PH runoff to high~any suggestions?

Plants are about 6 weeks old. 4 GDP, 1 Zkittlez and 1 O.G. Kush. Grown in FFOF. No nutrients. My PH going in ranges from 5.8 to 6.1. On the runoff it jumps between 6.5 to 6.9. Any suggestions would be much appreciated.
Thanx in advance!

PH is right where you want it. Also should consider getting a TDS/PPM meter to measure runoff. Pictures of plant?

These pics are bout a week old. Cuz lights are off right now.IMG_1381

So the PH is ok than?

I do have a tds/ppm reader. My ppm’z range from 1133 to round 1900.

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Yes your PH is good. 6.5 is your target. The PPM over 1500 can cause leaf tip burn but I wouldn’t worry about it for now. Plants look good. Just keep an eye out for yellowing of the tips first. It just makes the plant ugly but is ok for bud production to have higher PPM. Just don’t want it to get too bad. When will you be flipping. Size of plants are about good for flip. Lights are a bit small for the number and size of plants, so you may consider upgrading. With the current lights you will probably get 3z from each of the plants but with the right light you would push your total yield pounds. Yield is limited by the true wattage and the efficiency of the lights. Burples aren’t very efficient, and generate a lot of heat. For a 5x5 you will need to invest $500-1000 for good LED lights but with ~800W you would yield ~2lbs.

I am flipping them tonight. The lights are 2 galxy hydro 300 and a 3500k rocket plasma.

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Those galaxy’s are only 100W each and very inefficient. Not familiar with the rocket. If you want suggestions for LED lights we can help. It is the best investment I made in my growing!

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always open to suggestions. Which do you like?

Your space is a 5x5? Are you willing to part together and DIY. You could fill a 5x5 with a strip light build for ~ $600. Build half now and half later. Really depends on how much you are willing to spend and when.

Yes it is a 5x5 7ft tall. I could swing 300 now and 300 in a couple weeks. What does this consist of?

I am going to refer you to a conversation with a build by @DoobieNoobie with help from @dbrn32

You would need ~30 Samsung strips @11.70 each, 2-3 Meanwell power supplies @57 each, framing and heatsink and other materials ~100

Alternatively you could go with QB 288V2 boards but this would be a bit more cost, but a lot less DIY.

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@dbrn32 did you see the tariff note on the arrow site for those strips? Has anyone ordered strips lately and did they have to pay a tariff upcharge?


Yes there’s a charge for it. It’s not much but give me a few minutes I’ll tell you exactly how much.


Last order I placed wasn’t very big, nor was tariff charge.

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Ok so my order in January was 26 strips and the tariff on them was 0.52 each and drivers were $0.50 on a little lpc-60-1050 driver and was $3.45 each on the hlg-185h-c1050b drivers. So grand total was $24 and change.

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Perfect. Nominal but not insignificant.

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With ffof one typically doesn’t see much deficiency until around month 3, (other than magnesium/calcium). If I don’t use anything but water I start noticing some yellowing of the leaves shortly after flipping to flower. So my typical grow now is about 2 months veg with just water. Then I begin adding low doses of grow nutes, give them 2 weeks of that. Then I put them in the flowering tent, give grow nutes another week, and switch to bloom nutes as soon as I see pistols forming.

Ffof contains a good amount of buffers, it’ll typically remain steady around pH 6.5-6.7 the first few months. Then as the peat breaks down it starts to get quirky. Keep an eye out for fluctuating pH at this point.
While runoff can give a good indication of what’s going on with your soil, it can also give some innacurate readings. It’s easy and quick so most people just test runoff, but if you want a better picture of where your soil truly lies then do a slurry test.

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I notice that pH drops quite a bit towards the end with the FFOF.


I think that is a little on the low side for FFOF ph going in unless you’re trying to fix a fluctuation.

I am interested in this situation. I’m in FFOF with runoff and slurry reading 7.2-7.4.
water going in is 7.1-7.3 (15ppm) - have tried vinegar ph’ing but readings hold steady in runoff.

have calibrated my pH meter (and have a new one on the way)
checked a bag of black gold (cheapo) as a sort of sanity check and pH in slurry was around 6.6-6.8

have pulled and cleaned the runtiest problem plant and placed it in smaller pot of black gold to see if growth resumes as half of my crop have stalled and turned really ugly.

been reading all day on the forum about high pH problems and have come across more than a few FFOF grows with this issue - ph’d water still comes out on the high end in runoff.

sorry to butt in and dont want to thread jack. just adding my situation. you arent alone.