Ways to keep soil from going acid.

[FatSean]

Hi everyone. My name is fatsean and I have a pH problem. My potting soil likes to go acidic after a few weeks of flower. I use tthis stuff, it's got the best texture of the slim selection of locally available non-fertilized soils.

I'm currently working with powdered Lime product to address my pH issues. (Thanks Rusty!) I am experimenting with mixing quantities of it into my soil, and I am also trying to top-dress with it to address pH lockout issues noticed in flower. What happens is the fans start to go yellow and drop at about week 3 or 4 of 12/12 lighting and the plant's production slows over time.

So far I either put too much into the soil, and my poor plants look sick in a 7.0+pH medium, or I don't put enough into the soil and by the time I notice the lock-out, top dressing with the stuff never seems to get the soil back into happy pH zone. 2TBSP/gallon of soil seems too much, but a heaping TBSP/gallon of soil seems to little.

Should I just mail order soil? Is there a pre-made product that does NOT go acid in mid-late flower? It seems so wasteful to ship soil, but I'm open to new ideas. My FoxFarm nutes have alot of ammonium compounds for the Nitrogen, and the soil producer said those compounds make the soil go acid faster. Maybe a different fertilizer?

FatSean Reviewed by FatSean on 09-09-2009. Ways to keep soil from going acid. Hi everyone. My name is fatsean and I have a pH problem. My potting soil likes to go acidic after a few weeks of flower. I use tthis stuff, it's got the best texture of the slim selection of locally available non-fertilized soils. I'm currently working with powdered Lime product to address my pH issues. (Thanks Rusty!) I am experimenting with mixing quantities of it into my soil, and I am also trying to top-dress with it to address pH lockout issues noticed in flower. What happens is Rating: 5

[M.B.A.]

You should us my style of soil, great drainage, never had any ph/nute lockout issues. 65% Dirt or potting soil, 15%Perlite, 10%Builder'sSand (HomeDepot) and 10% Worm Castings. Hope it helps

[stinkyattic]

Your water is a likely culprit- if it is acidic to begin with, or quite soft, with lots of organic acids in it like tannins, you will find that your soil goes bad FAST. The real kicker if you happen to have organic acids is that you wouldn't necessarily notice them since many common ones in surface waters buffer in the high-6 range and go unnoticed until you see soil problems.
I'd deal with your issue like this:
-Maintain a frequent re-potting schedule so fresh roots always find fresh soil, being sure to do a good flush with pH adjusted water a couple days before repotting.
-Check the hardness of your water and its pH to try to get a sense for how it might be interacting with the soil.
-Plan to water with a nutrient solution that you KNOW to be of correct pH for your garden, and if your water is soft, run CalMag.

[FatSean]

Your water is a likely culprit- if it is acidic to begin with, or quite soft, with lots of organic acids in it like tannins, you will find that your soil goes bad FAST. The real kicker if you happen to have organic acids is that you wouldn't necessarily notice them since many common ones in surface waters buffer in the high-6 range and go unnoticed until you see soil problems.
I'd deal with your issue like this:
-Maintain a frequent re-potting schedule so fresh roots always find fresh soil, being sure to do a good flush with pH adjusted water a couple days before repotting.
-Check the hardness of your water and its pH to try to get a sense for how it might be interacting with the soil.
-Plan to water with a nutrient solution that you KNOW to be of correct pH for your garden, and if your water is soft, run CalMag.

I re-pot about three times from clone to flower, an I repot once more after 1-2 weeks in flower. Do you suggest more frequent repotting in flower?

- My water is from a well and is fairly hard. TDS 190-250 (varies by season) and the pH is usually 7.0 to 7.4 or 7.6 depending on season. I correct tap to pH 6.7 w/ GH's pH Down when feeding plain water. When I add my nutes to un-treated tap water, I need to use a bit of pH UP to get back to 6.7. White crust on fixtures, some rust in the washer, that kind of thing.

I have an R/O filter, I was previously using that water and adding CalMagPlus at 1tsp/gallon as a base. Using the tap seemed simpler...should I try the RO+CMP again?

Thanks!