to full capacity so it picks up the nutrients, then drench it again and let it all drain out the bottom for a couple minutes. However, be sure not to water too frequently, as you don’t want to hurt your plant in its home stretch to harvest.
If all of these things still don’t help to keep the noise down, you can also fit a sound muffler to your fan. They look similar to a carbon filter, with a metal tube that you attach to your fan. You can then just fit a normal duct pipe to the muffler and should finally be able to enjoy greatly reduced noise.
After flowering for around five weeks, there are now solid cannabinoid-dripping buds found on your plants, which are still growing and expanding—but the biggest part of their development is already behind them. Your flowering plants should still be lovely and green as your ladies are firing up their THC production on all cylinders. The leaves around the buds are also becoming stickier, and the many THC-rich trichomes produced on them will later be used for making a nice lump of hash.
Ensure you are aware of the laws of your country.
Your selection of cannabis seeds could be guided by their required flowering time, as well as other factors such as their taste or effect. If you prefer a more “up” high rather than a heavy body stone, you will likely want a sativa-dominant cross that takes a little longer to bloom, typically between 8–12 weeks. Even so, do not forget that every plant is unique. There can always be early-blooming, medium-long-blooming, and late-blooming individuals in your cannabis garden, even from the same strain and the same seeds.
As harvest is just around the corner, it’s good to keep any fan leaves you trim from your plants as they too contain THC and can be later used to make hash or kief. More about this in our harvest section.
Flowering cannabis plants have additional demands for phosphorus and potassium, so it’s worth giving them PK 13/14 as extra stimulation for flower development. These substances are found in every basic nutrient mix, but in lower volumes. With some additional PK 13/14, you can get denser and more compact buds. If you are new to growing, it can be best to start with basic cannabis nutrients with NPK (nitrogen, phosphorus and potassium), plus a PK 13/14 additive for flowering and a root stimulator.
With a simple dimmer, you can set up your exhaust to suck away less moist air during the first few weeks of vegetative growth so your young plants develop more quickly. As soon as the plants become bigger, you can let the exhaust do a bit more work as they start to produce more moisture. In fact, once your plants are in full bloom around the fourth week of flowering, you should make sure your plants receive no more than the 50–55% RH threshold.
Learn all you need to know about the final weeks of the cannabis flowering stage, including ideal climatic conditions, how to know when to harvest, and more.