Take care of the soil year-round. Soil that drains well and is cleared of rocks, weeds and debris will support healthy crops and use fertilizer applications more efficiently. Growing cover crops is an excellent way to incorporate nitrogen back into the soil while also protecting it from erosion and compaction.
Organic sources of nitrogen are often found in animal manures. Manure that is at least partially composted is better than fresh because weed seeds will be less likely to germinate. Gardeners should follow EPA guidelines for incorporating manure into the soil for food crops to minimize health risks. Be aware of the risk of salt build-up due to salt content of manures. Do not add more than one-inch of manure per season unless a soil test has been done to evaluate salt levels.
Other organic sources of nitrogen include: blood meal, fish meal, bat guano and cottonseed meal. Keep in mind many organic fertilizers are slow-release and will become available over the season. Follow recommendations for proper application rates. Organic fertilizers often have lower nutrient concentrations and may require higher amounts to be applied. They can also be costly highlighting the importance of proper application rates and timing.