Where do you get your buckwheat, Alfalfa and clover?? I'd like something smaller than 100 lb bags!!
There's a bunch of places you can get small quantities. I don't have my seed sources list with me at the moment but one that comes to mind is Peaceful Valley Farm Supply in California (
https://www.groworganic.com/). I order a lot of stuff from them. Then there's Hearne Seed, Hancock Seed, Burpee, Territorial Seed, etc.
Alfalfa is a perennial so you can cut and use as you need it, or there are a lot of cover crops you can grow over garden beds that are not being used. For winter medic is an excellent clover to grow. It's very drought tolerant and widely grown as a cover crop in arid parts of Africa and the Middle East. It'll self re-seed like buckwheat if you don't till it in before it flowers. Another really good perennial/biennial is yellow clover. The seeds are cheap and it is also extremely drought tolerant.