I have read that you should use bottled water, or tap water if you let it sit out for a day. But then I read that bottled water lacks the nutrients that tap water has. Also how do you know when you have watered the plant enough? I dont want to make the mistake of over watering on my first plants w/ expensive seeds. Any help would be appreciated
buying expensive seeds for first grow = bad idea anyway, water it whenever you put your finger about an inch into the soil and you feel nothing but dryness. As for how much to water, use your common sense and mind, dont drown it.
water it enough so that your topsoil is at least damp. marijuana grows well in both well-drained and properly watered conditions. so even if you do give it a little too much, it wont be that big of a difference. if you see signs of overwatering, stop.
and as far as the what water to use concern, the best idea is to use your local tap water and let it sit out for a day. then its perfectly safe to use to water your plants. although its not much of a deal to water your plants with tap, what can happen is a "hard water" problem with your plants, basically meaning the water has too much of a certain element (probably chlorine or lead) and it damages the plant.