Fertilizing Plants & Trees

How Often Should You Fertilize and How Much Should You Apply? Here's a great article from the University of Georgia.

The frequency of fertilization depends on the type of plants being fertilized and the type of fertilizer used. If slow-release fertilizers are used, one application should be sufficient for the entire growing season. If general-purpose granular fertilizers are used, two or three applications may be needed, depending on the fertilizer's slow-release properties.

When general-purpose granular fertilizers such as 12-4-8 or 10-10-10 are used on newly-planted ground covers, annuals, herbaceous perennials and roses, light applications made at four- to six-week intervals are recommended.

During periods of limited rainfall or drought, reduce the amount of fertilizer applied and the frequency of application in non-irrigated areas. Fertilizers may injure the roots of ornamentals under drought stress.

Newly-planted ornamental trees and shrubs will benefit from light applications of fertilizer made during the first growing season after transplanting (Table 2). Uniformly broadcast the fertilizer along the perimeter of the planting hole. Avoid using weed-and-feed fertilizers in the vicinity of newly-planted ornamentals because injury from the herbicide may result.

Newly-planted 1-gallon size plants will respond to 1 level teaspoon of a 12 to 16 percent nitrogen fertilizer or a level tablespoon of an 8 to 10 percent nitrogen fertilizer applied in March, May and July. Small trees, fewer than 4 feet tall, should receive no more than 1 tablespoon of a 12 to 16 percent nitrogen fertilizer two to three times during the first growing season. Larger trees will benefit from 3 to 4 tablespoons of a 12 to 16 percent nitrogen fertilizer. Broadcast fertilizer along the perimeter of the planting hole. Remember that newly trans-planted ornamentals are under stress while they are trying to adapt to their new location and they can be easily injured by over-fertilization.

Table 2. Recommended fertilization rates for newly planted ornamental plants during the first growing season (use only one of the fertilizers listed at the rate recommended).
 

Application rate1/plant

Application frequency
Plant type/size

12-4-8

16-4-8

10-10-10

1-gallon shrubs

1 tsp.

1 tsp.

1 tbsp.

March, May, July
3-gallon shrubs

2 tsp.

2 tsp.

2 tbsp.

March, May, July
5-gallon shrubs

3 tsp.

3 tsp.

3 tbsp.

March, May, July
Trees under 4 feet

1 tbsp.

1 tbsp.

2 tbsp.

March, July
Trees 4 to 6 feet

3 tbsp.

3 tbsp.

5 tbsp.

March, July
Trees 6 to 8 feet

4 tbsp.

4 tbsp.

6 tbsp.

March, July
 

Application 100/sq. ft

Application frequency

12-4-8

16-4-8

10-10-10

Ground covers, annuals & herbaceous perennials

0.5 lb.

0.5 lb.

1 lb.

Each 4 to 6 weeks
1tsp. = level teaspoon; tbsp. = level tablespoon; lb. = pound. When using slow-release or soluble fertilizers, follow label recommendations for application rate.

The quantity of fertilizer applied on established ornamentals depends on the analysis of the fertilizer used, the area fertilized and the amount of growth desired. Nitrogen controls vegetative growth, so application rates are based on this primary nutrient. Table 3 lists suggested application rates for several general-purpose fertilizers.

DO NOT OVER-FERTILIZE OR FOLIAR DAMAGE MAY RESULT. To increase the application rate, increase the frequency of application, but do not exceed the amount recommended in Table 3 for each application. Optimum growth fertilization rates (three to five applications) are usually used on annuals, herbaceous perennials, roses and newly established ground covers to encourage their spread. Otherwise, low rates of fertilizer are recommended, particularly if you desire a lower maintenance landscape. As the application rate of fertilizer increases, so does the amount of new growth, which requires more water, more fertilizer and more pruning.


This product was added to our catalog on Wednesday 23 November, 2016.

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