What is the best way to amend garden soil?
Peat moss?
Manure, if you want just one ingredient.
I add kitchen compost, turn under the winter rye and vetch, and add a bag of organic humus from Walmart. The humus is cheap and has manure in it.
Depends on your soil type. What’s the pH?
Peat moss is anti-microbial. Not really useful in gardening other than storing bulbs and whatnot. Have you ever seen pics of the bog bodies?