If you want your plants to be marvelous bushes that bring a gigantic yield, you should master a simple trick called root pruning.
The idea is to let an indoor plant's root system develop normally, as if it were growing outdoors, in rich soil. Unless you are using aeroponics, regular plants in the old-fashioned pots often suffer from the lack of air. We bet you know the situation when you take out the plant for placing it into a bigger pot and see a tight knot of roots in the shape of a pot.
If you place this kind of plant into a new, bigger pot, the new roots will not be able to untangle out of this bundle. They will keep on growing along the knot unable to absorb water and nutrients.
At the same time, if you decide to break the knot before transplanting your cannabis, tender plants can suffer from stress, and it can make them grow slower, or in the worst scenario, lead them to death.
Sometimes, it is even difficult to get this kind of plant out of the old pot as the roots not only wrap the inside of the pot but literally grow into it. Such roots are usually so tangled it is impossible to get the plant out of the old soil without stressing it.
The reason why it happens is the lack of air. If your soil is fat, it will compress with every watering, and you will get less and less oxygen in the soil. This is why the roots will instinctively lean to the place where there is access to air—the bottom of the pot and its walls.
Depending on the strain, your plant can either grow around the container in a constricted pattern creating a knot around the inner side of the pot or make a “double bottom” concentrating all the roots in the bottom part and even letting some go through the hole outside. The roots may twist, go spiral, kink or get squished instead of developing in a natural bush-like structure.
To avoid this, you need to prevent lack of oxygen in the soil. First of all, do not take a pot that is too small—the more soil your plant can use, the more space it has for developing the root system, and, as a result, the more nutrients it can absorb.
Second, add vermiculite or sand to the soil to make it lighter and to let the oxygen get inside easier. In a flower store, you can ask for any other products that can prevent the compressing of the soil.
And last but not least, use air-pruning.
Air-pruning offers a different way of treating the roots. All you need is simply to make additional holes in the walls of your pot. This way, air will “prune” the roots of your plant so that they do not go to the side or bottom of the container but develop normally in the middle of the pot.
Simple access to air through the side of the container makes miracles for the root system:
The easiest and probably the cheapest way to make a proper container for your plant would be to use any growbag. The ones that are made of fabric are better as they have the right structure for air access to the container. A plastic growbag will work too if you make lots of small holes in its sides all around the bag. There is no reason for creating big holes as you do not want the soil spilling out. Plus, too much oxygen or light is not good for the roots either. You need to strike a balance.
Some growers also use laundry baskets with simple fabric inside. This kind of container can also work, but it requires a bit of accurateness from your side as usually the holes in such a basket are quite large.
So, growbags work fine; however, you can use them only once.
If you are planning on using something that can serve you many times year after year, choose solid pots.
Today, there is a quite wide choice of aero-pots in flower stores. You can also make a DIY container by simply drilling holes in a plastic pot.
If you decide to use air-pruning indoors, you should provide enough airflow to the plant and control the humidity. Do not water the plants from the bottom; it is better to do it manually from above. Do not forget to check the bottom of the container from time to time in order to make sure you are not giving too much water (if you are, the bottom will be soaked).
If you are growing cannabis in a greenhouse, a mist irrigation system can serve you best. It is not so expensive to make it, but it gives great results.
Using aeropots can also be useful as you can plant a seedling directly into a big container and not bother later with re-potting it. Because of the soil's constant access to air, there will be no need in stressing the plant as your cannabis will develop a dense root ball of small tender roots right from the beginning. This kind of root system significantly increases the survival rate of the plant, so even the lack of nutrients or a high temperature will not cause any irreparable harm.
If you do everything right, no roots should appear outside the container. This refers to both side and bottom holes. If you spot some roots anyway, try to add a fan that would blow on the container (not the plant) or try to decrease the humidity. However, do not cut those stray roots, leave them as they are.
The experience of many growers shows that using air-pruning gives amazing results: the plants grow healthier and bigger, the cultivation time is shorter, and the yield is more abundant. So if you have not tried it yet, there is no reason to postpone it—get your ladies air-pruned!