What is the best (cheap) way to gradually establish GH, KH, and pH?

[JAGalletta]

I have very soft water, with a good pH (right around 6.4-6.6), and my plants are not doing very well in it. My KH and GH are both under 4 degrees. What is the best/cheapest way of establishing a better environment for a large variety of plants in this tank?

[shellieca]

IMO a small amount of crushed coral in a mesh bag is the best way to raise your PH. Start with a small amount, check you Ph 24 hrs later, add or remove a little crushed coral as needed.

[JAGalletta]

Thanks!!