Organic and Inorganic Fertilizers and Materials for the Home Gardener

Home gardeners today have many choices when considering how to improve the soil and add nutrients. With the renewed interest in gardening practices that emphasize conservation and sustainability of our natural resources, many people have an interest in using organics to build the soil and supply needed nutrients.
Applying fertilizers and adding soil amendments can impact the pH of the soil. Speed and duration of the reaction depend somewhat on soil type, organic matter, temperature, available moisture, or fertilizer solubility in water. Soil pH is a measure of the acidity or alkalinity of the soil.
Managing soil pH is important for gardeners because plants grow best in certain pH ranges. Plants may also exhibit nutrient deficiency or toxicity symptoms as a result of soil pH. Correct soil pH only when it is substantially higher or lower than required by the plants you are growing. Select plants that will grow in the natural pH of your soil rather than changing the pH, as long as the existing pH range provides good nutrient availability. Refer to Extension Publication 2571 Soil pH for Landscape Plants for more information on pH and the optimum pH ranges for common landscape plants.
This publication lists selected organic and inorganic fertilizers and amendments, their speed of reaction (nutrient availability), and effect on pH so homeowners and gardeners can develop strategies for better management of plant growth and soil productivity. This information is intended as a reference only and should not take the place of a soil test.
Improper use of fertilizers can contribute to water quality problems, so always follow recommendations of a soil test to make sure you are applying only what is needed for healthy plant growth.
Organic Material |
Nitrogen (N) % |
Phosphorus (P205) % |
Potassium (K20) % |
Relative Speed of Reaction |
pH Effect |
---|---|---|---|---|---|
Alfalfa Meal |
4 |
1 |
1 |
Slow |
Acid |
Bone Meal (steamed) |
1 to 4 |
15 |
0 |
Slow |
Acid |
Cocoa shell meal |
2.5 |
1 |
2.5 |
Slow |
Neutral |
Compost |
1.5 to 3.5 |
0.5 to 1.0 |
1.0 to 2.0 |
Slow |
Neutral |
Cottonseed Meal |
7 |
3 |
2 |
Slow |
Acid |
Crushed Granite |
0 |
0 |
5 |
Very Slow |
Neutral |
Dried Blood (Blood Meal) |
13 |
1 to 2 |
1 |
Rapid |
Acid |
Feather Meal |
12 |
0 |
0 |
Slow |
Acid |
Fish Meal |
10 to 11 |
6 |
0 to 2 |
Slow |
Acid |
Hoof and Horn Meal |
12 to 14 |
2 |
0 |
Medium |
Neutral |
Kelp Meal (Seaweed) |
1 |
0 to 0.5 |
4 to13 |
Slow |
Neutral |
Linseed Meal |
5 |
1 |
1 |
Slow |
Acid |
Manure, dairy |
0.6to2.1 |
0.7 to 1.1 |
2.4 to 3.6 |
** |
** |
Manure, duck |
0.6 |
1.4 |
0.5 |
** |
** |
Manure, feedlot |
1.0 to 2.5 |
0.9 to 1.6 |
2.4 to 3.6 |
** |
** |
Manure, horse |
1.7 to 3.0 |
0 .7 to l.2 |
1.2 to 2.2 |
** |
** |
Manure, poultry |
2.0 to 4.5 |
4.5 to 6.0 |
2.1 to 2.4 |
** |
** |
Manure, rabbit |
2.4 |
1.4 |
0.6 |
** |
** |
Manure, sheep |
3.0 to 4.0 |
1.2 to 1.6 |
3.0 to4.0 |
** |
** |
Manure, swine |
3.0 to 4.0 |
0.4 to 0.6 |
0.5 to 1.0 |
** |
** |
Peanut meal |
7 |
1.5 |
1.2 |
Slow |
Neutral |
Pelleted Chicken Manure |
2 to 5 |
1.5 to 3.0 |
1.5 to 3.0 |
Slow/Medium |
Neutral |
Processed Liquid Fish Residue |
4 |
2 |
2 |
Medium |
Acid |
Seabird/Bat Guano |
9 to 12 |
3 to 8 |
1 to 2 |
Medium |
Acid |
Soybean Meal |
6 |
0 |
0 |
Slow |
Neutral |
Wood Ashes |
0 |
2 |
4 to l 0 |
Fast |
Basic |
*Organic fertilizer is defined as a material containing carbon and one or more elements other than hydrogen and oxygen that are essential for plant growth. These organic materials also supply various secondary {sulfur, magnesium, calcium} and/or trace elements {boron, manganese, zinc, copper, iron, and molybdenum).
**The speed of reaction and effect on pH depend on how the manure is stored, the moisture content, and how it is handled before application.
