Article
Tree And Shrub Care: Fertilization
By Joey Reynolds
Landscape plants can benefit from occasional fertilization. There are some things to consider before you fertilize.
You should test your soil before you fertilize. If you add compost to your soil every year, you will not need to fertilize as often. There are several ways to test your soil. Most department stores sell soil testing kits and pH testers. The soil testing kit comes with instructions on how to use them; and usually have a liquid that turns a certain color if your soil is lacking a nutrient. The pH tester comes as a probe to stick in the soil, and has a meter that tells the soil pH level. Another way to test the soil is to ask for a kit at your local Extension Agency or a soil testing lab. They will have you gather soil from several locations around yoru site, mix the soil samples together, then they will test it for a fee. They will send you a comprehensive analysis of your soil.
The main nutrients in soil are nitrogen, phosphorus and potassium. Nitrogen is for protein production, proper growth of leaves, and for the critical functions performed by plants. Phosphorus is for strong roots. Potassium is for fruit and flower production. pH is the alkaline or acidity of your soil. Most plants prefer a pH of 6.5 to 7.0, but not all. If you notice a plant isn't looking healthy, it may be lacking one or more nutrients. Decide what is needed and apply the necessary fertilizer.
When you fertilize depends on each plant. Usually, the best time to fertilize is early Spring. Autumn fertilizing can cause new growth on the plant that will not be winter hardy, and this can damage the plant. There are several types of fertilizer. Some types are spikes, liquid and granular.
Spike fertilizers are inserted into the soil around the base of the plant. They can be an expensive way to fertilize as their nutrients go straight down, and only where the spike is placed. So you need alot of them close together around the base of the whole plant to cover the root zone.
Liquid fertlizers are sprayed around the base of the plant, and are usually safe to spray on the foliage. They soak into the soil around the plant.
Granular fertilizers are placed around the base of the plant, and then are either watered or rained into the soil. If there is a heavy rain though, some of the fertilizer can be washed away.
You can also use powdered fertilizer that you mix with water and apply as a liquid.
Other ways of applying fertilizers are by using a soil probe and making holes, starting about 2 foot from the base of the plant, out to the dripline, and add fertilizer directly into the holes. This gets the fertilizer closer to the roots and will help the plant absorb it quicker. Another way is to drill a hole in the trunk of the tree and insert a type of fertilizer spike. The wound will heal over the spike and the fertilizer will be released over time.
There are quick-release and slow-release fertilizers. A fertilizer with a combination of both is best.