Hi there, My soil is around pH 7.2. I'm a bit stuck on what to do to lower it. I've had a look around but have failed to find any information on the subject (although I've now read several times that lime is used to raise pH), so now I'm asking you guys Thanks in advance!
fertilizers typically lower ph and 6.5-7.5 is a good range for soil grows with MJ or tomatoes. leave it as is
i would add literally two drops of vinegar to a pint of water to water it with... thats what my ph is at and doing that drops it right into the perfect range... literally check it urself.. such an inexpensive way of doing it and has no effects on the plant!
Dont be putting any substitutes for pH down in your medium, unless you like causing yourself unnecessary problems. Why don't you buy a bottle of pH down, thats what it's for and it is inexpensive (cheap).
The leaves seem a bit patchy and some are twisted, and one of the plants has a really mongy leaf. I have absolutely no clue what (if anything) might be wrong, but everything I've read says check your pH first, so that's what I'm doing. I'm going to check the soil pH before I do anything. I've had the water tested with a proper swanky laboratory pH tester (unfortunately I'll be in trouble if I try to use that for testing the soil so I'm waiting on some testing strips so I cn do it properly). The water is 7.7-7.9 (it's pretty hard water around here), so I'm guessing the soil will be around 7, meaning I'd need to lower it a little to hit 6.5-6.8. Since I didn't know how to do that, I thought I'd ask, in case I needed to buy anything special for it.
I'm more than happy to buy some if that's what I need, but I've read that stuff is just for hydro, not soil. Is that the case?
wrong way...lime will Raise the pH. Sulfur will lower it but it takes a while. Sphagnum Peatmoss is very acidic and can be mixed in to lower the pH. How did you test the soil pH?
Dolomite lime buffers ph, takes it either way. Keeps it constant. Buy the right soil, you can pretty much chuck your ph meter, no dont do that, but you wont be using it too often.
from wikipedia on dolomite lime: "dolomite and dolomitic limestone are added to soils and soilless potting mixes to lower their acidity ("sweeten" them)" lowering acidity means raise pH.
Oh I believe it, all our nutrients are acidic, cannabis is an acid-loving plant. Adding Dolomite lime will buffer your ph when you add it to your soil. It will keep it in a manageable(buffer) zone, because it will only let it go so far to the base side. Any soil with dolomite lime in it will be easier to work with when it comes to ph problems. If the soil is basey, it will actually bring it down if its real far to that side. So I guess its just how you read that quote from Wiki, it will raise the ph in soil that is already acidic, but this guy's soil isnt acidic. Epsom Salts would probably be the faster acting solution to his problem, but if he had dolomite lime mixed in from the beginning, he'd probably never have many ph problems at all, depending on how many chemicals he adds. Lime keeps the ph in the happy zone. http://www.a1b2c3.com/drugs/mjgrow9f.htm
You should also run your water through some kind of filter. A britta at least. RO is best. That'll help a bit. Also, adjusting the PH of your water will help regulate the soil PH gradually by leaching it in a sense. That's less invasive than re-potting with balanced soil, and a lot easier.
Thank you all for the thorough and knowledgeable replies. My plants actually seem to be a lot happier now. I have changed a few variables so it's hard to pin it down to one particular thing. They're receiving less water, but with nutrients in it, and I've dropped the peak temperatures a coupla degrees to about 26C. The twisting and patchy leaves haven't gone away, but they have stopped getting worse, and new growth isn't being affected. So for now at least, I'm happy. When the pH strips arrive I'll test the soil properly and maybe do something about it then, but for now they seem to be growing okay so I think the best thing to do is probably leave them alone! Thanks for all the excellent suggestions, though. I'll be sure to pick up some dolomite lime next time I'm potting up, as it sounds like a good no-risk pH 'safety net'.