Flushing Your Cannabis Plants – Is the Practice Helpful or Harmful?

As with any area of expertise, there are a lot of things up for debate, and today, we’re looking at one of the more controversial debates among cannabis cultivators. Flushing cannabis plants has become a relatively normal practice, but some people advise against it, saying that it can potentially be more harmful than helpful.

Growers Debate the Pros and Cons of Flushing Cannabis Plants Before Harvest

Here, we’re going to look at some of the perceived benefits of flushing your cannabis plants before harvest and what the possible downsides might be. But first, for anyone who might not be familiar with the idea of “flushing,” the term means watering your plants with plain water, effectively flushing all the nutrients from the soil.

What’s the Best Way to Flush Cannabis Plants?

There’s not only debate over whether or not we should be flushing cannabis plants at all – but also over the best way to go about it.

When to Flush Cannabis Plants

Some growers are adamant that flushing should only be done before harvest—and even then, they often can’t agree on how far ahead of harvest you should start the process. Some will tell you to flush just a few days before harvest, while others will tell you to flush a solid two weeks beforehand.

On the other hand, some people believe you should flush your plants multiple times throughout the cultivation process, but this really only makes sense if there is a mix-up with the nutrients being given to the plant.

How to Flush Cannabis Plants

Yet another topic that cultivators can’t agree on is the actual process used to flush your plants. Some will tell you to use the same amount of water you always do, just skip the nutrients – and for simplicity’s sake and to avoid the risk of overwatering, it’s probably the safest way to flush your plants.

However, some will tell you to use up to twice the amount of water you normally do while slowly decreasing the amount of nutrients by a quarter until you’re using only plain water. Unfortunately, right now, we don’t have any research that can back up the efficiency of one method over the other.

Benefits of Flushing Cannabis Plants

The main reason that people choose to flush cannabis plants before harvesting is to remove the nutrients that they use in the soil still present in the buds being harvested and cured.

It’s also supposed to improve the overall taste of your bud, though that is up for debate among consumers who have personal grows and experimented with both opting to flush their plants or not.

Times that it’s beneficial to flush your cannabis plants before harvest:

• Accidental over-fertilization
• pH imbalances
• Change of nutrient cycle
• Nutrient lockout
• Before harvest to remove added nutrients

Downsides to Flushing Cannabis Plants

If you’ve grown your plants in organic soil, especially if you’re not adding additional nutrients, then you may want to avoid flushing your plants before harvest, as there really isn’t a need for it.

The best scientific data available comes from an Rx Green Technologies study with their own plants, which found that those not flushed were favored for flavor and smoke quality, with no change to yield, potency, terpenes, or mineral content when flushing from 7 to 14 days.

Even if you would normally flush your cannabis plants, there are occasions when you should avoid it because it may cause further damage to an already distressed plant.

Times when flushing could be harmful to your cannabis plants:

• When they’ve been overwatered
• Plants recovering from pest infestation
• Plants stressed by nutrient deficiencies

The Verdict – Is Flushing Cannabis Plants Harmful or Helpful?

According to the data from the Rx Green Technologies experiment, there isn’t necessarily a clear answer on whether flushing cannabis plants is truly harmful or helpful. In fact, flushing did not increase crop yields or THC percentage and made no change to the plant’s terpene profile, so one may wonder if the practice doesn’t do anything of particular benefit.

While flushing nutrients from the plants and soil before harvesting a plant meant for consumption seems sensible, it may affect the flavor of the final product beyond removing a slight mineral-like taste.

Of course, this was a small-scale study done by a single cultivation team, and even though they provided solid data to back up their findings, the data is only preliminary. More research would absolutely be needed to determine whether flushing makes sense for cannabis growers.

Until that day comes, it will probably continue to be just another subject of debate among industry cultivators who want to grow the healthiest and heartiest plants they can.