Anyone know the dosage for soil drench for 3 gallon citrus? I'd like to do it and recycle the water that drains to avoid polluting the storm water and save cost.

I normally use about 12 oz of finished mix in a 3 gallon pot. Apply the mix when the plant would normally need watering. The goal is to saturate the medium without any of the liquid leaving the pot. I have found this getting this exactly right is not easily done, but 12 ozs has the the desired effect for for most potting materials. I use a mix consisting mostly of pine bark fines.