Flushing Plants Before Harvest Is Unnecessary says Rx Green Tech

Star Dog

Star Dog

Well-Known Member
ComputerSaysNo said:
Yes, and because that is 100% true, all the vineyards in the world are dropping water from helicopters every year come harvest season, in order to get the bad minerals out of the grapes; lest they end up in your wine.
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I'm sorry I've never smoked grapes before?
 
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PizzaBob

Active Member
So glad I found this again. When I first started growing hydroponic “tomatos” 30 years ago no one ever heard of flushing. I might have topped of the reservoir for an extra week or so instead of a reservoir change out and hence the EC dropped to like 1.2 from the 1.8 target. That was the extent of any flush I ever did.

Fast forward to the legal days and wow, so many secret sauces and techniques that the bro science experts at the hydro store say are mandatory to produce high quality weed I’m surprised I pulled off a harvest at all. And honestly some of those “tomatoes” were better than what I grow today.

And yeah, lots of hate and peeps don’t want to take the experiment at face value. There’s both subjective and objective components to the study. Yet they focus on just the taste test. Duh! Taste and buzz effects by definition are subjective. But mineral content in leaves is objective.

So for me I’m not worried about a flush. That is if I need to chop I’m not gonna be like OMG I gotta wait 2 weeks. Nor will I be overly concerned about mixing up a new reservoir if I’m close to harvest. Just top it off w water. Since the outcomes won’t really change I’m taking the path of least resistance.
 
Three Berries

Three Berries

Well-Known Member
I just went through a flushing on my flowering plants. Well water, rain water, hi pH water, no change to the runoff pH at all. Still 5.5-5.8.

But the color of the run off went from dark urine color to almost clear today. And the dark urine color when I dumped it in the grass outside the door smelled just like some mammal urine. Must be Uera? But today I'm starting to get the yellow tips so the end of the flushing for me.

I think I need to just water to run off every time with the regular feed.
 
PadawanWarrior

PadawanWarrior

Well-Known Member
Three Berries said:
I just went through a flushing on my flowering plants. Well water, rain water, hi pH water, no change to the runoff pH at all. Still 5.5-5.8.

But the color of the run off went from dark urine color to almost clear today. And the dark urine color when I dumped it in the grass outside the door smelled just like some mammal urine. Must be Uera? But today I'm starting to get the yellow tips so the end of the flushing for me.

I think I need to just water to run off every time with the regular feed.
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What are you feeding them? Do you have to add pH up?
 
Week4@inCharge

Week4@inCharge

Well-Known Member
Horselover fat said:
Uhm, I wouldn't come up with results saying last two weeks of feed is pretty much irrelevant, if I was trying to pump up my nute sales.
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Read it and it seemed like it was endorsing to feed till harvest, that flavor didn't change (between the two studies) of flushing vs not flushing till harvest (feeding). So why not just keep using our stuff.. :)
 
ComputerSaysNo

ComputerSaysNo

Well-Known Member
Week4@inCharge said:
Read it and it seemed like it was endorsing to feed till harvest, that flavor didn't change (between the two studies) of flushing vs not flushing till harvest (feeding). So why not just keep using our stuff.. :)
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They made no recommendations either way. They said that the taste panel slightly preferred flowers from plants that were fed until harvest.

The main result of the study was: flushing in the sense of stopping to feed has no significant effect. Seems like a good way to save a few nutrients.

I've decided to not give a damn in my grows and I'll just feed right to the end, with either flowering or late-flowering nutrients. Keeps things simple.
 
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budtoker221

Well-Known Member
What is the most typical hydro or dtw style nutrient regimen for the last weeks flower before harvest?
Do most people taper off the bloom /P in the last weeks to a lower level NPK,?

For example here’s a general hydroponic trio feeding schedule from the website sensigarden:

“Early Flowering – 4ml/gal FloraMicro, 3ml/gal FloraGro and 5ml/gal FloraBloom

Peak flowering – 3ml/gal FloraMicro, 1 ml/gal FloraGro and 8ml/gal FloraBloom

Flush – 2.5ml/gal of each part for three days, then FloraKleen if growing in coco coir or soil perlite mix.Follow up by plain RO water or de-chlorinated water w/ one tsp/gal (2.5ml) of molasses if you so desire.
“

This website suggests actually bumping up the floragrow component during the first 3 days of the “flush” period

sensigarden.com

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ComputerSaysNo

ComputerSaysNo

Well-Known Member
They suggest something that amounts to flushing, which means they're following a cargo cult, at least they haven't tested their method systematically.

The numbers that they give are much too high for GH nutrients. If you feed that you will burn a lot of strains.

What they suggest as a "flush" is the regular schedule that I feed through the entire transition and early flowering phase (apart from the fact that flushing is not necessary in the first place).

FloraKleen (FlashClean) is good for getting nutrient deposits out of the medium, e.g. when changing the feed or after overfeeding. It's not going to do much if anything as a pre-harvest treatment, but it can be useful to clean the equipment and the medium if you want to reuse it.

GH(E) sell a late-flowering fertilizer called "Ripen" (FinalPart) that you're supposed to use in the last 10-15 days exclusively. It contains no nitrogen; I have no idea if it's worth using.
 
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budtoker221

Well-Known Member
Yea I wasn’t going to use the floralclean product but was considering following the rest of the protocol on that website, but if the numbers are too high than maybe the Lucas formula all the way through flower but cut in half the last week or so? Or just go from full strength Lucas formula to water for the last week?
 
ComputerSaysNo

ComputerSaysNo

Well-Known Member
budtoker221 said:
Or just go from full strength Lucas formula to water for the last week?
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I have no experience with Lucas. I'm using GHE nutrients (which is the European part of GH, now independent and changed their name to "Terra Aquatica" after GH was swallowed by some Big Ag). The formula of GH and GHE appear to be the same.

The schedule suggested by GH will burn the plants (it has happened to me), and growers experienced with them suggest going with half the listed numbers. That has worked very well for me.

Lucas 5/10 for GH is quite close to what I feed, 8/16 seems a tad high, but since there's no "grow" in it, it might be OK. It works for a lot of people.

Going to plain water in the last week should be OK. Applying FlashClean (FloraKleen) will probably not do much, but it's good if you want to rinse/clean the system and medium. It's also good if you have overfertilized or want to change nutrients, to get the nutes out of the medium quickly.

Their formula for FloraKleen is secret, so it's impossible to know how well it works and why.
 
ComputerSaysNo

ComputerSaysNo

Well-Known Member
Three Berries said:
Here's the MSDS for the Florakleen. ph of 4. Doesn't say what it is though.
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Yes, it's a trade secret and they don't have to publish that information on the safety sheets.

pH of 4 makes sense, it does lower water pH by quite a bit at the recommended dilution (my tap water is close to 8 and I don't have to use a lot of pH- with FlashClean to get to 6).

It faintly smells of "cleaning product", but not in an unpleasant way.
 
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