The Truth About Flushing Cannabis Plants

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To flush or not to flush? There’s been so much talk and opinions about flushing, and after years of trying different methods, the truth can set you free.

This article will cover flushing your soil, coco coir, or hydroponic systems and why you should or should not do so. We will also cover when to flush your plants and what you can add to make the flavor better or push unnecessary salts out of the media.

What is Flushing Plants

Flushing is a process where you add only water or chelated organics at the end of your grow cycle or during the grow cycle. So if you’re running a plant that takes nine weeks to complete, on your last week or so, you can run just water to help the plant think it’s fall season. 

Think about what was just said, fall season.

When you think about how mother nature approaches the end cycle of a season, rain has a lot to do with the process. What do I mean? 

In the spring time, we get April showers which brings May flowers. The water is waking up the soil, and a reaction happens, bringing to life microbes and activating the earth’s soil. 

Mother Nature waters the plants over the summer but nothing like the fall when it’s time to harvest the crop. In the fall season, the rain is constant, and the leaves on plants begin to turn yellow then fall off. Hence the word FALL.

You want to mimic mother nature and create the same season type as an indoor home grower. Vegetation is your spring, Flowering is the summer, and Ripe or the finish is your fall. 

So why wouldn’t you mimic mother nature at the end of a cycle? When I approached my crops in this manner, things started to taste better and make more sense resulting in a dope ass end product year after year.

The truth about flushing organics

The truth is, if you’re growing in organic media, you don’t need to flush your plants as much since you’re using water during the entire process. 

By adding more water in the end of your cycle you trigger the fall type of season and the plant immediately thinks its time to go through its final stages of life. 

Since organic is natural and produces minimal salt build-up, you are clear and can crop your cannabis plants when they are nice and ripe. If you used a tea recipe each week you can follow up with the same process but with more sugar and potassium added to make the plant understand its finish time. 

The upside to organic cannabis growing is the flavor and the trillions of beneficial microbes that help the media to thrive the way mother nature intended. For tips on making your super soil check out our blog covering the easy step to make your mix come to life. 

If you plan to flush your organic soil then keep in mind it will take a lot longer than coco coir or hydroponics since it’s a “heavier” media that can be compounded when adding more water. 

You must give time in between waterings to ensure root rot doesn’t happen. Every 3rd day or when the soil is drying out is the best time to water in the end cycle.

The truth about flushing synthetics

Ok, growing cannabis in coco coir or hydroponics will need to take a different approach than organic cannabis growing. 

Synthetics are high in salts, and when mixed, you will get a chemical reaction that will result in salt formation. 

Coco coir can come with lots of salts in the media so it’s ideal for you to (link to coco coir prep blog) prep your coco coir before you plant anything.

Flushing cannabis plants during the grow cycle is another tip you can take after reading this.

If you are watering your coco coir with synthetics, there will be a build up over time and the salt build up can lead to lockout where the roots aren’t up taking the nutrient provided. 

I like to give a heavy feeding of Flora Kleen once a week to help break down salts and revitalize the media before pounding with more nutrients.

In my hydroponics setups there’s no need to flush in between weeks since the media is root based. Meaning there isn’t a substrate to hold roots in place unless you’re using rockwool and in this case I would flush throughout the cycle.

Most of the problems I see from new growers is the salt build up from the excessive use of nutrients. When you reach the end of the cycle, the plant is suffering from lockout and the uptake of nutrients.

When you reach the end of a cycle in hydroponics and coco coir, you will not need to flush as long since the media is either airy or just roots and the water uptake will be easy for the plant.

A good time period to flush would be 1 week before harvest. 

Now here’s a lil tip:

You can add carbohydrates like molasses, grand finale or catalyst by earth juice to bring out the flavor in the end result. 

It must be an organic chelated product for this to work.

When to Flush Cannabis Plants

You want to flush your plants if a problem occurs, during the growing cycle if using coco coir, and in the end of a grow cycle. There’s a saying I’ve used for 20+ years that states, 

When in doubt, flush it out. 

So if you encounter a problem then you can use a flush method to push out excessive nutrients and by using flora kleen or a product as such, you can remove more an issue a lot faster than just using water. Make sure you have a excessive issue or else you can flush out needed food and damage the plant in the process.


Listen. I know many people have their own way of thinking and growing. Many of us know that growing in organic matter will bring a better flavor but you can get a great result from synthetics as well if you understand how to flush the media properly before harvest.

Not sure if you’ve heard of the ash test where you smoke a joint and take a good look at the ash as the joint burns. If the ash id black in color then the taste will be harsh and not as smooth and thats due to nutrient in the flower. 

If the ash is white grey then the flower hits smoother. I’ve tried this many, many times and the difference is clear. Even if you grow with organic media the process is the same.

I would say that if you use Catalyst or Grand Finale, you get a sweeter taste and a fuller smoke. 

The best advice I can give anyone is try various types of flushing and come up with your own verdict. Try numerous methods and determine which is best for you. You will be amazed at what you find and the end result will help you with your decision. 

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