They last time I grew I used rain water and it did good. I was just wondering if I should continue to use rain water or tap or buy gallons of water.
I would think it would depend on the quality of water and how much salt is added to it if any when considering tap. RO would be the safest bet but rain water would be fine as well for the most part. Many municipalities list their water quality on their websites. Water in LA would be very much different than northern Cal.
RO water would be a bad idea unless you're johnny on the spot about providing all the nutrients and minerals for your plant. I've only ever used tap water, both inside and out, for all may plants. Whether they be 12' cannabis plants, culinary herbs, vegetables, grass, etc.
Depends on your tap water quality man. Im lucky and have soft water, EC 0.2 so I use that no problem. Buddy of mines has hard water 0.5 EC so he uses rain water. If you have hard water Id suggest using rain water, cheaper and more environmentally friendly than ro water. Think about water as a plate for your food, the lower the EC (Soft water) the more nutrients you can add to it. The higher the water (Hard water) you dont have as much room to play with