If you're looking for a cheaper alternative to fancy soil but still want all that OHP fabulousness for your plants, check out this kit. It will take the guesswork out of soil mixing - just mix EVERYTHING inside the box with a 1-cubic-foot bag of standard potting soil from your local garden center, and you're good to go! This will make at least 15 gallons of incredible soil.

I recommend coco coir-based soils, as peat will eventually repel water and compact. Also, please be careful with your soil choice as we cannot be responsible for fungus gnats or other issues that can be present in mass-produced bagged soils from garden centers.