EC is a much more reliable standard where as ppm can vary by as much as 300-400 ppm based on many manurfacturers, countries, and other variables.

Get an EC meter and then research the appropriate EC for young seedlings.

good luck

peace
melodious fellow Reviewed by melodious fellow on . Bonsai Buds I bought one of those Aerogardens thinking to myself "Geez! This'll be a great way to grow myself some weed!" Well, after reading through the posts on Aerogarden growing, I realized that this might not work. I had no idea what my nutrient levels were, nor my Ph. I didn't know if the nute tablets that came with the set-up were good enough, nor was I sure whether or not this was a good investment for my money. Anyways, I did my homework, and I drove into the big city to buy myself a reliable TDS Rating: 5