It kind of depends on the size of your garden too. If it's a small garden, you can use bottled water. The kind that you get from a machine or water store for around a quarter a gallon. You can also look on ICmag.

This is a thread for a cheap DIY Ro filter setup for small scale growers...
International Cannagraphic Magazine Forums - DIY Reverse Osmosis - For Scale Grower - Cheap, Portable, & Effective
lmdesade Reviewed by lmdesade on . THE PPM of my Faucet water is 760ppm!!! What do i do???Help I just received my tds meter and my faucet water is saying 760 ppm!!! What do i do??? I have a hydro grow in process right now and i dont know what i can do with such a high reading??? Someone please help!! Rating: 5