A quick question about soil PH

Hi guys,

Watered with: 7.2
Run off: 6.2

is my soil ph therefore around 5.8 and too low or is it 6.2 like the run off is?

My girls arent looking too happy, taco leaves some yellowing/brown spots on lower leaves. I think I have a lockout because my soil ph is too low. Just a quick question about my soil ph, i watered yesterday with 7.2 until i had a large run off to try and raise my soils ph but im getting 6.2-6.3 from the run off. Would this put my soil around 5.8-5.9 as in its too low and should I just keep watering with 7.1-7.2 to try and correct the problem?

Thanks in advance.

jayzigger said:

Hi guys,

Watered with: 7.2
Run off: 6.2

is my soil ph therefore around 5.8 and too low or is it 6.2 like the run off is?

My girls arent looking too happy, taco leaves some yellowing/brown spots on lower leaves. I think I have a lockout because my soil ph is too low. Just a quick question about my soil ph, i watered yesterday with 7.2 until i had a large run off to try and raise my soils ph but im getting 6.2-6.3 from the run off. Would this put my soil around 5.8-5.9 as in its too low and should I just keep watering with 7.1-7.2 to try and correct the problem?

Thanks in advance.

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Issues are rarely related to soil ph. As long as you monitored what goes in and kept it steady, that's what matters, runoff in most cases is not worth paying much attention to at all. The only way to get a proper reading on your medium's ph, is to take out a clump of it from the root zone and mix it with plain ph'd water and test that after allowing it to sit for some time (depending on what the medium is). Runoff will not tell you anything much in a reliable manner, either with ph or ppm's. When you say you're growing in soil..what exactly is it? is it clay based? What have you been feeding and in what dosages? How old is your plant? What lights do you use? What kind of water are you using? Also..a picture speaks a thousand words

Soil buffers well and swings around quiet a bit. Not sure why your watering at such a high PH for....

Your issues sound more like heat stress and nutrient issues.

If you ever like, you can check with your probe. Just mix a sample with distilled water. Just plain distilled water. The ratio will be on google or wiki.
You can do ppm's that way too. I like to take a sample from the top, and bottom of the pot. Then compare the two.
Like the boys say. Runoff isnt reliable in soil. You get an average at best.

Okay here’s the deets guys:


Week 5 since seed now I had a bit of a slow start

Strain: 2 x Bubba Kush

Soil: canna pro + 40% perlite + 2% Bokashi soil amendment

Nutrs: GH trio feeding for the last 2.5 weeks every 2nd time I water and spraying with seasol foliar feed when I’m not giving GH trio (water once pots dry out every 2-3 days till slight run off)

Water: all feed and water ph’d between 6.3-6.8

Light: 600 watt vipar spectra led (276 actual draw) was @ 24-28 inches for majority but moved up to 31 inches a couple days ago because of top/new growth tacoing

Temps: 20c at night and up to 27 max during the day usually around 24-25c. RH usually between 55-75.

Plant #1 analysis (pics 1,2,3,4): I thought I had a ph problem and lock out because I raised lights and new growth kept tacoing, also water went from 7.2 >>5.9 run off at first and got run off up to 6.2 by flushing (extra droopy today because of flushing yesterday.) Today I notice yellowing on 2 of the lower leaves and a couple of brown spots (seen in pics 1,2,4), seems like mag lockout??also a burnt tip on new growth (pic 3).

Edit: I just let some of topsoil (can’t get soil from bottom) from plant #1 sit in 7.1ph water for 30 minutes and drained — water came back at 6.55.

Plant #2(pic 5): doesn’t look as bad as plant 1 no lower leaves with brown spots//yellowing. When I flushed it yesterday run off was coming in a bit higher than plant #1, started at about 6.1 and got to 6.3 by the end but still tacoing leaves on new growth. Bottom right of photo 5 you can see bad growth//discolouration on lower leaves of plant 1.

Any ideas or suggestions appreciated. Thanks for the help in advance.

I don't think Canna pro is soil.

if I'm right you have to use Hydro PH, not soil.

Sorry canna terra pro potting mix, it’s a peat moss blend of things apparently

jayzigger said:

Sorry canna terra pro potting mix, it’s a peat moss blend of things apparently

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Adjust your pH to a 6.1 - 6.3 range.

Hey mate how exactly can I tell my ph range because apparently run off is not a useful indicator and when I left the soil to soak in ph7.1 water it ended up becoming 6.5. Thanks.

jayzigger said:

Hey mate how exactly can I tell my ph range because apparently run off is not a useful indicator and when I left the soil to soak in ph7.1 water it ended up becoming 6.5. Thanks.

