There are some major benefits to using organic fertilizers, namely that they work slowly as they need to be broken down by soil organisms for their nutrients to be released, and this takes time. However, because they work slower than inorganic or chemical fertilizers, nothing is wasted, as everything is consumed as it is released.
Soil containing organic fertilizers tend to be easier to work with as the organic material contributes to the structure of the soil, allowing more air to get to the roots of the plant which permits the soil to hold water longer. Due to the extra organic substances in the fertilizer, fungal and bacterial activity are also increased. Overall, organic garden fertilizers improve the soil, allowing your plants to flourish.
While you still need to be careful with organic fertilizers, they are less likely to burn the roots of your plants (especially delicate seedling roots) or create a toxic concentration of salts when over-applied. Below are some examples of organic fertilizers—some of which can even be found around the house.
Manure (Animal Dung)
Most manure used for your garden comes from cows, sheep, poultry, and horses. There are exceptions of course, such as chicken manure and rabbit manure (which tomatoes enjoy for their nitrogen boosting quality). Manure has a lot of organic matter, but it is lower in nutrients than other organic fertilizers.
Manures are best used as organic soil amendments and mulches. Soil amendments have a number of uses such as improving your soil’s drainage and density as well as adjusting the pH balance.
Be careful when using fresh manure as a fertilizer as it is known to burn plants.
Shellfish Fertilizer/Shell Meal
Shellfish fertilizer is made from the crushed bones or shells of crabs, shrimp, and other shellfish. It contains a great deal of calcium (it is made up of 12% of calcium) as well as phosphorus, nitrogen and a number of trace minerals. Another advantage of using shellfish fertilizer is that it contains chitin which boosts the growth of beneficial organisms that destroy harmful pest nematodes.
The caves where bat guano is found protect the substance from leaching, so the nutrients found in the guano are conserved. For this reason, it is high in soluble nitrogen, phosphorus, and trace elements. Bat guano can be used any time of the year as a top dressing, or try diluting it in a tea and using it as a foliar spray.
If you can get hold of it, South American seabird guano is the best. It is rich in nitrogen, phosphorus and a number of other nutrients.
Fish emulsion is partially decomposed, finely ground fish, so it can smell, but there are deodorized versions on the market. Use it sparingly as it is known to burn plant roots.
Eggshells are made up of 96% calcium carbonate crystal, bound together by proteins, so they can be used as a fertilizer to strengthen the cellular structure and the transport of nutrients in your plants. Eggshells decompose very quickly, so there is no need to sterilize them or grind them up.
Tomatoes and peppers will enjoy some egg shells mixed in with their fertilizer as they are easily affected by calcium deficiency.
Plants that crave an acidic environment, such as roses, hydrangeas, and berries will love you for dowsing them with a vinegar mixture once every three months. Simply mix a tablespoon of vinegar with a gallon of water. A low pH can be harmful to plants that thrive in a highly acidic environment. Just be sure to test your soil before you alter the pH levels.
Epsom salts (hydrated magnesium sulfate) contain both sulfur and magnesium, which plays an important role in the photosynthesis process. This assists plants with a number of functions, such as root growth, amino acid production and the formation of chlorophyll.
Onions, broccoli, and cabbages will all benefit from the use of Epsom salts as a fertilizer, which will, in turn, sweeten the produce. Peppers, tomatoes, and roses will blossom and grow stronger when fertilized with Epsom salts. Use Epsom salts in a solution to replace depleted levels of magnesium and sulfur in potting soil.
Epsom Salts, like other foliar applications or liquid fertilizers, have the added benefit that their nutrients are absorbed into the soil more quickly than other organic fertilizers.
Make sure that any ingredients you add to your organic fertilizers don’t contain other harmful chemicals, such as herbicides, as these will defeat the purpose. As most organic fertilizers are slow-release, the timing of when you use them is not as important as it is with inorganic or chemical fertilizers.
As with all the foods we eat, organic is best, so why not nourish your plants as you would nourish your body?