Amended Soil Growers: Don't flush Soil Growers: Flush 1-2+ Weeks Coco Growers Flush: 1 Week DWC/Hydro Growers: Flush for a Few Days. More info about each one in the full tutorial below! 2.) Water plants as normal, except with no nutrients or supplements. You're going to do everything you normally do when it comes to watering, except without any additional nutrients or supplements.
Don't give more water at a time than normal, because this increases the chances of your plants getting overwatered and showing deficiencies/symptoms caused by that problem. 3.) Watch plants closely for signs of too much yellowing. During the flush before harvest, your plant can lose its green color very quickly. Although it's normal to see some amount of yellowing before harvest, it's important to harvest before the sugar leaves on the buds themselves have turned yellow. Although this doesn't affect the quality of the buds, it does affect the appearance and buds aren't as pretty. Additionally, once all the leaves have turned yellow your plant won't really mature a whole lot more, and buds can start to deteriorate quickly. After the flushing period, your plants should appear a lot lighter than they did at the beginning. Read on to get the complete tutorial with more detailed step-by-step instructions!
The idea behind flushing is to let your cannabis plants “use up” any extra nutrients contained in the plant and buds. This way there is a much lower level of nutrients left over after harvest, and it's those extra nutrients that can change the smell, taste or (most often) "smoothness" of your buds in a negative way. So in soil or coco coir, the grower would give the plant just plain water for days or weeks before harvest time. This lets the plant use up the nutrients in the soil/coco, and then – theoretically – start leaching extra nutrients from the buds. The grower simply replaces all the water in their reservoir with plain pH'ed water, and the plant doesn’t have access to any nutrients available except for what’s already in the plant. Flushing is Giving Plants Only Plain Water For Days or Weeks Before Harvest. I used to think that flushing wasn’t that important. I'd still do it most of the time based on habits I'd learned from other growers, but other times I'd skip it altogether. One of the most common reasons growers tell you to flush is that not doing so affects flavor. I’d tried flushing and not flushing, and I personally couldn’t tell any difference when it came to smell or flavor. In fact, I got lots of compliments on the taste and flavor of my buds. My unflushed buds didn’t have a “chemical” taste like others had warned of, and I figured the need to flush was basically a growing myth, or something growers should only do if they’ve given their plant too many nutrients. When it came to flushing, I told myself, “How could the plant be removing nutrients out of buds, anyway?” I also figured that a flush wasn’t needed for my grows since I kept nutrient levels low throughout the entire flowering stage. I thought maintaining lower levels would prevent any type of nutrient buildup (so to speak) in the buds. I still don’t truly know about the science behind flushing or why it works, but after my last grow, my experience has changed my opinion on flushing. For my last grow, I decided to try something a little different…I harvested different plants at different points in the flushing process. While this was definitely not a honest-to-goodness scientific experiment since I was growing different strains without controls, the results of my experiment were more than enough to change my mind. I had one plant I didn’t flush at all, one that was flushed for a couple of days, and one that got flushed for a little more than a week. The plants which were flushed for a few days or a week before harvest were more “smooth” than the buds from the plant which wasn't flushed at all. The buds from the non-flushed plant smelled like completely normal potent marijuana, but they caused me to cough more often during smoking. The buds from plants that got flushed for at least a few days were just plain better. Luckily, you can partially fix harsh buds by curing them for longer – giving buds a little extra time in curing jars will reduce the harshness dramatically, but why not try starting with smooth buds from the beginning? The plants which were flushed for at least a few days yielded buds that came out buttery smooth, without irritating the throat at all. In conclusion, in our insanely informal, scientist-enraging experiment, longer flushing seemed to create smoother buds. As far as we could tell, the taste and smell seemed completely unchanged, so I stand by the fact that, at least in our experiments, flushing didn’t seem to have an effect on enhancing flavor/smell so much as it safeguards it. But the evidence is strong enough to change my opinion and I’ll be flushing for at least a few days before all my future harvests. There doesn’t seem to be any true downside to flushing (as long as you avoid common mistakes like flushing too early) and the potential benefits are worth it!
How to Flush Your Cannabis Plants Before Harvest – Complete Tutorial. 1.) Wait until plant already looks like it’s at the early end of the harvest window – in other words, wait to start the flush until you could pretty much harvest the buds right now if you wanted. At the beginning of the harvest window, your buds should already look just about the way you want them to at harvest. This harvest window lasts for several weeks because marijuana buds don't get "overripe" easily, and you have plenty of time to harvest your buds even two weeks after they've reached the beginning of the harvest window. At this point it would be like harvesting fruit a little early; they won't be at full potential, but they'll still be pretty good, so it's a great time to start the flush now so you harvest at the optimum time. On the flip side, if you start flushing when your buds "seem" two weeks away, instead of already being in the harvest window, chances are you will be starting the flush too early and end up with "underripe" buds (and smaller yields). You can read the full explanation here, but basically buds harvested on the early side tend to be more "racing" or possibly have a paranoia-inducing effect, while waiting longer to harvest increases THC levels and intensifies the psychoactive properties of your buds.
Waiting even longer makes buds that are still potent and psychoactive, but the extra time in the flowering stage also starts to add a more relaxed,"couchlock" effect as some of the THC degrades to CBN. At the earliest part of the harvest window, at least 40-50% of the white hairs have darkened and curled in. If you look at buds under a magnifier, you'll see that the mushroom-like trichomes (which were once clear) are at least half cloudy. A little extra info on harvest time: Cloudy trichomes indicate the highest levels of THC. When half of the trichomes are cloudy it signals the very beginning of the harvest window (the earliest it's ever recommended to harvest buds).