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.
As your plants become more picky, you should check for potential deficiencies that could manifest in various ways, such as discoloured, yellowing leaves or loss of leaves entirely. At the same time, you should also check your plants for signs of possible overfeeding (“nutrient burn”) that could show up around this time as well. Nutrient burn will usually show in the tips of the leaves becoming discoloured. If this happens, you need to cut down on feeding.
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.
In week 5 of flowering, you can observe the buds all over your plant becoming thicker. You may also spot new buds growing in new places such as along the main cola. With buds abounding, your cannabis plants will get fatter every day. This is a surefire sign you are in full flowering mode. At this point, your plant will have a very intensive odour. Ensure that you have a good ventilation system in place if you grow indoors or in a region that doesn’t allow for legal cultivation.
At the locations on the plant where you previously saw some hairs, you can now see the first signs of real buds developing. There still won’t be many resin glands and trichomes on your plants, which means that the smell won’t be too pungent yet either.
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.
With the stretching of cannabis in early flowering, you may possibly want to think about training techniques such as low stress training (LST). This is where you bend the stems down and away from the centre of the plant so you can get an even canopy for a more efficient use of your grow lights. This can help you obtain much better yields later on.
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.
What happens during flowering and at what exact time can somewhat vary depending on the particular strain you are growing. So don’t expect your plants to follow this schedule to the T; see it more as a general guideline that you can go by. Let us look at the flowering phase of cannabis week by week.
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.
The flowering period of indica plants is always shorter than that of sativas. This means that an Indica needs a higher concentration of nutrients to provide the maximum flower production. With sativas the opposite is true, with more weeks of flowering, the lower the amount of nutrients required weekly although if we check the total at the end of the crop both plants will have used almost the same amount of liquid fertiliser.
We can also find certain fertilisers like Powder Feeding that are formulated specifically for long or short flowering varieties:
When liquid fertilisers are used, their nutritional composition in terms of NPK and the ratio of these 3 macro nutrients should be taken into account. With commercial bottled nutrients, the same flowering fertiliser is used for both indica and sativa, but with a dose that varies according to the week. So we won’t give the same amount of nutrients to the indica plants as to the sativa plants over the same time period, but we’ll vary them as needed.
As we can see, in the first weeks of flowering during the stretching period, (table for indica of 8 weeks) the requirement for nitrogen is very high. During this stage the plant requires high doses of nitrogen to be able to stretch, grow and start to form the plant structure where the bud will appear.
33 days, the structure is created, now the buds begin to fatten
The graphic shows the different nutrients that the plant requires and the difference between one type of nutrient or another (nitrogen, phosphorus, potassium or calcium) depending on the stage of the plant.
45 days, buds are fattening with the resin building up
In the case of sativas, it’s important to remember that these plants can as much as quadruple their initial size, meaning a 30cm plant can finish at 1.20m in height. For this reason, when it comes to very long flowering sativas with a significant stretch as mentioned, the plants can be started at 12/12 from germination, avoiding excessive vegetative growth. They can also be pruned and trained if you want to grow in SCROG with fewer plants per m2.
Phases of plant life
Without a doubt, flowering is one of the crucial stages in cannabis cultivation. In this article we tell you everything you need to know about the blo