-
- Articles
Index : Plant Care
-
-
- 4. Comparing Garden and Landscape Fertilizers - Top
- There’s a dizzying array of fertilizers on the shelves of garden and home supply stores. Citrus foods - fruit tree fertilizers - tree and shrub foods - tomato and vegetable fertilizers - rose foods - flower foods - general purpose fertilizers and the list goes on and on. You’d think you need a special fertilizer for every sort of garden and landscape plant you have! Truth is, having just two or three fertilizers on hand is enough to cover all of your garden and landscape needs.
When it comes to landscapes your trees, shrubs, vine and ground covers can be feed with one product - a fertilizer high in nitrogen. All of these, even the ones that flower periodically, are considered foliage plants. Their leafy growth and overall health is dependant on nitrogen. If you look on the fertilizer label, nitrogen is the first number listed. In the case of landscape plants, this number should be the highest. In fact, I often use nitrogen alone, in the form of ammonium sulfate (21-0-0) to fertilize my landscape plants. It does the job to stimulate lush, leafy green growth. It’s also the fertilizer of choice for citrus trees!
Other fertilizers typically high in nitrogen are tree and shrub foods and lawn fertilizers. A caution about using lawn fertilizers to feed trees and shrubs - don’t use weed and feed products! They contain herbicides that can damage landscape plants.
Garden plants: including roses, annual and perennial flowers, fruiting vegetables such as tomatoes and peppers, and fruit trees (other than citrus) call for the use of a fertilizer containing both nitrogen and phosphorous. Flower and fruit formation is stimulated by the addition of phosphorous, the second number listed on the fertilizer label. Ammonium phosphate (16-20-0) is an excellent fertilizer for garden plants! Speciality flower, vegetable and fruit fertilizers (although more expensive) can also be used and are interchangeable. A flower fertilizer can be used for fruits and vegetables just as a vegetable fertilizer can be used for flowers and fruits. Keep in mind that unlike nitrogen, phosphorous has to be physically mixed into the soil, at the time of planting, to be effective!
Patio container plants have unique fertilization needs. Because their roots are restricted and their source of nutrients limited to rather sterile potting soil, they must receive a full compliment of nutrients on a regular basis. In addition to nitrogen and phosphorous, container plants also need potassium, magnesium and a full compliment of micro-nutrients such as iron, manganese, and zinc. Even if the potting soil you use has nutrients added, they’re rapidly used up and must be replaced.
Although I don’t recommend timed-release fertilizers for garden and landscape plants, I do for plants in pots. There are a number of timed-release fertilizer products to choose from such as Osmocote, Vigoro, and Dynamite brands. Choose a balanced fertilizer with similar levels of nitrogen, phosphorous and potassium. Balanced fertilizers are well suited to a wide variety of foliage, flowering and fruiting plants.
Finally, fertilization is not necessary for all plants. Our desert soils provide for the nutritional needs of native plants. Leguminous trees like mesquite, palo verde and acacia produce their own nitrogen in root nodules through a process called nitrogen fixation. However, non-native landscape plants do benefit greatly for regular fertilization, and it’s a must for garden and container grown plants!
Written by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,
520-626-5161.
- Updated: April 29, 2007
-
-
[e-Mail me
the Articles] - [Search
the Articles]
-
|
