Water?

[stinkyattic]

Well you want a P.H of about 7.0 isn't it?
Yes, that's a great PH level.... for your plants to die. You want 5.2 to 5.4. Some people say a little higher, but I spent a lot of time with various resources to come up with this number. Also since PH usually rises, it allows a little room for it to go up and not kill your plants.

.

This is true of hydro.
If you are growing in soil, you are going to want 6.3-6.8.
And in my soil experience, the pH drops over time.