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**GreenhouseEffect** · 03-31-2018, 09:48 AM

I ph down with vinegar in soil, and it has not caused a problem, but I get the surface good and dry in between, never grew in/ or tried it with coco though.
I think PH down is supposed to have some cal mag in it? So could affect that?
I have used Diatomacious earth, yellow sticky cards, and traps to get rid of gnats before. Drill holes in a plastic jug and put a mix of cheap apple flavored dish soap and water in the bottom, to make the traps. The apple is more attractive than vinegar to them.
The dry soil surface is the best deterant, but don't think you should do that with Coco?

**DoctorJohnson** · 03-31-2018, 10:29 AM

So I assume that you are growing outdoors? If indoors, you just need better screening or whatever to keep gnats out in the first place.

If you are going through a lot of pH Down, you will go through a lot of vinegar too. I would think that plain old distilled white vinegar (which is petroleum based) would be cheaper than cider vinegar and that yes, not having the fruity component might help keep pests away. But I think gnats are just attracted to wet soil regardless. You can put a inch thick layer of perlite over the top of your coco to try to keep them away. I have sprayed Bayer Neem Oil on my coco outdoors to get rid of gnats, just FYI...

People do use vinegar successfully. I never have, but I have seen a lot of people on the forums who do.
Just a thought: if your water requires that much pH Down, maybe just switch to RO water? But then you might need to start adding cal/mag. It's always something...

pH Down doesn't have calcium or magnesium, but it is a source of phosphorous. (The P in NPK.)

**DoctorJohnson** · 03-31-2018, 11:36 AM

Well I would expect that you should be able to keep the evil little buggers out of your coco indoors with just screening or other isolation measures. One other thought: do you have house plants? They can be a reservoir of fungus gnats. Even a bag of soil stored outside can get infested and bring the problem indoors. And of course if you put your pot plants out in the sun you risk infection.

You can buy reverse osmosis water at the grocery store in jugs, or I see that a lot of people fill their own jugs from a machine at WalMart(?) Cheaper? You don't need to go to 100% RO but can mix it to get the PPM down where you want it. I'm curious how many PPM your well water is. But that's all academic since your water works well for you and you just need to reduce the pH...

**Spanky** · 03-31-2018, 03:45 PM

Hi L. I have a full bottle of Up. Never needed it! Wanna trade!

There are so many interesting opinions about pH in coco. Some are adamant that pH in should be whatever is needed to get 6.0 in your run off. Others feel coco reverts to the pH it wants to be and they don't bother to test the run off. I have two plants right now. Through the whole grow, one needs 5 or so in and always comes out 6.5. The other must have 4 or so in to come out 6.5. If I vary the latter it always comes out 7 or more. I'm not necessarily trying for 6.5, they just come out that way unless I am way off on what goes in. So, I have given them what they seem to want and everyone has stayed green and healthy. These are from March 24. How do they look to you?!

**BlueBudz** · 03-31-2018, 04:36 PM

Apple cider vinegar will absolutely attract bugs, it’s commonly used for this. White vinegar is the opposite, you can use it to deter bugs. As far as using it to adjust PH I have no idea but if it works it would be a lot cheaper then down!

**Paracelsus** · 03-31-2018, 07:39 PM

BlueBudz Hit the nail on the head. I don’t use coco I use organic no till garden soil NTG So pH is moot for me. What I do use is organic apple cider vinegar in a small jar right next to my plants under the light. It attracts the little fuckers and the stupid shits drown in it. Ha!

**DoctorJohnson** · 03-31-2018, 08:48 PM

> Indoor water has a softener system that is salt. My plants don't like that. Outside faucets were by passed. That's enough hauling for me. I could tell you ppm if I knew of what?

The fact that you have an NaCl ion-exchange water softener system pretty much answers the questions "How much?" and "Of what?" at least in very round numbers (as in "Lots of calcium carbonate!"). It's true that your plants would like the sodium replacement ions even less. You may very well not actually need to be adding cal/mag (unless it is all crashing out of solution when you lower the pH).

Anyway, this is all academic since you are having success. Still, if you are the curious/experimental type, a PPM meter is cheap and it would be interesting to know exactly what levels you're dealing with. Anything over 100 PPM is hard, and it's not uncommon for people in places where ion exchange systems are common to have levels over 300 PPM. And levels of Ca++ and Mg++ that high can affect the level of other positively charged ions. That's why General Hydroponics makes a special version of their FloraMicro (called "FloraMicro Hardwater" appropriately enough) just for people like you who have very hard water. It might be interesting to look into that too.

You're using well water, so the water numbers from your local water utility's website aren't immediately relevant for you, but I'll bet they show a lot of hardness too as the region probably has water flowing over limestone rock. Again, if you are the curious type you might want to have a look... You in southern California by any chance? Some of the water there is so hard it's liquid concrete.

**Locrian99** · 03-31-2018, 08:59 PM

I’d love to see a few pics of the amazing plants you must grow doctorjohnson. You sure sound like you’ve got everything perfected.

