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Search Results for: Organic fertilizers | Search the catalog for: Organic fertilizers

Plant Answer Line Question

Keywords: Organic fertilizers, Soil amendments

I was wondering if you could provide me with a more or less exhaustive list of organic fertilizers and soil amendments, their nutrient profile, and what they are good for, etc.


When you say 'organic' fertilizer and soil amendments, do you mean those items which are allowed under current organic regulations? I ask because there is considerable difference of opinion over what is meant by the word 'organic' in this context. Sewage sludge which contains heavy metals could be said to be organically derived, but might not pass muster in an organic garden, for example.

If you mean products which are on the Organic Materials Review Institute list of permitted soil amendments, here is a link to their lists.

If you need a truly exhaustive list, I recommend looking at some of the books available in the Miller Library on this subject. Rodale's Illustrated Encyclopedia of Gardening and Landscaping Techniques edited by Barbara Ellis (Rodale, 1990) has a very easy-to-use (but probably not exhaustive) guide to soil amendments and fertilizers. Below are are some other titles:

Soils : the right way to use fertilizers, composts, soil conditioners, soil testing/problem soils 1986

Let nature do the growing : the fertilizer-free vegetable garden / by Gajin Tokuno c1986

Fertilizers and soil amendments / Roy H. Follett, Larry S. Murphy, Roy L. Donahue

Fertility without fertilizers : a basic approach to organic gardening / Lawrence D. Hills

Feeding plants the organic way / Jim Hay

Growing green: animal-free organic techniques / Jenny Hall and Iain Tollhurst

The following links may be helpful to you:

Colorado State University Extension - Organic Fertilizers

National Sustainable Agriculture Information Service - Sources of Organic Fertilizers and Amendments

University of California Santa Cruz Agroecology Program - Building Fertile Soil

Washington State University Extension - Organic Fertilizers

Oregon State University - Improving Garden Soils with Organic Matter

Utah State University Extension

Date 2017-05-11
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Plant Answer Line Question

Keywords: Vaccinium, Organic fertilizers, Fertilizers

Is ammonium sulfate considered an organic fertilizer? I'd like to use some on my blueberries, but suspect it is not organic.


According to Fertilizers and Soil Amendments by Roy Hunter Follett (and others), ammonium sulfate is one of the oldest chemical fertilizers, and is "a frequent by-product of the steel industry, particularly the coking of coal." That doesn't sound like it meets organic guidelines. It is also tricky to use because it can cause phosphorus and aluminum to build up in the soil. The Organic Materials Review Institute lists it as a prohibited (for certified organic growers) synthetic crop fertilizer and soil amendment. You might do better using a slow-release certified organic fertilizer labeled for acid-loving plants. Cornell University Extension's publication, Production Guide for Organic Blueberries" mentions fish, soy, and alfalfa meal as organic-acceptable amendments.

Date 2017-07-18
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Garden Tip

Keywords: Organic fertilizers, Fertilizers

Gardeners with a wood burning stove or fire place often wonder whether they can use the ash as a source of potassium. The answer is yes if only wood (and no glossy paper) was burned. Where and how much? That depends. Wood ash raises soil pH, so if you have acid soil use it on the vegetable garden where a neutral pH is preferred, but avoid shrubs that like acid soil, such as Rhododendrons and Camellias. Recommended amounts vary, from a cupful around rose bushes to 20 pounds per 100 square feet for slightly acidic soil. Always work it into the soil. Read more about wood ashes from Oregon State Extension

Date: 2007-03-26
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May 23 2018 14:32:42