What kind of nitrogen?

Asked February 25, 2016, 1:48 PM EST

We've diagnoses a couple of our tomato problems (wilt, blossom end rot) as being exacerbated by ammonium nitrate. I see this in a lot of commercial fertilizers, but want to know how to determine where various organic substances (compost, grass clippings, poultry and horse manure, etc) fall in ammonium nitrate - nitrate nitrogen content. Are we helping or hurting the situation using these organic amendments?

Mille Lacs County Minnesota organic fertilizer nitrogen ammonium nitrate

1 Response

This bulletin discusses the differences between organic and inorganic nitrogen sources and how they can best be used for a particular purpose.
http://extension.oregonstate.edu/gardening/node/955

This bulletin shows the relative amount of nutrients (including nitrogen) present in various organic fertilizers:
http://extension.oregonstate.edu/lane/sites/default/files/documents/lc437organicfertilizersvaluesrev.pdf

Although the information at this website pertains to lawns, it provides information about organic and manufactured fertilizers that may be useful as you determine how to best meet the nutrient needs of your tomatoes and other vegetable plants.
http://www.extension.umn.edu/garden/yard-garden/lawns/characteristics-of-natural-and-manufactured-fertilizers/