Organic/natural fertilizers, on the other hand, don’t feed the plants directly but rather …. Well-aged manure on its own makes a great fertilizer for garden plants. Compost is the break down and decay of organic matter such as wood, leaves, plants, and vegetables. When ready to put into your garden and soil, compost should be a black, crumbly and fluffy (not wet and stinky), dirt like substance. Compost helps feeds the soil and acts as a holding sponge for your fertilizer. Here are 8 of our favorite DIY fertilizers for a variety of needs. Grass clippings. If you have an organic lawn, make sure to collect your grass clippings to use on your gardens. Weeds. Kitchen Scraps. Manure. Tree Leaves. Coffee Grounds. Eggshells. Banana Peels. Grass clippings also make an excellent nitrogen-rich fertilizer all by themselves. To make grass “tea” for your garden, fill a five-gallon bucket about two-thirds of the way with fresh clippings. Top off with water to within an inch or two from the lip.