**DoctorJohnson** · 03-31-2018, 09:08 PM

> There are so many interesting opinions about pH in coco.
A whole lotta ignorance and folklore too. What's really important for coco is to make sure that you wash all the salt out of it. I have had two bricks (different brands) of coco that said "triple washed" and all that, and the first wash was still 1000 PPM! Wash your coco thoroughly unless you are positive it's clean. (Again, a PPM meter is a great, cheap way not to be flying blind.)

FWIW, my recirculating nutrient coco system pumps GH FloraSeries + CALiMAGic in every morning at about 315 PPM and pH 5.9 and it runs off at about 215 PPM and pH 6.2. But those numbers vary a lot as the recirculating nutes are used up over the course of a week. What I recommend for the curious and the capable is to keep a logbook throughout each grow. That will teach you a lot about how your system works, what your plant likes and does not like, and how to optimize.

Or you can just give it mild, un-pH'd nute solution, drain to waste, and cross your fingers. If your coco is well washed, you should get great results with that, too. You just won't know as much about what's going on and will be that much less able to optimize and troubleshoot.

Time to go tend to my tomatoes again.

**DoctorJohnson** · 03-31-2018, 10:22 PM

Originally posted by Locrian99 View Post

I’d love to see a few pics of the amazing plants you must grow doctorjohnson. You sure sound like you’ve got everything perfected.

Snark snark?

Hard to tell...

I have never claimed to have everything perfected, and I don't by any means. (For all of my obsessive measuring and record keeping, I just burned the tips of the leaves of my White Widow.) I have never had a grow in which something didn't go wrong, from horses trampling a guerrilla grow to dropping lamps on plants to mixing fertilizer wrong to name a few.

Most of why I'm here is to learn from others as equipment, strains, and techniques evolve amazingly quickly (and because I enjoy the grower community--they are an interesting bunch).

I have been growing pot off and on since 1970 (Mexican bag seed under fluorescent tubes or sunlight back in the day..), have a degree in biology (among others), and have designed and built scientific instruments (including pH meters and light-measuring instruments) in a university bioengineering facility (among others), so I do think that I have some ideas and knowledge to offer. I can remember when LEDs were invented...

I don't always have a lot of time so sometimes my posts are a little terse. I hope they don't sound abrupt. I apologize if I come off sounding like a know-it-all. I don't think I do, but your comment makes me wonder. Maybe I should just bugger off and leave the newbs to share their discoveries about the wonders of molasses, 48-hour dark periods, and so on. Nothing wrong with that. We used to pour cognac into our baggies of awful weed because word was that it made it stronger (in the days when you had to smoke and entire joint by yourself to catch a buzz). Or add dried banana peels. Or eat roaches...

When I started growing, the only source of information was an eighth-inch-thick, 8 1/2 x 11 booklet you could buy from under the counter at the hippy plant store next to the university. (Canary yellow cover,"How to Grow Marijuana Indoors" or something like that.) For the first 20 years I had to learn almost everything by trial and error (I mean at the level of "girl plant good, boy plant bad.") So a website like GWE and endless YouTube videos (to say nothing of feminized seeds and autoflowers!) seem like a Godsend. And living in a state where it's now legal to buy, grow, and smoke weed? I never, ever would have guessed that would happen in my lifetime back in the Nixon era.

But you wanted to see pics of my plants. Here's the White Widow I'm growing in a 2' x 2' tent here in the corner of my tiny midtown apartment. It's my first SCROG. The six black hoses feed nute solution from the manifold on the right. Six gallons 70% coco coir / 30% perlite sits in a homebrew air pot, a plastic mesh wastebasket lined with burlap on top of a six-gallon reservoir into which the nute solution drains after the pump runs for two minutes every morning. The goal was to free me from having to water the plant every morning and not to waste all those lovely nutes by sending them down the drain every day. So far it's working great, but I still go in and fuss with the leaves and flowers every day--the good thing is that now if I need to leave town for a week, the plant can run on autopilot.

If you were expecting a 1000 square foot facility with flowers the size of 40-ouncers, that ain't me. Even with my very modest setup I have enough bud, tincture, CannaCaps, and rosin for me and a few friends, but then I'm nowhere near the stoner I was 40+ years ago...

That's my story, Locrian. I hope you enjoyed it. What's yours?

White Widow after some vigorous training for SCROG. 6 gallons coco coir with 30% perlite

White Widow budlets

**Spanky** · 04-01-2018, 08:33 AM

Except my waste, like everything else that is biodegradable, goes into my outdoor compost bins. With a passive solar, net zero home, heated by a masonry heater (sourced locally!) with fuel from our 32 acre woodlot that we manage for bear, moose, birds, amphibians, conserved forever against development, and indoor grows powered exclusively by the sun, we are a little aware of environmental concerns.

**DoctorJohnson** · 04-01-2018, 12:43 PM

Hi Spanky -- Like Paracelsus referred to, growing in coco is generally thought of as hydroponics but in a non-nutritive matrix (coco fibers) that lets more air get to the roots, and I have really got religion about letting air get to the roots! Air pots! Perlite!

I had amazing results using hydroponic deep water culture, but the pH in the reservoir was all over the place. (I mean dropping into the 4s overnight--emergency type instability) I think now that was because my reservoir was too small, but the people who use Advanced Nutrients pH Perfect line tell me that it really does keep the pH stable so I'll try that if and when I do another hydroponic grow.

