i personaly have a baby pool that i dump a bag of soil into,,add some pig shit,vermiculite,perlite,peat moss,,i usualy start with 70L bag ,and begin mixing aprox.20% of each to the soil only 10% of the pig shit,,,at same time as me mixing the wife has the mixed up nute water and is spraying it through the soil as keep mixing..i tell when its ready by how its looks and when squeezing it in my hand it kinda springs back out as apposed to crumbling ...and if your in the ground then shouldnt have any problems with watering...but if you need alot and its a decent distance away then i reccommend a rain catching barrel near your plants..