Flushing Marijuana Plants Before the Harvest

flushing cannabis

Flushing cannabis is easy and a free method that might improve the smoothness and quality of your marijuana buds before harvesting. However, cannabis growers should also be cautious with flushing before harvesting because if you do it too early, it can cause damage to the quality of your buds. The process of flushing marijuana plants involves giving your cannabis plants just simple water with no nutrients for a period of time before harvesting. For the cannabis growers who usually give water to their plants with nutrients in it, you will water your cannabis plants as normal with the same kind of water you usually use, but you don’t add extra nutrients. Based on the setup, cannabis growers normally flush their cannabis plants this way for a few days up to around 2 weeks. 

What is flushing?

Flushing is the method of removing excess nutrients from the solid of your cannabis plants with natural water. Water is an amazing powerful element, and it could do wonders for your cannabis plant and from simply feeding your plants. It could flush away the excess minerals and nutrients, allowing the plants and soil to be fresh again. Taking away the nutrient isn’t a bad idea, but actually, it is very beneficial to you and your plants. Flushing away minerals covers the way for the roots of your cannabis plants to take in any residual nutrients in the soil. You need to flush your cannabis plant in a short period of time before the harvest so that plants do not have enough time to become unhealthy. 

When to start flushing cannabis?

When to start flushing cannabis or when should you start flushing cannabis? The ideal time to flush your cannabis plant is around 2 weeks before you plan to harvest your plant. But, this time doesn’t work perfectly for all cannabis strain and growing setups. And when it is time to harvest itself, monitor the trichomes of your cannabis plants, they will demonstrate which plants are ready to harvest.  Cannabis plants that have mostly icy trichomes and only have some that are white and milky are too early to be harvested and are perfect to be flushed away. For instance, 2 weeks after the big flush, you want most of your trichome to have already changed color, this could be tricky, mainly for newbie growers, but it’s important to think about yet.

How to Flush Your Cannabis Plants Before Harvest

  • Wait until your cannabis plants already look like it is at the early end of the harvest window

At the start of the harvest window, your buds must already look just about the way you want them to be harvested. This harvest window only lasts for a few weeks because cannabis buds don’t get “overripe” easily, and you have a lot of time to harvest your buds even just after 2 weeks after they have reached the start of the harvest window. In this case, it is just like you are harvesting fruit a little early; they will not be at full potential, but they will be still good, so it is the best time to begin flushing marijuana plants, and when you harvest at the right time. On the other side, if you begin flushing once your buds are just 2 weeks away, rather than already being in the harvest window, chances are you would be starting the flush too early and would end up with “under-ripe” buds and smaller yields. At the premature part of the harvest window, at least 40 to 50% of the white hairs have curled in and darkened. If you take a look at the buds under a magnifying glass, you will see that the mushroom-like trichomes are at least half cloudy. 

  • Provide only plain pH’ed water to plant until harvest (from a few days to 2+ weeks)

You are going to do the thing you usually do when it comes to watering, but without any extra supplements or nutrients. Don’t give more water just like normal watering, because this increases the possibility of your cannabis plants getting overwatered and showing symptoms caused by that issue.

Soil Growers Flush 1-2+ weeks – soil cannabis growers must flush the longest, from 1 to 2 soil growers who have not used any nutrient from seeds to be harvested, you do not have to think about flushing marijuana because you have been giving simple water from the start. The microbes in the soil have sustained nutrients straight to your cannabis plant as it’s required, and it is very unfortunate that you got any kind of nutrient. 

Coco Growers Flush – 1 Week – coco coir doesn’t hold into a lot of additional nutrients and just watering or two with simple water would flush most nutrients away. So, cannabis growers who are using coco coir must flush their cannabis plants from several days around a week, based on how quickly the cannabis plant is changing its color to yellowish. 

DWC/HYDRO Growers Flush for a Few Days – when DWC/Hydro growers change their tank to clear water, their cannabis plants have obtained almost zero nutrients instantly. And because of that, a hydro cannabis grower must normally flush their cannabis plant for a few days before harvesting to avoid early yellowing. 

  •  Watch out for early yellowing

It is important to monitor your cannabis plants during the flush before it will be harvested. Your cannabis plant could change its color to yellow overnight in precise situations. Even though it is normal to see some amount of yellowing before harvesting, it is important to harvest before the sugar leaves on the buds have changed to yellow. And if the leaves of your cannabis plant are turning to another color like purple or red, that’s also a signal that the end is near. Even for cannabis plants where leaves are changing colors is normal, it usually happens when harvest time is near.

