Flushing vs Water Run-off?

[Sledrock]

What is the difference between the Final Flush B4 Harvest and Watering with Plain Water during Normal Maintenance and getting 20-30 Percent Run-Off? Is it that Flushing uses a Lot More Water Thanks in advance for proving your input!

[az2000]

I tend to think of feeding water as "cleansing." Pouring copious amounts of water for 200% runoff is "flushing." I think of the former as being a way to let the plant consume salts in the soil. The latter is a remedial activity when there's substantially too much salts in the soil.

[az2000]

I meant to add: it's not an either/or topic. 20-30% runoff is a "mini-flush." You could dial in your nutrients to the perfect strength, and have 2% runoff (without salt buildup). The rule of thumb is 10% (which ensures no dry spots, and reasonable protection against salt buildup). I do closer to 20% because I think the plants like slightly stronger (over) feeding. I err in that direction, so the 20% runoff helps protect against conditions I know I'm straying into.

So, there's two things involved in the topic: Pre-harvest "cleansing," or remedial "flushing" (which I think even 10% runoff is). You wouldn't have to do even 10% runoff if you have your nutrient strength dialed in perfectly. And, if you did, you wouldn't need as much "pre-harvest cleansing" because there wouldn't be that much stored nutrients/salts (in the plant or soil) to consume.

I think I slightly overfeed, and pour enough volume for 10-20% runoff (to protect against salt buildup). This way I'm more directly impacting the plant each feeding. I can vary things and see more direct results. Pre-harvest, I just feed lighter nutrients the last couple times. I don't do water-only cleanse because I haven't been "force feeding" too much.

So, it's a balancing act. The less you have to "flush" during the grow (the less you overfeed continuously), the less you have to "cleanse" before harvest. Some growers just count on flushing and cleansing. It's just a matter of finding your own style. (Organic "supersoil" growers typically don't flush nor cleanse. The plant takes what it needs.).

[Canuck147]

Well said az2000 - I would only flush if I had a problem - then I would run 6 gallons through my 2 gallon pot. The way I feed my plants is nutes/nutes/flush - flush as in using either plain water or a tea or molasses blend in the water.

[az2000]

I think it's one of those topics new growers can stub their toe on. I continuously "remedial flush" (with 10-20% runoff). Others don't. (You alternate feed/flush. Others do feed/cleanse, i.e., feed/water/feed alternation. Others plan on flushing pre-flower.). It's all the same thing, done differently.

Depending on how effective those methods are, the pre-harvest "cleanse" may need to be more or less effective.

No right or wrong way. Just different ways.

[Canuck147]

Close to harvest it's only plain or the tea or molasses for the last few weeks.

[az2000]

In my case I don't do that. I feed half strength a couple times. Or, water only the last time. (A mild "cleanse." But, I don't overfeed much. And, pour a considerable amount of runoff each time.). I think it's a balancing act. More or less one way or the other. No absolute rule.

[Guest]

I do a final flush without counting gallons...I just test runoff until it reaches 300ppm or lower.

[Sledrock]

I use the GH-Flora trio Nutes, along with Cal/Mag. When I started Flowering, I cut the Micro-Grow in half (added only 1/2 or 1/4 teaspoon? (can't remember what the schedule calls for). (I read, maybe on this site, that during Flowering, the plants need less Nitrogen. I think I cut back on Micro-Grow too soonc though. My last dose of nutes, I went back to the GH's exact recommendation for Micro-Grow and plan to cut that in half again at abour 6 weeks in. (maybe that's what GH recommends anyway?) My Nute schedule is down stairs and I'm too tired to go down and fetch it, I think sometimes I "outsmart" myself and do more harm than good - lol I just don't want my plants to get Nutrient burn (I previously dealt with that problem :-( Anyway, Thanks a bunch for all the feedback, I really appreciate it! BTW, my plants look great right now, I just hope I don't screw them up :-) BTW - I'm growing 2 plants, a GSC and a Cherry Kush in Cocoa Qouir (Sp?)with about 30% perlite in 7 gallon air pots.

[az2000]

The best thing to do is *know* what NPK ratio you're creating (mixing multiple bottles together). If you pay attention to that, you can vary that ratio and "read your plant," find the ratio that works well for you, your style. Then you're unlocked from franchised feeding programs. If you know that GH Flora 3-part creates NPK ratio 1-2-2 (405ppm) in mid flower (which it does), you can then compare other "schedules" in similar terms (or recreate a ratio that works for you using other, generic products).

I have a spreadsheet that lets you see what you're creating when mixing multiple bottles. PM me and I can give it to you. (I don't see a way to attach it here.). To me, it was a gamechanger. Instead of thinking "more of the red stuff, less of the orange stuff," I can know what the plant is receiving (in terms that can be applied to any product, or mixture of products). Once I knew a ratio 1-1.5-2 (230ppm) works well for me in mid flower, I can create that with *any* products. The spreadsheet tells me to add 120pm of this product, 80 ppm of another product, and 30ppm of a third product. If I do that, I get 230ppm of NPK ratio 1-1.5-2.

When you think about it, that's very different than experimenting with cutting Micro & Grow (without knowing what you're creating, or where you were at before you did it). If you know you're at ratio 1-2-2 (to begin with), you can say "I wonder what 1-1.7-2 would be like?" And then mix the bottles to *that* target. Not just guess where you are and where you're going. It's really powerful, I think. It helped me learn to read my plants that way (using a concrete language).