How can i decrease my gardens PH?

[Chase S]

I recently got my garden tested for PH which i used last year and my neighbors garden which he is just starting this year, both came out to 7.5 Alkaline. We probably shouldnt have been surprised because the valley we live in actually long ago used to be a limestone quarry. Our gardens are about 10,000sq ft. Mines in a square and his is in a rectangle. He used to have cows and i still have a few llamas so we both have what some might some consider fresh, and "aged manure" although i would think "Aged" means in some drying area but we dont do that. Anyways we are working together on this and sharing equipment and work so we can both feed our families. We are looking for some way to decrease our PH to about 6.5 or 7 would be good, because thats where our plants like. I grew some food in mine last year but it could have done better which sounds consistent with being outside the ideal PH range. I have heard of Aluminum sulfur or something like that and we really dont want to use that if its a chemical thats not natural. Also we looked into composting and that was to confusing and time intensive especially on our scale which we mostly do by hand and tractor but fixing tractors takes time and money, so we try to limit our use of those. Anyways we're a month away from planting which i know is not ideal but is there anything we can do to start the process of changing the PH but still be able to plant? Any idea will do. Oh i also heard about Manure tea and pine needles. And he has 50gallon drums and i have a few hundred feet of pine trees. So thats a option to if we need to. Let me know what you guys think, thank you!