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How to flush cannabis plants

Flush your plants it's a commone xpresion in-between growers, specially in those moments  that, for any reason, it is necessary to free plants from nutrient locking. It is known as root flushing the process where growers proceed to water plants with abondant quantity of water (just water, with no nutrients added) to make decrease the quantity of fertilizer accumulated in substrate.

What is a root flushing?

It is known as flushing the process of reducing the quantity of nutrients accumulated in substrate. This process can be done because of an intensive use of fertilizers, because grower notices an excess of nutrients in plant's schedule, to prevent against nutrient lock in substrate, or toget rid of nutrients used along the cycle before harvest (Process in wich the goal is to get rid of nutrients in plants to favour a better taste of the crop).

How flush cannabis plants

How to do a proper flush?

There are many ways to do a proper flush to your plants:

- the most common one is to proceed to water your plants with 5x-10x the quantity of volume of your pots (i.e: 3 liter pot > 15-30 liters of water). Along this watering we will see how the draining water changes its color from a dark brow to transparent, indicative that most of the nutrients have gone away. This formula is specially good if our intentions are a sooner harvest, because after this flushing we just need to wait for 10 days more and then harvest. The best advantage of this technique is a shortened period of time before harvest, thanks to the acceleration of the process to free the substrate from nutrients.

- If we're not in a hurry, another great formula to do with a good flushing is to proceed with the necessary waterings without nutrients nor boosters (the amount of water needed for a normal irrigation) until we see that plants start to fade to yello (symptom that nutrients in substrate had been consumed, and plant starts to cover its needings consuming reserves in leaves. This method is the most natural one, and the preferred by non-comercial growers, because the process occurs in a more progressive way, without stress, in addition to a lower water consumption, what also means some money savings.

- The third method is using chelated agents that will attract heavy metals (the main function of chelating agents is to avoid toxicity of heavy metals to human being). These chelating agents form complex with heavy metals ions, what helps free the substrate form them, and then accelerates the process of flushing. There are many high quality products that can do this job, specially interesting for those growers on hurry to harvest, and for those growers using hydroponic systems. We've tried many of them and we can highlight the beneffits of using CannaFlush by Canna, Final Flush by Grotek or Flora Kleen by General Hydroponics.

* In any case it is important to highlight that if our goal is to clean the substrate from nutrients, we should never use tab water, because this water has minerals dissolved (in more or less quantity depending on your area). If we want to properly flush our plants the most important thing is to use RO water. This type of water assures no minerals will be added to the substrate, what favours the flush process.

root flushing marijuana

And what about enzymes? Could be helpful to use them?

Enzymes are proteic nature mollecules, that catalyze chemical reactions when it's possible. In our case, enzymes used in marijuana growing, the main function is to decompound dead root material, avoiding this way the appearance of phytopathogenic fungi (that could compete for food). Enzymes can also help to promote plant's growth, because the sugars resulting after using enzymes are food for beneficial bacteria like trichoderma.

Some growers use enzymes along flushing period at last stage before harvest. This is a very debatable point, because the process that occur in this type of flushing are not accelerated by using enzyme, what makes us state that the use of enzyme during the flushing is a waste of money.

Where enzymes are trully usefull and highly recommended is along all the growing cycle of plants, because the enhance a better root system health, what will bring better and yielder harvest.

* Important: Never add enzymes in combination with oxygenated water (H2O2), because it generate free radicals that affect proteins denaturing them.

What can I do to avoid substrate from nutrient locking

The answer is easy, the best way to avoid nutrient locking is controlling the EC (ppm) from the nutrient solution used to feed plants. PPM testers are a must tool if we want to know the amount of nutrients we are giving our plants. Even most nutrient brands offer schedules, follow their instructions usually derives in a nutrient-lock. If we want to be sure that our plants will be healthy, the best we can do is to check electroconductivity of nutrient solution before using it. Said this, another important point is to follow a logic when adding fertilizers: Seedlings and Old motherplants don't need the same amount of nutrient. The same way, a plant in early flowering will need less nutrients that a plant in late flowering stage. The best tip we can give is always start with a low dose, and the keep raising it slowly (weekly).

*In some areas when tap water is too hard (too many minerals dissolved, not only chlorine) it is very interesting to use Reverse Osmosis filters. If we only use RO water to preprare the nutrient solution we will know exactly what out plants are eating (only what we've added). This way we will avoid nutrient lockings, defficiencies and toxicities derived from a low quality water.

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