Hey all just wanted some feedback on this soil mix I made for my first large outdoor grow (150gal)! Any advice appreciated ! 5 part peat moss ~95gal 2 part perlite ~38gal 1 part compost ~19gal 10 cups gypsum 3 cups bat guano 7 cups kelp meal 10 cups crustacean meal 13 cups azamite Should I add any more nutes? Worm castings? More guano? I’m also thinking I overdid the azomite - should I be worried? I’ve never made a soil before.. Also, is this mix ready to transplant a large plant directly into, or do I need to ‘cook’ it first? thanks all for the help!!
Chicken Manure is my best amendment. I'll usually add a 1 pound coffee can worth per Cubic foot every other plant in the same soil. A better, more sustainable choice then bat guano and double or triple your amounts. About half the Kelp amount in Alfalfa meal in my blend. Your heavy on Gypsum and Azomite but nothing to be done now. Outside, what is your water supply like ? My hose water is 8.5 PH so I run an acidic soil to help keeping in check the PH push all that water eventually causes. Sulfur Dust @ 1 yablesppon per CF when I amend. BNW
Congrats on building your own soil, it's always the best. The only two things I would suggest is adding another part of compost - that adds all the microbiology to your soil mix and gets things cycling. In addition I'd suggest a source(s) of nitrogen (fish meal, neem, feather meal, alfalfa, soybean etc). *Edit - Your base mix is roughly 20 CuFt - it's usually recommended to add 1/2 - 1 C calcitic lime to peat based mix per CuFt...for PH buffering. I live in SoCal and I have fairly hard water....so I do 1 Tbsp a gallon...just shy of 1/2C per CuFt. The gypsum amount is about the same, so I think you're fine....but your mix definitely has a healthy amount of calcium between the crustacean, gypsum, and lime if you add it. As for "cooking" you should always let it sit at least a week if possible.
Thanks so much for the response!! I was thinking I’d add more nutes as needed by top dressing ; but I am definitely open to adding more at this point too- would you still recommend the full 1lb/cubic ft of chicken manure? As far as my outside water supply goes, it comes out at about 8.5ph as well. Is the sulfur dust your way of keeping the soil acidic to compensate for that? ‘Thank you again !!
Thanks so much! I can definitely add another part compost to the mix. For the nitrogen, my bat guano is 7,3,1 - would that work? If so - how much should I add? Would the chicken manure recommended by BrassNwood work for that if not? ‘As far as buffering goes you’re thinking I should be okay with the amount of gypsum I have, or would you still recommend more lime? Lastly, I was wondering if you know if cut grass will work/be smart for mulching the whole thing? Thanks so much for the wisdom!
Ahhh, I assumed you were using P rich bat guano. I think you'll be good N wise. The Chicken manure will add N and more calcium too. It can also count as part of the compost addition. The gypsum isn't going to help buffer your soil mix, it is calcium sulfate, it needs to be a calcitic (calcium carbonate) lime (found in oyster shell flour, calcitic lime/ag lime/garden lime, and dolomite lime), these react with the acidity to neutralize it .
Yes on the Sulfur. I skip adding any Lime as it just made it worse. Most City water supplies are kept at 8 to 8.5 to protect old iron pipes still in the system. Most plants can tolerate it so it's a compromise. I'm also in Southern California. Hot and dry all year round. I water. And water, And water more. Eventually it started showing in the plants. Once I started adding sulfur at amend time thing got better and continue to. I may even try some Aluminum Sulfate for faster action. You can always make a tea from Manure and hit them later if they seem Nitrogen deficient. It is fairly potent (Hot) and start small until you can judge how it's working. A word on Compost. Very little of what is sold and marked as "Compost" actually is. Most of it doesn't come close being just ground up trees. (actually worse it's a nitrogen sink) Coast of Maine, Lobster Compost is one of the real deals. EWC is always good. (Earth Worm Castings) Adding a few live worms couldn't hurt either. BNW
Right on, thanks again for the input !! I’m thinking I’ll grab some sulfur dust as well as some neem meal maybe for pest control and a little extra nutes. I’ll be happy to top dress later rather than make the soil too hot right now. Would you still recommend I go for the 1tbsp/cf of sulfur mixed into the soil before planting or wait to top dress it later? thanks!!
Add it now. Sulfur dust is the slower method to lower soil PH. Takes microbes to convert it into tiny droplets of Sulfuric acid. 3 to 6 months if I recall to change soil PH 1/2 a point. Aluminum Sulfate for action in days and weeks rather then months if memory serves me right. Both are commonly used to acidify soil for use with Hydrangeas to get them to flower blue. BNW