Organic fertilizers high in nitrogen include manure, cotton seed meal, guano, and the by-products of slaughter houses – bone meal, tankage, and dried blood.
The best organic fertilizer sources of phosphoric acid are bone meal and rock phosphates.
Potash is found in the ash of hardwood trees and seaweed.
The food value of organic fertilizers varies so that they cannot be labeled as precisely as the chemical ones. Organic fertilizer mixtures are now being packaged, however, with the approximate percentage of each nutrient on the bag.
Types Of Organic Fertilizers For Gardens
We enumerate the best types of organic matter to use for soil fertility or soil amendment. Unlike synthetic fertilizers or non-organic fertilizers, they contain single ingredients with enough nutrients to serve as plant food. Also, they did not undergo numerous process to achieve a certain level of quality.
These fertilizers break down easily and offer more soil conditioning features than actual nutrients. They improve the soil structure by adding drainage and moisture retention. Examples of plant-based fertilizers include:
- Alfalfa meal
- Compost tea
- Cottonseed meal
- Green manure cover crops
- Kelp meal
- Kelp seaweed
- Legume cover crops
- Soybean meal
These fertilizers serve as a rich source of nitrogen for the soil. It’s great for vegetables and leafy plants. Example of animal based fertilizers:
- Blood meal
- Bone meal
- Fish emulsion
- Fresh manure
- Manure tea
- Urea (urine)
- Fish and seaweed fertilizers – as it includes animal matter, it can’t be considered as a veganic fertilizer. You can buy these from organic storehouses such as Neptune Harvest.
Nitrogen, phosphorus and potassium, also known as NPK or organic NPK fertilizer function as a great source of macro-nutrients for plants. They belong to the mineral-based fertilizers category along with:
- Epsom salt (magnesium sulfate)
- Organic dry fertilizer
- Humic acid
- Nitrogen phosphorus combination
- Potassium sulfate (potash)
- Feather meal (nitrogen)
- K mag
- Phosphorus fertilizer (fish bone meal)
The Best Organic Fertilizers
You can use the following organic matter to fertilize your garden plants, vegetables, and crops. Different organic fertilizers require different application and care methods.
The oldest of all organic fertilizers – and still the best – is animal manure. In addition to its nitrogen and other food content, it is high in humus and contains bacteria which-improve the soil.
With the advent of the motor age, manure has become hard to obtain and rather expensive for the city gardener. If obtained direct from the farm, it has the further disadvantage of often containing seeds which sprout in the flower bed.
Air dried manure in which seeds have been killed is available commercially. Sheep manure is the most commonly sold. Rabbit manure is the highest in nitrogen.
Cow manure – 0.6% Nitrogen, 0.4% Phosphorus, 0.5% Potassium
Chicken manure – 1.1% Nitrogen, 0.8% Phosphorus, 0.5% Potassium
Sheep manure – 0.7% Nitrogen, 0.3 % Phosphorus, 0.9 Potassium
Pig manure – 0.8% Nitrogen, 0.7% Phosphorus, 0.5% Potassium
Rabbit manure – 2.4% Nitrogen, 1.4% Phosphorus, 0.6% Potassium[source]
Guano is the droppings, feathers, and decayed bodies of bats and marine birds. It is very high in nitrogen, but is not always available.
Bone meal is high in both nitrogen and phosphoric acid and is very slow acting. As long as it is not placed in direct contact with the roots, it can hardly be overused. It is especially recommended for bulbs and for plants like peonies which should not be disturbed for many years.
Ground up alfalfa that compost in the soil faster than other nutrients.
Tankage, Dried Blood Meal, And Others
Tankage and dried blood meal are so high in nitrogen that they must be used with care and are best used in compost.
Manure and bone meal have a slight alkali effect on the soil. Cotton seed meal has an acid reaction and is valuable for use around acid-loving plants such as azaleas or on soil that is inclined to be alkaline.
