Marijuana flushing is an important part of finishing your crop, whether you grow in soil, deep water culture, coco coir, rockwool, grow stones, aeroponics, soilless mix, and other marijuana growing systems.
Marijuana is a powerful plant that takes in and stores a lot of what’s in its root environment.
Some of what it stores in its plant tissues are nutrients, heavy metals, and contaminants.
These materials, especially heavy metals and potentially radioactive elements like phosphorus, pollute your crops.
If your crops don’t smell or taste good, if they’re hard to light even though your buds are dry, or if your buds don’t easily burn to a white ash, it means your crops aren’t flushed properly.
One thing that concerned me was when I heard a hydroponics scientist explain that many fertilizers pollute crops with heavy metals.
You hear a lot of arguments about marijuana flushing.
Some people claim it’s not necessary. Or that it’s only necessary if you grow in hydroponics.
In my experience, marijuana flushing benefits the quality of your crops no matter what you grow in.
Yes, marijuana flushing does take up at least a few days if not a week at the end of your bloom phase.
And because you’re no longer supplying hydroponics base nutrients or bloom boosters, you might assume that your marijuana plants aren’t necessarily adding more weight or cannabinoids.
Timing your flushing is very tricky, and it involves having general skills in harvest timing.
YOU WANT TO TIME YOUR HYDROPONICS FLUSHING SO IT MATCHES YOUR HARVEST TIMING.
Read this article here to see methods for cannabis harvest timing.
There’s a narrow window of time when your marijuana crops are at peak late bloom versus when they’ve gone too long and more and more resin glands start going bad on you.
I examine trichomes (resin glands) very carefully using a powerful magnifier starting in peak bloom phase.
When I see 10-15% of my resin glands getting cloudy and/or starting to fall off their stalks, or I see the stalks themselves falling over, I know my buds are nearing maximum ripeness.
It’s a matter of experience with specific strains to know exactly when to start flushing. If you wait too long, your flush will push your buds past their optimal ripeness.
Because you want to cut your buds off when no more than 20% of the resin glands and/or stalks have failed or clouded up, you want to track your resin glands and time your flushing start to match your harvest timing.
I prefer 4-8 days for marijuana flushing.
The number of days depends on what you grew in and what you fed your plants.
Some people believe synthetic hydroponics nutrients create more need for flushing than growing in soil and/or using organic or hydro-organic nutrients.
There’s no evidence for that, but if you use crappy hydroponics nutrients or have been overfertilizing your crops, you might have extra contaminants stored onboard.
The bottom line is you want to run only reverse osmosis water and the marijuana flush formula Flawless Finish for at the last four days to a maximum of eight days at the very end of bloom phase.
Time it so that when your flush days are over, your buds have between 15-20% cloudy resin glands and/or fallen-over resin glands.
Many people make mistakes with flushing, such as they don’t attempt to balance their water pH.
When water has very low parts per million (ppm), as with reverse osmosis water that has no nutrients added to it, it’s hard but not impossible to get your pH to the 5.7-5.9 place that you want it.
Use as little pH Up or pH Down as possible. Be patient. Make sure your pH meter is calibrated. It can be frustrating to pH balance RO water, but it’s worth the trouble.
Many marijuana growers overwater during their marijuana flush.
Remember your marijuana plants are nearing the end of their bloom phase, and won’t be needing as much water as they did before.
In fact, I recommend you start your flush with a regular watering cycle, then don’t water again until the root zone is almost dry.
Of course, if you’re growing in deep water culture or other pure hydroponics where there’s no root zone media at all, you can’t stop watering until the root zone is dry, because your marijuana plants would die.
I recommend that pure hydroponics growers only use one quarter to one half the recommended Flawless Finish dosage, and that they also continue to aerate their water during flushing.
Keep your marijuana flush water in the ideal range of 67-69 degrees Fahrenheit, the same range you use when you’re growing before flushing.
If possible, measure runoff pH and runoff ppm before you start flushing and every time you run flushing water through your crops.
You’ll see ppms decrease as your root zone and marijuana plants get cleansed.
Let’s look at an example of how marijuana flushing works:
You’re growing a marijuana strain that should be harvested 60 days after you put it into 12-12 lighting.
You monitor your resin glands and find that at day 56, 10-15% of them are going cloudy or falling.
That’s perfect. Start your flush and on day 60, do your harvest.
Some marijuana growers even in soil like to do longer flushes, as long as two weeks.
With very long and effective flushes, you’ll definitely see almost all the leaves curl up and dessicate as your plants suck stored nutrition out of them.
My personal belief is that flushing longer than a week wastes crop potential but doesn’t result in cleaner, tastier crops.
Marijuana flushing is important.
People who keep feeding their plants a full dose of nutrients right up to the day of harvest are making a mistake.
Marijuana flushing forces plants to use up what they’ve stored, and that makes for a cleaner crop.
Do marijuana flushing at the right time, using the right flushing product, and the right way, and you’ll enjoy your tastier buds more!