take the pot ur growin with seedling,take another pot same sizeand mix,weigh its dry weight,wen the pot ur growin weighs that amont water.i do seed starter trays,i put 50% perlite on bottom,5o% poting soil on top,i just wet each cell compleltly and plant,put into dark until sprout,then put under light.i check to see if there 1/2 dry 1/2 way down befoe i water again,complely weting cell.after a coulpeweeks goes to 4inch sq. pots with 2 inches of styrofoam in bottom of pot.i start out first two waterings,30-40 sprays from qt. sprayer bottle=about 1-1and 1/2 ounces,then on 3rd water on the tranplant flood,ever watering after that,40sprays,ever water until transplant.with 6-8 oz cups. i use 30-40 sprays. to start off,. and hold there for while,until water needs to be increase by 1/2- 1 tablespoon at a time,for me=10-15 sprays from a qt. sprayer bottle.