As a gardener it's important to know what is fertilizer made of and how it affects your plants. Fertilizers may be made from organic materials or from chemicals. Both can work equally well in the garden.
What is Fertilizer Made of and How Is It Made?
Fertilizers may be made from organic materials or inorganic materials. Some inorganic materials are manufactured, while others are obtained directly from the earth. Various minerals are considered inorganic fertilizers.
Organic fertilizers are made from plant material. Many consider them superior to inorganic fertilizers to condition the soil and improve the health of plants. Common organic fertilizers include:
- Compost: Compost is made from decomposed plants. Grass clippings, leaves raked from the lawn, apple peels, and any discard uncooked fruit or vegetable peels or cores can be added to a compost pile. Some people add shredded newspaper, tea bags and coffee grounds. Meat scraps should never be added to compost piles since they will smell bad and attract vermin to the pile. Compost piles are easy to make and most home gardeners can create a simple compost pile. As time goes by, the materials added to the compost pile begin to decompose thanks to the action of various microbes. The result is a rich, crumbly material often dubbed 'black gold' by gardeners.
- Peat moss: Gardeners often add peat moss to the soil to improve soil texture and add nutrients. Peat moss is harvested from peat bogs, where decomposing moss creates thick mats. It's then dried and sold by the bag or container for home use.
- Seaweed: Seaweed or kelp fertilizer utilizes harvested plants that grow in the ocean. These plants are nutrient-rich and decompose rapidly. You can buy seaweed fertilizers at many garden centers.
- Manures: Animal manure, such as cow and horse manure, can be added to the garden for natural organic fertilizers. Care must be taken to allow manures to age or they can burn the roots of plants.
Organic fertilizers create healthy soil by both adding nutrients and improving the texture. They also encourage beneficial microbes to proliferate, resulting in healthier root development and overall stronger plants.
Inorganic fertilizers are composed of ground up rocks, such as limestone and rock phosphate or manufactured chemical fertilizers. When they were invented in the 18th century, they were hailed as a boon for farmers and ushered in a golden age of agriculture. Chemical fertilizers may be grouped into two types: fertilizers suitable for home garden use and mass produced agricultural fertilizers. Fertilizers produced for home gardens are typically granular or pellet kinds of fertilizers to sprinkle around the roots of plants. Lawn fertilizers are placed in the hopper of a lawn spreader and gently spread on the grass. Most inorganic fertilizers for the home garden contain a balanced ratio of nitrogen, phosphorus and potash (potassium) expressed as a ratio of 10-10-10 or 20-20-20. Others may have slightly more phosphorus to encourage blooming, such as a 5-10-5 fertilizer. Read the package labels to select a fertilizer appropriate for your particular plants and garden.
Mass produced agricultural fertilizers are typically heavy in one or two macro nutrients, such as nitrogen and phosphorus, and are intended to spur plants on to immediate, heavy growth. Unfortunately, such fertilizers don't replenish the soil very well and when used for long periods of time can damage soil and create weak crops requiring heavier doses of fertilizer.
It's critical to read package labels and understand the proper fertilizer for your flowers, vegetables, trees, shrubs, houseplants or lawn. While a balanced fertilizer of 5-10-5 probably won't hurt most plants, some plants need high doses of one element over another.
The safest fertilizers to use are organic fertilizers. It's difficult to overdose plants on compost. In fact, most gardeners would say that the more compost is used, the better.
Whatever you do, don't go crazy with the fertilizer. Too much fertilizer is worse than none at all. While most plants can do just fine with minimal fertilizer, too much of the good stuff can burn roots and even kill plants.