How important is flushing your cannabis plants prior to harvest? Very important! Failing to properly flush your plants prior to harvest will not only result in horrible-tasting cannabis, but will also be harsh when smoked.
Let me tell you a quick story. A friend of mine (who is a beginner grower) gifted me some cannabis from his first ever harvest. Was it potent? Yes. Was it grown well and did it looked well trimmed? Absolutely. Did it taste like garbage? Yup, it tasted like garbage because for whatever reason my friend failed to flush his plant prior to harvest. As I was smoking a joint of it, I could taste all of the nutrients and it tasted harsher than normal. After that, I put some of his weed into a vaporizer. Big mistake. I could really taste the nutrients then. For those reasons, it’s important to flush your cannabis plant prior to harvesting it. We say flush, as in, flush out the system. Flushing is known among more old school growers as leeching; meaning leeching out the residual nutrients left over in the plant from all of the supplemental fertilization that you do throughout the grow.
You have to do a flush unless you have grown your plants with no nutrient additives. It's straightforward, just give your plants lots of plain water and go for pure water if it's not too much trouble in your case. Start giving your plant plain water at least a week prior to harvest if you are using soil. Some growers start flushing two weeks prior to harvest. Do not start flushing more than two weeks prior to harvest or you may actually hurt your yield. If you are growing hydroponically, you can get away with starting the flushing process only a few days prior to harvest. Do you still need to pH correct your water? Yes, you do still need to PH correct your water. You should also be significantly increasing the amount of water you give your plant during this phase. Beyond using a pH control kit, I wouldn't put anything in the water. There are so-called flushing solutions that expedient the leeching process, although, unless you've missed the flushing deadline of a week or so prior to harvest, then you likely don't need any such solution.
The leaves of the plant can also be flushed and disinfected before harvest in various ways. That would be considered an advanced method of flushing. Basically, applying UVC light to a plant during the flushing phase can help in preventing molds in the post-harvest curing period. You can also mist the plants with a spray bottle that contains pure water for additional disinfecting and flushing. This is especially useful if you've used any sort of canopy sprays on your plant in the recent past. There are also various disinfectant spray solutions that involve mixing a low concentration hydrogen peroxide into the water. Although, the average grower doesn't need to go this far. For the amateur grower, if you've cut off your nutrients a week prior to harvest and you are watering with large volumes of plain pH-corrected water, then you are doing a bang up job with your flushing. Keep in mind that there are several different flushing techniques used by a wide variety of growers. This article covers just a few of those techniques. What technique do you use for flushing? Let me know by leaving a comment below!
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