Why, When & How to Flush Cannabis Plants

Why, When & How to Flush Cannabis Plants- WeedSeedShop

If you want your final product to be a smooth smoke with a very fine flavour, then don’t forget to flush your cannabis plants. It’s a necessary step in any cultivation process. Keep reading this article for exactly when and how to flush your cannabis garden!

Flushing is one of the crucial steps in the growing process that a lot of newbie growers neglect, and this can really affect the final product. The process of flushing is simple, easy and it can make all the difference.

To avoid an extremely harsh smoke and a somewhat disappointing flavour, flushing is necessary. It can be the waste of a really good grow to skip this fundamental step. So, to know exactly why, how and when to flush your plants, keep reading!

Why should you flush your cannabis plants?

Why, When & How to Flush Cannabis Plants- WeedSeedShop

Flushing is the act of watering your plants with water that is completely without nutrients. It is essentially giving your plants so much water, it comes out of the bottom of your pot looking (basically) clear. The water you use for this doesn’t contain nutrients, and this is what allows all of the nutrients to flush out.

It is the way to get rid of any nutrients that are left in the plant material before you harvest. The reason you might want to get rid of any residual nutrients that haven’t been used is because they interfere with the taste and smoking experience in the end. We will explain exactly how to do below.

There are other reasons why it is beneficial to flush your plants throughout their growth, too:

It is good for your plant to be a little bit malnourished every now and then, as it encourages the plant to be able to absorb nutrients well. Flushing also avoids an excess of nutrients building up in the plant, otherwise known as nutrient burn.

Essentially, flushing causes the plant to use up any remaining nutrients in the soil, and therefore in the plant itself. Timing this perfectly will mean that your plants will have no nutrients in them at the time that you harvest, meaning the flavour will not be tainted!

When is the perfect time to flush your plants?

If you accidentally overfeed your plants, that is a really good time to flush them. You will notice that the tips of the leaves begin changing colour and shrivelling up. This is the indication that they are experiencing nutrient burn. If you notice this happening during the vegetative state, then you can flush them (watering with water not containing nutrients). You will notice the leaves go back to normal, and then just give them some time before adding any more nutrients! Flushing can cause some extreme stress to plants, so pay close attention after you’re done flushing.

Why, When & How to Flush Cannabis Plants- WeedSeedShop

When it comes to the final flush, it should take place just a couple of weeks before harvest. To be more specific, as it will change from strain to strain, you can pay attention to the trichomes. When trichomes first appear, they appear as clear crystals. After some time, they will begin to turn a milky or cloudy colour.

The moment they start turning a milky colour is the best time to start flushing your plants. The trichomes will start turning amber by the time you harvest, and if you haven’t flushed by then, you should! But it is better not to wait until they have turned amber so that you really have a chance to flush your plants properly before harvest.

The closer attention you pay to your cannabis plants, the easier it will be to decide when to do the final flush. If you do it too soon, your plants could end up being unhealthy, and if you do it too late you might not enjoy your final product. So, be mindful and use a magnifying glass if you have to – to get up close and personal with those trichomes.

Exactly how do you flush your plants?

It’s much simpler than regular watering! Whereas throughout the grow you water your plants with nutrients, for flushing all that is required is untreated tap water. The thing to be mindful of is the pH level of the water that comes out of your tap. You are generally looking for a pH of 5.5 – 6.5, so aiming for an almost neutral pH of 6 is a good target.

Give your plants untreated water with pH of 6 until it starts to run out of the bottom of the pot they are growing in. You’re aiming to flood the pot with as much water as it will carry. The water that comes out of the bottom should look dirty because of all the nutrients in the soil. Keep flushing until the water comes out almost as clear as you put in.

It is good for growers to keep a TDS (total dissolved solids) meter in their toolkits. Your aim for a perfect flush is around 50 ppm and if not, then the same reading as the water you put in initially. On the first round, you might get a reading of around 1300. As you can imagine, it might take a few rounds before you get down to 50.

Now it’s time to harvest, dry and cure your buds. Flushing will have successfully removed any nutrients, including chlorophyll that might be living in the soil and in your plant. You can now look forward to a deliciously smooth smoke!


1 thought on “Why, When & How to Flush Cannabis Plants”

  1. So if I’m bottom feeding my plants , in the final couple weeks , can I just stop the nutes and continue to bottom feed them straight water till harvest ?

Leave a Comment

Your email address will not be published. Required fields are marked *


  • Author_profiles-WSS-Emma Ryte

    Emma Ryte

    Born in Germany, lived in England my childhood years and spent my high school era in the US. My parents are basically hippies and that is why I have had the possibility to speak freely and explore my passion for the cannabis plant. My love for writing followed soon after. Writing about this subject has taught me so many things about the use, cultivation, health benefits and industrial options, and I love that I can share this knowledge with you! I visit Amsterdam as often as I can and I love the vibe there when it comes to weed, it lets me try new things and learn about the newest developments in the industry. The one person I would love to smoke some with would have to be Stevie Wonder. I love relaxing to his music while high and I would love to meet him!
    More about this author
Scroll to Top