UNDERSTANDING FERTILIZERS AND THEIR USES
Once the garden soil has been tilled with the organic material and sand incorporated consider fertilization.
Fertilizer increases plant growth only if it is a limiting factor. Plants grown in poorly drained soils, in excessive shade or in competition with tree roots do not respond to fertilizer.
Fertilizer is organic or inorganic. Organic fertilizers are manures, bone meal, cotton seed or other naturally occurring materials. Inorganic fertilizers contain manmade products.
The three numbers shown on fertilizer containers are the fertilizer analysis. They indicate the percent of nitrogen, phosphorus and potassium present in the fertilizer. These figures are always listed in the same order. So, a 100-pound sack of 10-20-10 fertilizer contains 10 pounds of nitrogen, 20 pounds of phosphorus and 10 pounds of potassium. That equals 40 pounds of nutrients. The rest of the fertilizer is simply carrier or filler, such as sand, perlite or rice hulls. A complete fertilizer is one with all three elements. A general recommendation for gardens and flower beds is 2-3 pounds of a slow-release, complete fertilizer such as 19-5-9 per 100 square (10' X 10') feet of planting area.
Just as people need nourishment, plants must have nutrients to grow and flourish. Plants need a balanced diet with all of the necessary nutrients readily available for their use. Plants will grow at optimum rates if nutrition is furnished on a "as needed" basis. If you incorporate the knowledge that plants need a continuous source of nutrition with the realization that the major pollutant of ground water is nitrates which can come from plant fertilizer applications, then the idea of using slow release fertilizers to feed plants small portions of the nutrition they need makes sense. Fertilizers which gradually feed plants rather than deluging them with excessive nitrogen are not only environmentally-sensible, but they also enable plants to grow at optimum rates. This is why slow release formulations are recommended for all plants, whether they are vegetables, flowers, trees, shrubs, groundcovers or lawns.
When fertilizing gardens, use a product containing slow-release fertilizer such as sulfur-coated or plastic-covered urea. When choosing a slow release fertilizer, it is important to note that the higher the percentage content of sulfur-coated or plastic-covered urea, the better.
The chance of groundwater contamination from excessive nitrates washing through the soil is lessened when greater amounts of slow release, sulfur-coated or plastic-coated urea are present. Of course, the more slow-release fertilizer present, the more expensive the product, but safeguarding the environment is certainly worth the cost difference!
Some of the better fertilizers will have at least 50 percent of the total nitrogen content of the bag as sulfur-coated or plastic-coated urea. This information can be determined by reading the Guaranteed Analysis found on each bag of fertilizer. Remember, the higher the percentage or units of sulfur-coated or plastic-coated urea, the more you and the environment benefit. To insure you have the best product, not only look for the "slow release" nomenclature on the bag, but you should also examine the Guaranteed Analysis which indicates what percent of nitrogen (the first number on the bag) is derived from sulfur-coated or plastic-coated urea.
Slow-release fertilizer in your gardens has the following advantages:
- Makes more nitrogen slowly available as a nutrient to the plant.
- Resists leaching or washing through the soil into the water supply.
- Deceases risk of fertilizer burn associated with heavy applications of conventional fertilizers.
- Releases independently of microbial and bacterial action.
- Offers controlled-release feeding for 10 weeks.
- Stimulates a more drought-tolerant plant.