For personal and environmental reasons, more people every day opt to forego eating meat in favor of a plant-based diet. The gardeners among them soon ask if their gardens can run without manure, fish meal and other animal inputs, and the answer is a resounding yes. In addition to using routine organic gardening practices like composting and mulching, which raise the organic matter content of the soil, vegan gardeners should emphasize two other techniques: cover cropping and making homemade plant-based fertilizers.
Solar-Powered Winter Cover Crops
Cover crops, especially nitrogen-fixing clovers, vetches and peas, use solar energy to manufacture nutrients and organic matter for your soil. The best are winter cover crops that grow when most veggies do not, and explode with new growth when days lengthen in early spring. To explore your options, check out Ben Vanheems’ great video on recharging your soil with winter cover crops.
In my garden, my formula for success with tomatoes and peppers is to plant them in holes dug into the stubble of fall-sown crimson clover, which is mowed down just as it reaches full bloom in late spring. It is truly miraculous how the plants prosper with no additional fertilizer, have no issues with blossom end rot, and produce generous, tasty crops.
I’ve also started using daikon radishes as a winter cover crop, mostly because the soil likes them so much. The plants grow big in fall and die in winter, leaving behind deep wedges of rotting organic matter. The dead radish foliage mulches the soil through winter, until I rake it off and compost it in the spring.
Homemade Vegan Fertilizers
Everything costs more these days, and none of us have money to waste, so please think carefully before paying exorbitant prices for vegan fertilizers. Of the few vegan fertilizers available, all are crazy overpriced for what they are, which are blends of soybean meal with rock phosphate, dried seaweed, and another seed meal or two. They are good fertilizers and people love them, but at $5 a pound, you could source seed meals and other ingredients at the swankiest health food shop in town and save money.
Better yet, see what you can find at farm supply stores, and get creative. In 2020 I wrote about using organic chicken feed and alfalfa pellets as plant-based fertilizers, but there are many other materials to consider. Don’t get hung up on finding soybean meal, the main ingredient in commercial vegan fertilizers. Soybean meal has an impressive NPK of 7-2-1, but when used straight up as a garden fertilizer it is far from perfect. In one experiment, soybean meal reduced germination and early growth of lettuce, turnips and other vegetables, and caused root burn when used around transplanted peppers.
This may not have happened if the soybean meal had been given a week or two to meld with the soil before seeds or crops were planted, which is the best way to work with all plant-based fertilizers. The idea is to feed the soil, allow time for digestion by microbes, and then let the soil feed your plants.
If going to a farm supply store is out of reach, you can still blend your own plant-based fertilizers using plant meals from the store. Soy flour, chickpea flour, and whole wheat bread flour are high in nitrogen, with corn meal not far behind. When mixed into the soil with compost and given a week or two to decompose, any of these flours can do double duty as a garden fertilizer.