Why is washing the roots so important before harvesting?

plant root

With outdoor plants in full bloom, these are times when poor choices can negatively affect the harvest. We may have large, resinous buds with an incredible aroma, but when smoking them we can be disappointed because their flavor is too strong or that it “scratches”. And the main cause is that of not having done a good root wash, or that it has not been done well.

Anyone who for any reason has had to harvest their plant or part of it without doing a root wash, will agree that its flavor leaves much to be desired. And sometimes, not even curing for months can soften its flavor. So if there’s no good reason not to, it should be a must whenever it’s grown in pots.

A root wash, as its name suggests, consists of cleaning the substrate to remove the nutrients it stores. With this we get the plant to stop feeding on the nutrients in the soil, and begin to use the nutrients stored by the plant matter, mainly the leaves. And since ultimately what we smoke from a bud is mostly vegetable matter, it will have a milder flavor.

When to do the washing?

As a general rule, it is usually done between 10 and 7 days before harvest. In any case, it is not advisable to do it too early, since if we cut the nutrient supply of a flowering plant prematurely, the buds will not reach their maximum power.

The experienced grower will be able to calculate this by looking at the appearance of the buds, since to be guided by the cut faces given by the banks is a bit ambiguous. In the same variety grown one in the north and the other in the south of Spain, there may be several days of difference in the harvest.

Ideally, you should always have a microscope to carefully observe the trichomes. In an immature bud they are transparent in color, while in a bud perfect for harvesting they are mostly milky in color. The time to do the washing is when you begin to see how they change from transparent to milky.

How do you do a good root washing?

The rule that is usually used is to use three times as much water as the pot’s capacity. In other words, for a 20-liter pot we would use 60 liters of water, for a 50-liter pot we would use 150 liters of water… But normally it is not necessary that much and twice as much is enough.

Obviously when you have enough plants in large pots, a large amount of water is needed and in most cases it will be impossible. So the normal thing is to resort to tap water, which as we know is chlorinated. Let’s also think that at that point in the crop where we cut off the supply of nutrients from the soil, it will matter little if we destroy a large part of bacteria and other beneficial organisms that are responsible for facilitating the assimilation of nutrients.

In any case and whenever possible, it is interesting to have one or two buckets of still water with the pH regulated to add it at the end. But to start with, with a low-flow watering can or hose, add a little water to each of the pots, allowing it to slowly absorb into the substrate.

Repeat again adding another little water to each pot. In this way we will achieve that the entire substrate is moistened and there are no areas of dry substrate. And do this until you see water start to come out of the drain. Then and with the substrate completely flooded, you can add water in quantity to each pot.

At first the water will be a dark color, but little by little it will clear up until it is completely transparent. To finish, add another good amount of the settled water with the regulated pH, and continue with the next pot. The usual thing, unless the same variety is grown, is that the root washes do not coincide on the same day.

If it seems that you are using too much water, you can also choose to use a salt cleaner or the typical  flush  that you can find in any grow. What they do is dissolve the salts from the substrate, and then remove them more easily and with less water. They are added to the irrigation water as if it were a compost, and when they have acted after a few minutes, it is watered with clean water so that the salts are dragged towards the drain.

What to do after a root wash?

Well, we will simply water when the plant needs water with the pH regulated until harvest. It is normal for the leaves to turn yellow or the plant to develop deficiencies of all kinds. But in the end it is the objective, that the plant, if possible, deplete the nutrients. What should not be done is to use any type of fertilizer after a wash since it will not have served to do so.

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