Long story short, I'm tired of paying 26 bucks a bag for Fox Farm. I don't know if I got hold of a bad batch or what, but last grow all my plants had some sort of deficiency that I could never nail down. Why pay so much for soil if the plants look like shit? I've decided that I'm going to make my own mix. I found some "Organic Compost" locally for $1.50 a bag and it's decent stuff. Made by a company called ASB Greenworld. I don't know what's in it exactly, but it looks really rich. I've got a couple seedlings in a mix of the compost and about 30 percent perlite and they're doing great so far. There are a few big sticks in it, but they're easy to screen out when you mix it up. So far I've got a mix of about 50% compost, 30% peat moss, and 20% perlite. I want to mix up a big ass batch of it (about 50 gallons worth) and let it cook. I use BMO nutes on my plants and they have a supplement called Super Plant Tonic. It's basically mycorrhizae and other stuff to keep the organic breakdown process going. I was planning on mixing up this stuff about 20ml to a gallon and moistening the mix down with two gallons or so to jump start the process. I have noticed the PH is off. My guess is that the compost is mostly leaves and what not. I've never mixed my own soil but I do know that lime will help. How much lime should I use per 50 gallons of soil mix? The runoff was in the mid sevens when I ran some distilled through it. Anything else I should add to this mix? Bone or blood meal? Kelp? Help me out here. What should I mix in and how much? Thanks in advance.
Since you don't know what's in the compost, there's no way to tell what the soil mix is missing. That said, I always add Bone Meal, Blood Meal & a seaweed fertilizer to all of my soil mixes. If the runoff pH is in the "mid sevens" when using pure, pH 7 water then your soil is alkaline, not acidic. Lime won't help alkaline soil. Always let water sit in the soil for at least an hour before collecting & testing runoff. Water that runs right out the bottom, the same time you water, hasn't had time to take on the pH of the soil.
dolamite lime will get the ph down,as well as up. it will maintain a nuetral ph,7. don't forget its possible that the soil will change over time and become acidic. why couldn't you get a soil test kit with npk and ph? it should give you a basic idea of what is in the soil to start,and possibly what you'll need to add.just a suggestion.
Thanks for the replies. I ended up going about 40% compost, 40% peat moss and 20% perlite. Like I said, the compost had some sticks in it, but I made a screen and it's prime now. I added a cup of dolomite per CF of soil as well. Obviously I can't speak for how it'll grow plants, but this soil looks amazing and cost about 1/3 of FoxFarm. Also, a soil test kit might not be a bad idea. I'm going to let it sit and get happy for a couple of weeks though.
I simply pot up my clones in Miracle Grow Organic potting soil ($4/bag) which has 2 months of fertilizer in it. The plants grow like crazy and I don't add nukes for 2 months and then only fish fertilizer (1 tsp. per gallon of water). I have never understood all the expensive additives and the "Fox Farm" is the best hoopLa, when growing pot. It's only a weed!
The pH of hydrated lime is 12.4@25C. This can be easily verified at Google, Wiki, etc. The only way it will cause an alkaline soil to become more acidic is if the soil's pH is already above 12.4. If you just got one pH tester to start, imho you should begin with wide spectrum pH drops. They're cheap, will test the pH of liquids, and can test soil pH via runoff. Always let water sit in the soil at least an hour before squeezing some out to test runoff. Even when buying more expensive pH meters, it's a good idea to have something like drops to regularly verify that the meter is accurate.
...your not getting your potential yields either. I'm just say'n. MG is garbage. If your growing in soil, try an organic grow (ie, AACT). Then you will understand. FFOF is an expensive soil, but it is full of organic goodness, it sells because it's good shit.
Thanks for the runoff testing tips Jellyman. I always just put the pot in a bucket to catch whatever runs out the bottom and then collect a sample from it. Thats what I did with the orginal compost/perlite mix and got high readings. Your way would clearly give better readings. FWIW, I use an aquarium tester with the drops and vial. Either way, it's probably a safe bet that the compost is alkaline anyway. I didn't know this until yesterday, but peat is acidic (somewhere around 3.0 IIRC) and the amount I added to the compost should offset the 7'ish reading of the compost. Just going by averages though, the peat may or may not have brought the mix to the 5's. If so, the dolomite should bring it back up if I've got all my facts straight. I'm going to let it cook for a good 2 to 3 weeks stirring it every few days and then give it a test. Goodbye Fox Farm. Nice knowing you.