Your cannabis plant cannot really make energy from light after the leaves stop from being green. This means that you must plant on harvesting within a week, because the leaves are turning into complete purple, and possibly even sooner if the bused begin the discoloration. Try to harvest the buds before the sugar leaves and the buds itself actually begin to turn yellow. Even though discolored sugar leaves do not affect the potency of the buds, it does affect the looks. In addition, when all the leaves are yellow and your buds won’t really mature, buds could quickly worsen the loss of potency and in health. 

Flushing Tips

Flushing Too Early

The biggest problem in flushing cannabis, especially for newbie growers, is to begin the flushing too early. Newbie growers usually think that their cannabis plant is just a week or two from harvest time when the truth is it is 4 weeks or more away from the ideal harvest time. Cannabis breeders sometimes emphasize the length of the flowering stage for a cannabis strain, giving the timeline for the fixed earliest harvest, so it is completely a great idea to add extra 2 weeks to their suggested time for a more practical estimate of the ideal time to harvest. 

When you’re flushing marijuana plants too early, you are slowing its growth because the buds are not getting enough nutrients to develop properly. Without being given the correct amount of nutrients during the most critical part of the flowering period, the weight, potency, and the quality of your buds could also be lower. 

Problems with Flushing Too Early

  • Growth is stopped during the major parts of the flowering period, and yields are reduced.
  • Potency might be lower due to the buds that didn’t have the nutrient needed to develop THC properly, and if the buds are also being harvested early it decreases the potency ever farther. 
  • As the plant left too long without nutrients begins developing nutrient insufficiency that could spread to the sugar leaves on your buds, the appearance of your buds could be affected, causing displeasing yellow leaves. Even though this does not negatively affect how the bud smokes, taking care o

The looks of the buds could be affected, as the cannabis plant left too long without any nutrients begins developing nutrient insufficiency that could spread to the sugar leaves on your cannabis buds, causing displeasing yellow leaves. Although this doesn’t negatively affect how the bud smokes, taking care of your sugar leaves until harvest is very important to get the best-looking buds. Flushing cannabis too long or too early could hurt the appearance of your buds because it could cause the sugar leaves to begin to turn yellow. All nutrients were used in the plants including the one in the sugar leaves, causing displeasing yellowing on the sugar leaves that is almost unfeasible to cut off. Permitting this to occur gives your buds coated with a little yellow area where the base of the leaves was before they got cut off. These buds that don’t have yellowing have an entire higher-quality appearance and more obvious that it is so important to flush. 

Not pH’ing Your Water During the Flushing

This other usual problem cannabis growers have is they end sustaining pH once they begin the flushing. And even in flushing, it is important to keep the pH at the roots to ensure your cannabis plant could properly use the nutrients accessible. It could help avoid yellowing and spots on the leaves during the flushing and once the pH is too low or too high at the plant roots, it makes particular nutrients inaccessible to the cannabis plant and increases the possibility of seeing nutrients insufficiency. The cannabis plant also opts to absorb more salts and aluminum out of the water one the pH is not in the right range. Keeping the pH during the flushing would help avoid insufficiency and unwanted salt absorption, whilst still permitting your cannabis plant to utilize its additional reserves of nutrients in the buds. 

Harvest without flushing

Is it okay to harvest without flushing? Yes, because in the recent study, flushing before the harvest time might not improve the quality of the marijuana flower. However, the result may seem contradicting the usual belief that flushing improves the burnability of dried marijuana flowers and its taste. But according to Danny Danko senior cultivation editor at High Time “Flushing is important, because it removes the excess nutrients that are leftover within the plant, then it helps with the burnability of the flower by leaching out excess nutrients and salts”. Flushing has no benefits, participants in the recent study prefer the taste of the cannabis flower that has not been flushed at all, the duration of flushing doesn’t affect the flavor, color or the ashe, and the smoothe of the smoke. Therefore, it is okay to not flush your cannabis plants before harvesting because it doesn’t have benefits after all. 


There is no truly correct answer when we talk about flushing marijuana plants. No one has done this kind of endeavor and it will take to be able to stay with the authority the great way and time to flush, what the exact effects would be or if it is even worth it.

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