Complete Organic Fertilizer

Steve Solomon is a knowledgeable gardener.  He has written several garden books, and started the Territorial Seed Company in 1979 when he was 37 years old. Seven years later, he sold the business but he continues to garden and grow a large portion of the food he eats. He has been growing most of his family’s food for over 35 years.

Many years ago, he formulated a recipe for a wonderful organic fertilizer.  The recipe used to be in the Territorial Seed Catalog before they began mixing and selling their own fertilizer.  It is good for all plants, and will make your plants thrive.  One should apply 4L- 6L of this fertilizer per 10m².

I’ve used this recipe myself for over 10 years now in Tasmania.

Complete Organic Fertilizer (COF) Recipe

Mix uniformly, in parts by volume:

Oil Seed Meal 3 6 9 12 15 18
Agricultural Lime  0.5  1  1.5 2 2.5 3
Gypsum  0.5  1  1.5 2 2.5 3
Rock Phosphate  1  2 3  4  5  6
Kelp 0.5 1 1.5 2 2.5 3
Potassium Sulphate 0.33  0.66 1 1.33 1.66 2
Zinc Sulphate 1.5 3  4.5 6 7.5  9
Manganese Sulphate  1.5 3 4.5 6 7.5 9
Copper Sulphate 0.5 1 1.5 2 2.5 3
Boron 1 2 3 4 5 6

Complete Organic Fertilizer Mix

Lime is an important part of the recipe. It is added not just to correct the pH of the soil but to supply Calcium which is essential for plant growth. Seedmeal which supplies the nitrogen factor has not nearly enough calcium or sulphur so supplying this element in lime brings in a nice balance. Agricultural lime is calcium carbonate and gypsum (also know as clay breaker) is calcium sulphate. I have quite clayey loam at Hampshire in Tasmania so I use equal amounts of Ag Lime and Gypsum. My soil, over the past 10 years, has become easily workable and the depth of garden bed has become deeper as the gypsum works it way down.

If you use 1 dose of COF each year spread at the rate of 6L for each 10m² over a thin layer of compost, which calculates to ½ tonne per acre, it is a rather small amount overall but will provide your veges with all the nutrition your plants need. The compost is important as it binds to the COF and keeps it at a level where your plants can access it. It also builds the humas level to hold moisture. Side dressing can be done every 4 weeks for heavy feeders like Brassicas, Tomatoes, Capsicums and Pumpkins. (No more than 4-6L extra per growing season)

Kelpmeal is wonderful stuff. This magic element from the sea provides a wide range of micronutrients and growth regulators acting like plant vitamins. Amazingly this helps plants increase their resistance to cold, frost and other stresses.  It can seem quite expensive bought from a hardware store but from Ironclad Goodness the middle man is cut out and 20kg will last many years.


Steve Solomon’s Latest Book

In Steve Solomon’s latest book The Intelligent Gardener: Growing Nutrient Dense Food he has updated his COF recipe to include many more ingredients and options.

  Ironclad Goodness in Hampshire, Tasmania manufactures complete organic fertilizer. Doing this commercially has advantages over the home gardener; we can include ingredients only obtainable by the ton in bulk, so we can build a complex mixture that releases some nutrients rapidly and others gradually, over a longer period. 

Click here to order Complete Organic Fertilizer.

In this latest book, he has also transformed from an expert “organic” gardener to an expert “nutrient dense” gardener.    The concept of nutrient dense food is pretty simple. Plants contain nutrients derived from the soil, so if the soil is low in nutrients so are your vegetables. The gardener works over time to balance the soil with the proper mix of minerals. The result will be an environment that encourages the soil life forms (worms, bacteria, etc.) to create soil that will grow healthier plants that are also more resistant to pests.

Below is the COF recipe included in Steve’s new book:

To make enough complete organic fertilizer to generously cover 10m², mix:

3L  oil seed meal such as soybean meal, cottonseed meal or canola seed meal or 1½L feather meal or fish meal (smelly)


  • 1L soft or colloidal rock phosphate (the best choice by far) or bone meal
  • 1L kelp meal  (And/or apply liquid kelp every 2 weeks as a foliar throughout the season.)

Add lime: choose one of these two options:

  • If you garden where the land originally grew a bush, add these two:
  • ½L agricultural limestone, 100# (fine grind) and
  • ½L agricultural gypsum;

or if you garden where the land originally grew prairie grass or is a desert add:

  • 1L agricultural gypsum

If you live in Australia, add 1/3 cup potassium sulfate.

The following last four items are optional:

  • 1 teaspoon laundry borax or Boron
  • 1 ½ teaspoons zinc sulfate
  • 1½ teaspoons manganese sulfate
  • ½ teaspoon copper sulfate

Mix all ingredients very thoroughly before spreading.


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