What kind of Lime Tree do I need to buy to get the normal Limes that you normally buy in the store?
ph of 6.7 is only very slightly acidic. It's pretty close to neutral (7.0). Most plants LIKE slightly acidic soil. What are you trying to grow? That is your critical question. most vegetables, shrubs, trees and flowers like soil a bit acidic (around 6.0). A few like it alkaline (over 7.0). Adding lime will make your soil MORE alkaline. So unless you're planting something that really wants alkaline soil, I would NOT add lime. And if I were growing veggies that like it a little more acidic, I'd consider adding sulfur - to lower the ph. Most veggies are perfectly happy in 6.0 -6.5, or even 5.5-6.8. A few like it really acidic. Like blueberries - they prefer a freakish 4.5-5.5.
The pH dance is a tricky one. A lot depends on how acidic the soil is 'naturally' and what type if lime was used to lime the area. It's a matter of chemistry, the cation exchange capacity, and that's a mess to work with unless you're a science type. I would suggest, though, that you probably do not need to adjust the soil much, even into the untouched area. Unless there was a dumping ground or spill there originally, the pH should not be that much lower. I would only incorporate composted manure and vegetable compost; not humus (it will drop the pH). Blended well, it will maintain a neutral pH. 6.7 is pretty damn close to neutral...I'd be very happy with that.
Sounds like a fine garden. A little lime wouldn't hurt. But I wouldn't be shy of a little humus, and even doing nothing this year. No garden is the same from one end to the other.
