Fertilizer is a type of compound applied to gardens and landscapes to encourage proper plant growth and development by providing essential vitamins and minerals. Fertilizers make it possible to grow plants even in nutritionally deficient soil, as well as enclosed spaces such as garden pots. Gardeners have several options when choosing fertilizers to help create the lush garden they've always wanted.
Synthetic or Natural Fertilizers
Synthetic fertilizers are typically made of inorganic or organic materials. They have precise nutrient levels which are instantly available to the plants to stimulate healthy growth. Synthetic fertilizers release their nutrients rapidly and typically need more applications per year than organic fertilizers. Organic fertilizers, such as animal manure, are often longer-lasting than synthetic compounds. They depend on decomposition and microbe activity to release nutrients, thus making these fertilizers potentially smelly and varying in efficacy depending on the outdoor temperatures.
Complete fertilizers are some of the most common types available at nurseries and garden stores. These products are formulated with the three primary nutrients that plants need to grow---nitrogen, phosphorous and potassium---and display the nutritional ratio on the bag label. For example, the fertilizer may read "10-10-10" or "10-20-10," indicating the ratio of nitrogen, phosphorous and potassium, respectively.
Controlled-released fertilizers are popular among gardeners growing houseplants or who want to combine the slow-acting nature of organic fertilizers with the precise nutrients of synthetic formulas. The fertilizers are typically made up of pellets or granules coated in a special plastic that releases fertilizer nutrients whenever the plant is watered. This helps to ensure plants receive small doses of nitrogen to boost plant growth while minimizing the risks of chemical burns, a potential problem when using too much synthetic fertilizer.
Although many fertilizers come in powder, granule or pellet form, some gardeners prefer to use liquid fertilizers. These typically contain the same nutrient levels as dry fertilizers but may be easier to apply because they can simply be poured onto the plant. Like dry fertilizers, liquid fertilizers may be organic or synthetic.
Fertilizers With Herbicides
Some fertilizers are designed to both boost plant growth while limiting invasive weed species. This type of fertilizer is commonly used to help lawn growth by providing grass with the nutrients it needs while keeping down weeds that may compete with the grass for light, water, nutrients and space.