Hi, Nico! First of all, thanks for your tips they are very useful! I’m a beginner grower and I would like to ask you some questions about the last weeks of flowering and the harvest period. What is the minimum time for “flushing”? What’s the best way to do this? Should I let the growing medium dry out completely before cutting? When is the best moment to cut? Is it during the “light hours” or during “night hours”?
Thanks a lot for your availability and Happy New Year! –Luciani via the mailbag at NicosNuggets@hightimes.com
Hello Luciani, thanks for reading and writing in.
Flushing is topic that few beginners attempt to breach as there are so many other aspects of cultivation that also need mastering. However, flushing is a very simple technique and you are wise to incorporate it early on in your grow career!
Simply put, flushing is the practice of feeding your plants with nutrient-free water at the very end of her life cycle. Most growers try to use distilled or filtered water to ensure its purity, but the primary concern is that the water is free from any nutrients or minerals such as fertilizers or additives. The goal of flushing is to allow the plant to use up any remaining nutrients in the grow medium or the plant itself before harvest, so that when the plant it cut down she is free from any internal residuals.
Experienced growers will flush for a week minimum, sometimes two weeks. The flushing occurs at the same time intervals that your regularly scheduled watering or feeding would occur – only with pure water, not nutrient solution. To flush longer than a week, you need to ensure your plants are healthy, strong and have received all the necessary nutrients – in ample amounts – during their life cycle. If the plants had a rough start or pests and diseases throughout, it is probably best to only flush for a week so they get a bit more nutrition before cutting them off from your nutrient feeding program.
RO filtered water ready for flushing the garden two weeks prior to harvest.
As far as drying out the medium goes, I always recommend that growers allow their mediums to dry out completely once or twice a week during the flowering cycle. I like to use the following feeding program: Day 1 = Nutrient feeding x2; Day 2 = Fresh water feeding x2; Day 3 = Fresh water feeding x1 + overnight dry out. This helps keep the medium aerated and aids in preventing salt build-ups in the medium that can occur with synthetic…