Lime And Aluminum Sulfate
Lime and aluminum sulfate are found on the fertilizer shelf at stores, but properly speaking, these are not organic fertilizers. They do have a definite purpose in the garden, however.
The sole purpose of aluminum sulfate is to acidify the soil. It may be used on soils that are too alkaline, around acid-loving plants, and around hydrangeas to make the flowers blue instead of pink.
Lime has the opposite effect. It counteracts acidity. It has the further effect of improving heavy clay soils by making fine particles of earth stick together. Many gardeners use small amounts of lime on the compost pile to sweeten such acid reactors as sawdust and pine needles. It hastens decomposition, but at the same time releases valuable nitrogen to the air so must be used sparingly.
Make Your Own Organic Fertilizer
In addition to organic fertilizers that may be purchased, there are others that you must make yourself. A compost pile should be in a shady spot in every garden. Compost is what you make it.
You may add leaves, grass clippings, clean garbage – potato peels, carrot tops, weeds – sawdust, corncobs, and any other such material available. Sprinkle with manure or tankage and add chemicals if you like. Besides the food value, compost adds invaluable humus to the soil.
Humus is a decaying organic matter. The texture of the soil and its water retaining qualities depend upon the humus. A humus soil has good drainage, is well aerated, and yet retains moisture. Humus is also obtained from decaying mulches.
Organic And Inorganic Fertilizers
Products with labels “natural” and “organic” went through a minimal process with nutrients keeping their natural forms instead of undergoing refinement and extraction. Natural organic fertilizers received this kind of treatment and they get manufactured in a factory or in a farm.
Inorganic matter, also known as synthetic fertilizers or chemical fertilizers have been refined and modified to bind nutrients in exact amount into one form. The process goes far from organic fertilizer production. Chemical fertilizers under this group may be made out of petroleum products, rocks, or even organic matter. Some of chemical nutrients included may occur naturally but they went under refinement where they got stripped of some substances.
Gardeners prefer organic material over inorganic for lawn care due to the latter’s many disadvantages. First, compared to organic products, the chemical fertilizers only nourish the plants but has nothing to do with the soil. As these chemical fertilizers don’t replace the nutrients lost from the soil, it may gradually affect future plants and this can lead to a long-term damage to the soil.
Over fertilization poses as another problem. As chemicals with the exact amount of nutrition are present, a small error in application of inorganic matter may cause a devastating effect. Long term use of chemical fertilizers may also upset the soil resulting to increased pests and boosted greenhouse gases.
Proper Application Of Organic Fertilizers
It is important that you apply organic lawn fertilizers at the right time. In general, organic fertilizers should be applied as new plant growth begins. That is usually in spring or fall.
Hot summer suns and cold winter frosts are alike hard on tender plant growth. You should, therefore, fertilize early in the spring after frosts are past so that the growth will harden before summer. If you apply organic fertilizers in the fall, do it after the burning heat of summer is past but in time for new shoots to harden before winter.
BULBS should be fertilized with a slow acting or slow-release fertilizers when they are set out. They may also be fertilized – but not with a high nitrogen fertilizer – after they have bloomed and when the foliage is ripening and next season’s flowers forming.
TREES may be fertilized by punching holes at the edge of the leaf line and tamping in fertilizer.
DO NOT FERTILIZE any plant immediately after transplanting. Wait a few weeks until it is established.
DO NOT OVER FERTILIZE any plant. Plants that received too much synthetic fertilizers will produce more leaves and lesser flowers. Even if you use an organic fertilizer the effect will remain the same.
Always WATER fertilizers into the soil. Plants can absorb only solutions. Dry fertilizer is not only unusable but is likely to burn the roots.
Several SMALL FEEDINGS a few weeks apart are better than one large feeding.
By considering soil, plants, and results, you can select the organic fertilizers that will make your garden thrive. Use them wisely at the proper time, and you will be delighted with the results of your organic gardening.