pH Down. 2 lb Earth Juice pH DownLower pH with these all natural pH adjusting crystals. Earth Juice Natural pH Down can be used to adjust fertilizer and foliar spray solution for a much more effective use and faster absorption of nutrients by plants. Optimal pH range for fertilizer/nutrient solution for most plant and turf is 5.5-6.5. Mix solution thoroughly and adjust pH prior to application. U... — Ships from Portland, Oregon USA...more.