I wouldnt water it. I would buy a spray bottle or take one that you already have in the house, empty it out and clean it good and put some water in there and spray your plants instead of watering. I mean watering would work but still, and yes you could water . And those numbers (20-20-20) are just the nutritional value in the product. The first number would stand for N (Nitrogen), the second numbers would stand for P (Phosphorus) and the last numbers would stand for K (Potassium).