I do not know if there is an organic fertilizer specifically labeled for onions. Furthermore, this innocent question is giving me a headache (not your fault! LOL) because I can't decide how to answer it. I have 3 or 4 different answers dancing around in my head and cannot decide which one is the "best" answer, and I don't think I can weave them into one coherent answer either. So, here's my attempt at answering this question.

1. THE POLITICALLY-CORRECT ALL-ORGANIC ANSWER: As a mostly organic gardener, I know that fertilizers, in general, are overrated. To me, if I enrich the soil with a variety of organic amendments, it will have a balanced blend of the various nutrients, including trace elements. So, when you see me tell someone that "I feed the soil and the soil feeds the plants", that is what I mean. In that instance, I am also saying, indirectly, that any other fertilizer is not necessary. But, we live in the real world.....

Is my soil, after nine years of organic enrichment, the kind of soil that will feed the plants? Yes. BUT, if someone is in their first, second or third year as an organic gardener, it is unlikely that they have added the perfect blend of organic materials to give the soil every single thing it needs. There are just so many things you can add to the soil and there is no perfect formula because we all start out with different dirt to begin with.

So, for someone brand new or fairly new to organics, I'd say an organic fertilizer might be necessary for a couple of years (or more) until the soil is well-improved. That leads us to....

2. THE OLD-FASHIONED ANSWER: Improving the soil. If it is your first year to grow onions, add several inches of organic material to the soil. This could include compost, composted manure, greensand, lava sand, soft rock phosphate, cottonseed meal (maybe), alfalfa meal, bone meal, blood meal, chopped up or shredded leaves, fish meal, kelp meal, etc. It is hard to get soil TOO IMPROVED for onions (because they love rich soil) unless you go way overboard on amendments high in nitrogen. All these various ingredients WILL feed the soil, and the soil will feed the onion plants. Still, what about the trace minerals? And, that leads us to ....

3. ACTUAL PACKAGED ORGANIC FERTILIZERS. The first thing you will notice is that the N-P-K numbers on organic fertilizers are significantly lower than those on chemically-based synthetic fertilizers There are many different brands of organic fertilizers, but they tend to be sort of regional, so what you find in one area may differ from what you find in another area. There are a few nationally-distributed lines. One of those is the Gardens Alive! Root Crops Alive! fertilizer for onions (available online). It is supposed to be great, but you don't know what is in it because they don't tell you that in their catalog or on their website. It also is a little expensive. I think it is a granular product.

One of my favorite brands of organic fertilizers is the entire Espoma line. They are available at many nurseries and garden centers in the Dallas-Fort Worth metro area, and I occasionally see them up here in southern OK or north Texas (the Gainesville Home Depot carries one or two of them). For onions, you could use Espoma Plant-Tone (5-3-3). (They also have a Tomato Tone that I used for tomatoes.) What's in it? A blend of the following: Dehydrated manure, feather meal, crab meal, cocoa meal, corn gluten meal, dried blood, sunflower meal, kelp meal, alfalfa meal, greensand, rock phosphate, sulfate of otash, sulphate of potash margnesium and humus. WONDERFUL stuff for the garden. It contains a complete and balanced blend of all the necessary nurients: nitrogen, phosphate, potash, calcium, sulfur, magnesium, manganese, boron, molybedum, chlorine, cobalt, sodium, copper, iron and zinc.
It is granular. You can work into the soil before planting and also can topdress with it later in the growing season.

Another one that is widely available is Monterey Fish & Poop Fertilizer (9-6-2). It is derived from fish meal, blood meal, fish emulsion, and sea bird guano. You can apply it as a foliar spray or a soil drench. It may be that none of these (or a similar product) is available locally for you, which leads us to....

4. THE FINAL ANSWER: You also can make your own organic fertilizer and it is not that hard. Just blend together one organic amendment that will give you nitrogen, one that will give you potassium, and one that will give you potash. Or, just use one of the following: Bloodmeal (12-1-1) (kind of high in nitrogen for an organic fert., so don't use too much of it), Cottonseed* meal (7-2-2), Fish Meal (12-1-1). Or, feed with liquid fish or liquid seaweed.

There, I told you the answer wasn't simple! LOL I could have just listed the names of three or four good organic all-purpose fertilizers, but think I would have been missing out on a good "teachable moment". I wanted you to know not only the "what" but the "how" and "why".

And, for anyone who wants to go the synthetic route, the easy answer is to buy a fertilizer that is a 1-2-1 ratio, like 10-20-10 or whatever.

I plant my onions in a bed enriched every year with a couple of inches of compost (the decayed remains of the previous year's mulch) and throw in other amendments from time to time. It is more art than science, which is true of organic gardening in general.

Dawn

Thank you for taking the time to answer this thouroughly. I actually have pretty good dirt and had really good compost to add to the ground before tilling it up.

I was hoping it was something easy, like add alfalfa or soybeal meal, or even a fish head or two, : ), I hear they are high in nitrogen. . .

Again, thank you for taking your time and helping out here.

You're welcome.

Oh, and about those fish heads.....go ahead if you don't mind the smell and if your nearest neighbors are far, far away. Otherwise, the smell (even if they are buried in the soil) is probably a deal breaker.

And, if you happen to add blood meal or dried blood, (which are a slaughterhouse by-product that are high in nitrogen), the odds are that you will soon have vultures looking for the dead animals that go with that blood. The first time it happened to me, I couldn't figure out why vultures were circling over the garden (and over me!) for the whole day. Apparently they can smell that blood!

Dawn