Anyway, in an effort to get around that pH stability problem (and just out of curiosity) I decided to try drain-to-waste coco, and it worked wonderfully! Dead simple! Just mix a batch of nutes and pour enough on the plant every day to get about 10% runoff and that's it! I didn't even bother to pH the nutes since the GH FloraSeries mixed up at about pH 6 all by itself.

Oh I did make one change, Nebula's coco article (which is great, as always) says to fertilize one day and then give a day or two of just water. From my orchid growing days I remembered the mantra of "fertilize weakly weekly"--that is, give them a steady diet of diluted nutes rather than a feast-or-famine regimen. I did the same with my coco grow and fed every day but with very dilute nutes (200 PPM from Ca/Mg for our very soft water here, plus GH FloraSeries per Nebula's feed chart but diluted down to only about 400 PPM total--any more than that was too much for daily feeding. That worked great.

The two downsides to drain-to-waste, as I mentioned earlier, were that a) you have to water EVERY DAY with coco, so no vacation, no business trip, dairy cows never know it's Sunday... And b) I didn't like pouring all that perfectly good fertilizer down the drain every day.

So as I said, I put the plant on top of six gallon reservoir (made out of a plastic storage container) and used a cheap, in-aquarium water circulation pump on a timer to pump water up to the plant every day. I knew it would work since it's essentially the exact same thing as DWC hydro only the plant has its roots in coco (so more air I'm thinking?), not the reservoir. I was even able to use the same nute mix as I had used for drain to waste.

Here are my last few reservoir readings. 200 PPM of each reading is from Ca/Mg, so you can see that it's really diluted. 400 PPM is the highest I can go, where tip yellowing starts, and 270 PPM is the lowest it can get, where a pH crash can occur and (I suppose) deficiencies can appear if left long enough.

Day	pH	PPM
Thur	5.9	322
Fri	5.9	316
Sat
Sun	5.9	300

Like everyone, I have worked out a system that works for me over a multiple grows. It may not be best and it may not work for everyone, but I'm getting good results.

> Do you collect the runoff and give it to the plants over and over?
Yes. I change the GH FloraSeries nutes weekly (advancing to the next feeding ratio in Nebula's chart ("Early Bloom," "Mid Bloom," etc.), though as the plant gets bigger, I find myself having to top off the res mid-week sometimes. I"m at six gallons now and would like to use 10 next time... (The spent nutes go on the houseplants sometimes.

)

> Does the pH change when this happens?
Yes, it rises slowly, but not a lot (see chart below). The PPMs steadily decline, though, which is pretty cool to watch! The plant steadily extracts the fertilizer from the nute mix every day!

> Does any salt build up go into the water and hence, back into the plant?
Well, the nutes are salts technically speaking, but no, they stay in solution and I see no "salting up" of the coco and as I said in the previous paragraph, the nutrient levels go down every day.

> Do the nutes "spoil" if kept for more than a day or two?
In my opinion, a clean mix of nutes (which are just salts, right--nothing organic to break down) should be stable for weeks if kept clean, cool, and away from light, but the manufacturers all seem to agree that you shouldn't keep mixed (i.e. diluted) nutes around for a long time. But more to the point, nutes in a dark, aerated/mixed reservoir, are perfectly stable for a week. That's exactly what hydroponic fertilizer is made for!

> How do you control the humidity when keeping so much liquid in your grow space?
That's a big issue this time with a six gallon air pot in a small tent! I have an intake fan, a circulation fan, and an exhaust fan, so I'm constantly turning over and circulating the air. I was giving it 24 hours of light when it was in veg and watering it three times a day. Now it only gets one watering in 12 hours in an attempt to get the RH down. I am curious to see how my flowers do ripening at 60% humidity. I think I have enough air circulation to be OK, but I don't know. (I had a prize bud full of mold once and it broke my heart.) Oh, I have also lollipopped the understory and defoliated the flower layer of the SCROG, so that helps circulation and limits leaves from touching leaves where droplets occur.

> I had a few cal/mag deficiency leaf symptoms early on, so I just do 5 ml per gallon with every watering now and no more symptoms. I'd rather use the cal/mag than take a chance on messing things up with only my second grow. If I reused my runoff, how would I know if the plant is getting enough cal mag?

I follow Nebula's recommendation exactly for cal/mag, which is 5 ml per gallon (like you) for the first 5 or 6 weeks and then cut back to half that. That seems to work well. (And I thoroughly wash my coco and pre-treat it with cal/mag.) I tried using less in an earlier grow, but rapidly ran into Ca deficiency (our water here is super soft).

Each five gallon dose lasts for a week. On my current grow, I did top off the reservoir once (rather than a complete weekly change-out) and thought I'd skip the Ca/Mg and just let it "coast" but I saw Mg deficiency within days. In my experience (again, with essentially mineral-free tapwater) cannabis really needs its cal/mag!

OK, fun time's over. Time to do my taxes.

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Does vinegar in coco = bugs?

Does vinegar in coco = bugs?

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