The best organic fertilizer is one that feeds the soil and plant with a rich array of needed nutrients, as opposed to organic fertilizers containing basically Nitrogen, Phosphorus or Potassium.
There are experts who consider each of the following to be the best organic fertilizer.
You can purchase compost, such as mushroom compost (chicken dropping compost that has been used to grow mushrooms) and cow manure, at your local lawn and garden store. Better yet, start your own compost pile.
Most manures need to sit for a year or more to give good bacteria a chance to break them down. Once they go through this composting process, they make an excellent fertilizer, especially rich in Nitrogen. Unlike other manures, rabbit and chicken manure do not need to be aged, but can be used immediately.
This is a rich organic fertilizer collected from caves where bats make their homes. It is made up of bat dropping mixed with decomposed bat bodies.
The castings of earthworms are God’s gift to gardeners. Earthworms live by ingesting soil, digesting it, then excreting it. What comes out is a super rich fertilizer. By providing the healthy soil and organic matter that worms thrive in, your soil will be enriched with worm castings throughout the year.
You can make your own vermicast if you like. Start with a large container like a 55 gallon drum, alternate between layers of dirt and kitchen scraps, and put in some earthworms to get things going. Keep the mixture moist but not wet for best results. You may also purchase worm castings from your local lawn and garden center, or here.
Another option is to greatly increase the amount of earthworms in your soil. This is accomplished by restoring true balance to the soil.
Though each of the above fertilizers may quality for the “Best Organic Fertilizer” title, they may be lacking in trace minerals. However, it is easy enough to add in the needed minerals. The best source I have found is concentrated sea minerals.
Fish emulsion is a good source for Nitrogen, Phosphorus, Potassium, Calcium, Carbon, plus all of the trace minerals.
It is a great fertilizer whose main drawback is its smell. When you get it on your hands or clothing, you’ll wish you hadn't. How can something that smells so bad grow such good tasting produce? But it does!
Kelp is a form of seaweed. Because it comes from the ocean, it contains all of the micronutrients found there. Kelp is especially useful for supplementing other fertilizers.
Though Kelp and Fish Emulsion do contain all the trace minerals, they don't have near as great a concentration of trace minerals as low sodium concentrated sea minerals. Kelp and Fish seem to work so much better when you add in a bit of sea minerals to them. Or you may use a concentrated sea mineral product by itself.
I had a friend in California with an apple orchard who tried the fish/sea mineral combination, and was amazed at how quickly it brought his struggling young apple trees back to life. The sea minerals are also a great source of food for beneficial bacteria in the soil, helping to strengthen the soil food web.
Not only does it contain a healthy amount of sea minerals, it prompts the plant to massive amounts of sugars through the roots into the soil (called carbon sequestration), which in turn is used by bacteria to highly structure the soil.
Organic Fertilizer Pages
After extensive research, the items in this right column are ones that my family and I have found useful, and I trust
that they may be helpful to you as well.
Concentrated sea minerals,
blended with herbs,
and olive oils.