Article by Jessica Leone, Marijuana Resources
Flushing cannabis involves flooding the soil with water until it runs clean, anywhere between a few days and 2 weeks before harvesting your plant. The question is why? Well, when the marijuana plants are growing, a lot of nutrients are needed to grow them healthy and strong. High nutrient soil is an essential part of that process. The problem is, the same nutrients and minerals that cause the plant to grow well also make the plant problematic to smoke. The nutrients make the bud hard to light and smoke. On top of this, they make the bud extremely harsh to consume. The result is an unpleasant, barely usable harvest, despite the health of the plant.
Forcing a Plant to Use Its Reserves
Flushing cannabis is the process of clearing and removing the nutrients and minerals from the soil. In turn, the plants must use their stored nutrients in order to continue to grow well. This is a little similar to how humans process food. If we eat too much, we store the excess as fat. Then should the time come where there the body is starving for food, it will use the stored fat as energy. When plants do this, they remove the excess minerals right before they are harvested. Flushing cannabis plants forces them to use up their reserves. The result is a bud that is smooth and pleasant tasting.
Healing Nute Burn by Flushing Cannabis
Flushing can also be used to heal nutrient or nute burn. This happens when the plants are overfed too many minerals and nutrients and begin to yellow or burn at the tips. Be sure that your plant really does have nute burn before using flushing as a cure. Many problems can be the cause of yellowing. The flush will also prepare your soil for the next harvest, which helps to prevent nute burn.
The Right Time to Flush
Timing is crucial when determining whether to apply the flushing process. Wrongly timed flushing could drain your plants of much needed nutrients before they are ready. Cannabis plants are usually best flushed 2 weeks before being harvested so if your plant has an 8 week flowering stage, you would begin flushing 6 weeks into that phase. The best way to tell is by looking at your plant’s trichomes, which look like tiny hairs. Once they have all gone from a clear to a milky color, it can indicate that your plant is ready to be flushed.
Switching to Tap Water
Then, instead of feeding your plant with nutrient rich water each day, you simply give it plain water. It’s still important to keep aware of pH Levels and whether they are at safe levels for your plant. Tap water is generally fine for this purpose. At first the water will run through dirty, picking up dirt as it flushes through the soil. Eventually, day by day, the soil will begin to run clearer. At this point you can see that your soil is clear of excess nutrients and minerals. Often plants will yellow a little before being harvested but beware of excess yellowing. This could indicate that you flushed too early.