While some folks have argued otherwise, serious growers have agreed that it is a necessary step. These growers have had the opportunity to experience both sides of the coin on a personal basis and know what it means to flush or not to flush your plants out before harvesting.

The reason for this is the fact that during a plants growing cycle, it stores an excess amount of salts, nutrients and various other compounds. If you don’t allow the plants to have a chance to get rid of these materials before the harvest, you’ll end up with a crop that is bitterer and harsher with a chemical taste. But let’s take a look at both sides for a moment.

Those who are against flushing say that:

a.       Taking nutrients away from plants is counterproductive to the plant’s growth.

b.      Nutrients that are absorbed are permanent and can’t be “used up” by denying more nutrients.

c.       Soil can’t be flushed effectively, so plants in hydro would always taste better if flushing worked.

d.      Plants will stress if nutrients are withheld. This does the opposite of encouraging growth.

e.       No scientific studies have been made regarding the benefits of plant flushing.

Now, we’ll take a look at these claims one by one.

a.       Plant flushing has nothing to do with robbing them of nutrients. Actually, flushing provides a way of allowing the plants to use their excess nutrients that have been built up over their growing cycle. Plants will retain too much of the compounds that degrade taste, smoothness and smell if they are fed nutrients right up till harvesting time. Also, remember, the goal of flushing has nothing to do with encouraging new growth. Flushing actually increases the swelling of the plant’s flowers and buds since the plants are not using energy to draw out nutrients. This is what you want during the last week before harvesting - not growth. 

b.      All it takes is for you to talk to an experienced grower that has encountered “nutrient burn” in order to understand that saying plants can’t expel extra nutrients is completely false. That same grower can also tell you how to fix this problem. This is done by plant flushing and allowing the plants to use their excess nutrients. This concept and principle also applies to the final harvest flush. You’re just allowing your plants to use up extra nutrients.

c.       Saying that soil can’t be flushed is flat out wrong. It merely takes a bit longer than coco or hydro.

d.      While it’s true that stress is placed on plants when nutrients are withheld, it’s also true that (in certain plants) their primary stress defense compounds are the most desirable! With those types of plants, flushing can increase your final product’s resin and essential oil content as well as increasing aroma and flavor. 

e.      Saying that there is not hard science behind the idea of flushing your plants is ludicrous. Scientists are constantly working on determining the best practices for crop cultivation.