I believe that Mon wants to lower the pH of a hydroponic nutrient
solution not soil. The best thing to use is phosphoric acid. That is
what is in the pH down
products available from stores that sell hydroponic supplies. Try
www.wormsway.com. This should be safe for veggies. If you want a cheaper
solution you can try getting some 85% phosphoric acid from a chemical
supply house. Try daigger.com or vwrsci.com. If you get the 85% stuff,
dilute
it carefully 1:3 before using. Add phosphoric acid SLOWLY over the
course of several days as there is the potential for quick changes in pH
which will not make your plants happy.


Mon Chi Chi wrote:

How can I lower PH in my indoor garden. I am at around 7.0 and I want to get
to about 5.9 for my tomatoes. I have used aquarium product before but found
it to be expensive. I am not sure what product to use that will not harm my
plants as they are for human consumption...

mon
--
Stephen Sassman
Analytical Chemist
Purdue University, Department of Agronomy
Crop Soil and Environmental Sciences
915 W. State Street, Lilly Hall
West Lafayette, IN 47907-2054
Phone: (765) 471-9135