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pH meter is needed and perhaps some pH down or up depending on the situation. The more you can do to get it right going in the run off will come out fine if you do that

It looks to me like you're feeding too much. GH dose every other time you water and foliar in between means you're feeding every time you water. From what I've seen of those who foliar feed, they don't have good success with it. If your soil already has fert in it and you're adding more, it might be too much. To foliar on top of that makes things worse. I would stop feeding so much as it's possible you're poisoning the plant with too much fertilizer. You can't feed and feed in soil as the nutrients will stay in the soil for a while. You have to be careful how much you give and how often you give it.

jayzigger said:

Sorry canna terra pro potting mix, it’s a peat moss blend of things apparently

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exactly..the most common mistake I see people making when starting out..they automatically think dirt is soil..when in reality, many of these store bought mixes are actually peat moss based and should be treated with a ph closer to 6 as oppose to near 6.5 like in soil. Get a ph meter as it's a must if starting out and not doing strictly organics. Without knowing what went in, its hard to guesstimate what the issue may be. Especially in peat moss or coco..ph going in is important to know!

Update: I flushed yesterday to get ph run off up to 6.5, last flush I gave a small dose of calmag. They both look a bit better, just wondering if the taco leaves will ever go away or will the growth stay like that forever? Cheers, pics attached.

It looks like the pots are half wet and half dry.

Yeah not sure bro must be the camera I flushed yesterday with about 3x the soil volume of ph’d water and a tad of calmag at the end so they were evenly watered.

jayzigger said:

Yeah not sure bro must be the camera I flushed yesterday with about 3x the soil volume of ph’d water and a tad of calmag at the end so they were evenly watered.

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A 3x flush could cause this alone. Don’t know why you added calmag but after that much water I might use like 15-25% base grow nute back in.

jayzigger said:

Update: I flushed yesterday to get ph run off up to 6.5, last flush I gave a small dose of calmag. They both look a bit better, just wondering if the taco leaves will ever go away or will the growth stay like that forever? Cheers, pics attached.

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Sweet! I must have been posting at the same time.

They are coming right out. Old damaged growth may be ignored and new growth is where to look for improved health. Although I have seen plants really green back up.

Don’t forget cal mag is not a complete nutrient and the instant green effect will go away fast without a good NPK too.

I prefer a complete nutrient with micro nutrients included for convenience. Mrs. MMG will mix up a few gallons to help that way.

Ohhh gotcha thanks mmg. I’ll wait till they dry out again and then give them a feed to get some nutes back in the soil. I gave cal mag because I had some yellow leaves/brown spotting developing on lower leaves that were in direct light and moving up the plant so I just guessed they might have some lockout due to low ph. Will post back in a few days with how next feed goes. Cheers

jayzigger said:

Ohhh gotcha thanks mmg. I’ll wait till they dry out again and then give them a feed to get some nutes back in the soil. I gave cal mag because I had some yellow leaves/brown spotting developing on lower leaves that were in direct light and moving up the plant so I just guessed they might have some lockout due to low ph. Will post back in a few days with how next feed goes. Cheers

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Good to learn about nutrients. Down low means mobile nutrient deficiency up high or newer growth immobile nutrients.

Lockouts in potting soil are from salt buildup usually. Ph is stabilized by the calcium input in the soil like lime or oyster shell.

Water within a standard range doesn’t change the soil ph. And the soil ph fluctuates on it own with the plants processes.

jayzigger said:

Okay here’s the deets guys:


Week 5 since seed now I had a bit of a slow start

Strain: 2 x Bubba Kush

Soil: canna pro + 40% perlite + 2% Bokashi soil amendment

Nutrs: GH trio feeding for the last 2.5 weeks every 2nd time I water and spraying with seasol foliar feed when I’m not giving GH trio (water once pots dry out every 2-3 days till slight run off)

Water: all feed and water ph’d between 6.3-6.8

Light: 600 watt vipar spectra led (276 actual draw) was @ 24-28 inches for majority but moved up to 31 inches a couple days ago because of top/new growth tacoing

Temps: 20c at night and up to 27 max during the day usually around 24-25c. RH usually between 55-75.

Plant #1 analysis (pics 1,2,3,4): I thought I had a ph problem and lock out because I raised lights and new growth kept tacoing, also water went from 7.2 >>5.9 run off at first and got run off up to 6.2 by flushing (extra droopy today because of flushing yesterday.) Today I notice yellowing on 2 of the lower leaves and a couple of brown spots (seen in pics 1,2,4), seems like mag lockout??also a burnt tip on new growth (pic 3).

Edit: I just let some of topsoil (can’t get soil from bottom) from plant #1 sit in 7.1ph water for 30 minutes and drained — water came back at 6.55.

Plant #2(pic 5): doesn’t look as bad as plant 1 no lower leaves with brown spots//yellowing. When I flushed it yesterday run off was coming in a bit higher than plant #1, started at about 6.1 and got to 6.3 by the end but still tacoing leaves on new growth. Bottom right of photo 5 you can see bad growth//discolouration on lower leaves of plant 1.

Any ideas or suggestions appreciated. Thanks for the help in advance.

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Looking at your soil and the way your plants are drooping and looking I would say entirely too much water stick your finger in up to the first knuckle and see how wet it is should be pretty dry