The point made in this article about irrigation is that water should be delivered to the soil in the correct quantity. Many people invest the right amount of money in soil-substrate growing but do not irrigate correctly, which will ultimately cut by half their yield. There are people who water plants every day until water flows out; other people irrigate when leaves start to hang on plants, and there are even those who have simply learned on the Internet that, when a plant reaches a certain size, they should deliver 200 ml of water, which is wrong as watering depends on the initial climatic situation and the type of pot.
How is it possible to irrigate in such a way as to leave the soil wet and airy? This is very simple: every day or every other day you should lift up the pots and those that are still heavy should not be watered. All others, instead, should be abundantly watered in such a way as to let water flow out and leave the soil wet. If plants remain without air for a few hours on the floor, it will not be a bad thing. Water in excess will flow away and this will cause the soil to become airy again. By contrast, if you water plants directly again, the soil will be permanently wet, which will make the plant suffer. If you only water again when pots are lighter, instead, the plant will for the most part have enough air for root breathing. It is practically irrelevant if plants remain drowned for 12 hours. However, if after a few days the pot becomes lighter, it should be properly watered. If the soil is bone dry, the plant will stop growing and even wither in two days’ time. Excessively dry soil cannot withhold water and must be watered again after at least 20 minutes in order to absorb water. In addition, water should be delivered at lukewarm and not cold temperature, not to cause a shock in the roots.
Many people do not have the habit of lifting up pots and tend to water abundantly if they see dry earth on top of each pot. Depending on the soil, however, the upper layer could dry up, whereas the core could still be damp. If water continues to be delivered, it will be too much and the plant will be damaged. There are soil types, instead, in which, despite abundant watering, if the above layer is dry, this means that the whole soil block is dry. For different types of substrate mixtures, therefore, the dryness of the upper soil layer is a giveaway for lifting the pot. It the pot is still heavy, there is no need to water. If, on the other hand, the pot is lighter, then you should water plants as usual.
If you water abundantly in a grow tent with thick soil and the water forms a puddle, there may be pots that are so flat that the water puddle will be on the same height as the soil. Water will be absorbed into the soil, which could lead again to a build-up of damp in the event of a highly absorbing type of soil. Normally this is remedied by using dry soil or by raising pots to a higher level, e.g. by using stone tiles or stones; wood or polystyrene would instead get mouldy. Plastic spacers could also be used.
Even when you do everything right, if watering is wrong, your yield will be less than half of what you expect. Conversely, if many errors are made, even with the right watering technique no perfect results can be obtained. However, those who seek perfect results and grow on a soil substrate should absolutely refine their watering technique. Many inexperienced growers only need to irrigate correctly to harvest much larger quantities of good weed!