Primary (%) |
Secondary (%) |
Trace (%) |
|||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Inorganic |
Nitrogen |
Phosphorus |
Potassium |
Sulfur |
Magnesium |
Calcium |
Boron |
Zinc |
Iron |
Speed of Reaction** |
pH Effect |
Material |
(N) |
(P205) |
(K20) |
(S) |
(Mg) |
(Ca) |
(B) |
(Zn) |
(Fe) |
- |
- |
Ammonium Sulfate |
20 |
0 |
0 |
24 |
0 |
0 |
0 |
0 |
0 |
Rapid |
Very Acid |
Borax |
0 |
0 |
0 |
0 |
0 |
0 |
11 |
0 |
0 |
- |
- |
Calcium Nitrate |
15 |
0 |
0 |
0 |
0 |
21 |
0 |
0 |
0 |
Rapid |
Basic |
Chelated Iron |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
12-May |
- |
- |
Di-ammonium Phosphate |
18 |
46 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Rapid |
Acid |
Epsom Salts (Magnesium Sulfate) |
0 |
0 |
0 |
13 |
10 |
0 |
0 |
0 |
0 |
Rapid |
Neutral |
Iron Sulfate |
0 |
0 |
0 |
7 |
0 |
0 |
0 |
0 |
12 |
- |
- |
Magnesium Ammonium Phosphate |
7 |
40 |
6 |
0 |
15 |
0 |
0 |
0 |
0 |
Slow |
Neutral |
Mono-ammonium Phosphate |
11 |
48 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Rapid |
Acid |
Potassium Chloride |
0 |
0 |
60 |
0 |
0 |
0 |
0 |
0 |
0 |
Rapid |
Neutral |
Potassium Magnesium Sulfate |
0 |
0 |
22 |
23 |
11 |
0 |
0 |
0 |
0 |
Very slow |
Basic |
Potassium Nitrate |
13 |
0 |
44 |
0 |
0 |
0 |
0 |
0 |
0 |
Rapid |
Neutral |
Potassium Sulfate |
0 |
0 |
50 |
16 |
0 |
0 |
0 |
0 |
0 |
Rapid |
Neutral |
Sodium Nitrate |
15 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Rapid |
Basic |
Superphosphate |
0 |
20 |
0 |
11 |
0 |
21 |
0 |
0 |
0 |
Medium |
Neutral |
Triple Superphosphate |
0 |
46 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Medium |
Neutral |
Urea |
46 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Rapid |
SI. Acid |
Urea Formaldehyde |
38 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Slow |
SI. Acid |
Zinc Sulfate |
0 |
0 |
0 |
16 |
0 |
0 |
0 |
35 |
0 |
- |
- |
*The nutrient content may vary from what is listed, depending on the manufacturer or purity of the product or other materials blended with the product.
**Soil type, organic matter, moisture, temperature, and water solubility of fertilizer used affect the reaction speed.
Rock Material |
Nitrogen (N) % |
Phosphorus (P205) % |
Potassium (K20) % |
Relative Speed of Reaction* |
pH Effect |
---|---|---|---|---|---|
Granite Meal/Dust |
0 |
0 |
3 to 5 |
Very Slow |
Neutral |
Greensand |
0 |
1 |
6 |
Very Slow |
Neutral |
Ground Limestone |
0 |
0 |
0 |
Slow |
Basic |
Gypsum (Calcium Sulfate) |
0 |
0 |
0 |
Medium |
Neutral |
Hydrated Lime |
0 |
0 |
0 |
Rapid |
Basic |
Rock Phosphate |
0 |
3 to 8 |
0 |
Rapid |
Acid |
Soft Rock Phosphate |
0 |
3 to 8 |
0 |
Rapid |
Basic |
Sulfur, Elemental |
0 |
0 |
0 |
Slow |
Acid |
*Soil type, organic matter, moisture, temperature, and water solubility of fertilizer used affect the reaction speed.
Other MSU Extension Resources
Suppliers of Organic Fertilizers, Rock Minerals, Composts, and Pelletized Poultry Litter in the Deep South by Steve Diver, NCAT Agriculture Specialist National Center for Appropriate Technology - Arkansas office
Test soil to find its pH value.
Gardening vegetables: organic gardening.
Organic crops geared more toward commercial organic crop producers.
The authors acknowledge the contributions of Extension Information Sheet 372 Soil pH and Fertilizers revised by Geoff Denny, PhD, Assistant Extension Professor, Plant and Soil Sciences, and Keith Crouse, PhD, former Associate Extension Professor.
Publication 2572 (POD-03-19)
Reviewed by Geoff Denny, PhD, Assistant Extension Professor, Plant and Soil Sciences. Originally written by Keith Crouse, PhD, former Associate Extension Professor, Plant and Soil Sciences, and Judy Pennington, PhD, Warren County Master Gardener.
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