Fertilizing Tree and Small Fruits in the Home Garden

Commercial fertilizers, composted manures, and other fertilizers are applied to supplement a soil's natural fertility. The rate of material to apply varies according to past fertilizer use, crop grown, soil type, and other factors. 

General Recommendations  |  Strawberries  |  Raspberries  |  Currants & Gooseberries  |  Grapes  |  Blueberries  |  Fruit Trees  |  More Information

General Fertilizer Recommendations

A soil test will provide information to determine recommended fertilizer rates.  The tables below provide general recommendations for fertilizer rates of small fruits and fruit trees.

 *The amount of nutrients to apply does not equal the amount of fertilizer to apply.  To determine fertilizer amounts, consult this article: How to Calculate Fertilizer Rates for Lawn and Garden

 **Phosphorous is tested in two different ways depending on soil pH. Select the appropriate rate based on the test used.

Fertilizer Recommendations by Crop

Between soil tests, the following fertilizer recommendations can be used for established trees and small fruits in the home garden.

Strawberries

June-bearing Strawberries

Established plantings of June-bearing strawberries should not be fertilized in spring.  Spring fertilization stimulates foliar growth, increases disease problems, and produces softer fruit. Lush, vegetative growth may make picking difficult. Also, soft fruit are more likely to be attacked by fruit rots. As a result, spring fertilization may actually reduce the fruit yield. June-bearing strawberries should be fertilized during the renovation process immediately after the last harvest of the season. Apply approximately 5 pounds of a 10-10-10 or similar analysis fertilizer (such as 12-12-12) per 100 feet of row.

Everbearing and Day-neutral Strawberries 

Apply 5 pounds of a 10-10-10 fertilizer per 100 square feet to everbearing and day-neutral strawberries in early spring and again in early August. 

Raspberries

Established raspberries should be fertilized in spring before new growth begins. Apply 4 to 5 pounds of a 10-10-10 or similar analysis fertilizer for each 100 feet of row. Uniformly broadcast the fertilizer in a 2-foot band. If the raspberries are mulched with sawdust or wood chips, apply 5 to 6 pounds of 10-10-10 per 100 feet of row. Do not fertilize raspberries in late spring or summer. Late spring or summer fertilization encourages succulent, late season growth which is susceptible to winter damage.    Manure may be used as an alternative to commercial fertilizers. Apply 50 to 100 pounds of well-rotted barnyard manure (cow, hog, or horse) per 100 feet of row.    

Currants and Gooseberries

Apply about 1 cup of a complete fertilizer, such as 10-10-10, in a circular band around each plant in early spring. Manure is another option. Apply 1/2 to 1 bushel of well-rotted manure uniformly around each plant in late fall or early spring.    

Grapes

It is generally not necessary for home gardeners to fertilize grapes in Iowa. Fertilize grapevines only when plants exhibit weak growth or poor leaf color. Use a complete fertilizer, such as 10-10-10. Broadcast 1/2 pound around each plant. Too much nitrogen may promote excessive vegetative growth and delay vine and fruit maturity. The best time to fertilize is early spring. Do not fertilize grapevines in late spring or summer.    

Blueberries

Once established, apply 1/2 to 1 pound of ammonium sulfate per 100 square feet of garden area. Apply the material in broad bands around plants in early spring before budbreak. Do not fertilize after the bloom period. Ammonium sulfate supplies nitrogen to the plants and also helps to maintain soil acidity.   

Fruit Trees

Check tree growth to determine whether fruit trees need fertilization. Nonbearing fruit trees should grow approximately 15 to 30 inches per year. Bearing trees should produce 8 to 15 inches of new growth. (The actual amount of new growth will vary due to differences in varietal vigor.) 

It is generally not necessary to fertilize fruit trees, as most Iowa soils provide the nutrients needed for adequate growth. If the lawn in the vicinity of the fruit trees is fertilized on a regular basis, there should be no need to fertilize the trees. The fruit tree roots will absorb nutrients from the lawn fertilizer. Additional fertilizer may be excessive.    

Fruit trees with less-than-desirable growth may need fertilization. The recommended rate is 1/10 (0.10) pound of actual nitrogen per year of tree age. (Tree age is the number of years since the tree was planted in the home garden.) For example, a 5-year-old tree should receive 5/10 or 1/2 (0.50) pounds of nitrogen. Once trees reach 10 years old, do not apply more than one pound of actual nitrogen per tree.  

To determine how much fertilizer to apply, take the amount of nitrogen needed for the tree divided by the percent nitrogen in the fertilizer. (The first number in the fertilizer analysis indicates the percent nitrogen in the fertilizer.)  For example, to apply 0.50 pounds of nitrogen to the 5-year-old tree using a 10-2-6 fertilizer, divide 0.50 by 0.10 to get 5 pounds. Apply 5 pounds of 10-2-6 fertilizer to the tree to provide 0.50 pounds of nitrogen to the tree.

Uniformly broadcast the fertilizer in a circular band beginning about 2 to 3 feet from the trunk and extending out slightly beyond the dripline of the tree. 

Early spring is the best time to fertilize fruit trees. Applications can be made starting just before budbreak and are best completed by petal drop. Avoid fertilizing in late spring or summer, as this may stimulate late-summer growth that is more susceptible to winter injury. Always err on the side of less when it comes to fertilizer. Too much fertilizer produces excessive vegetative growth and inhibits fruiting.

More Information

• Fertilizing in the Home Garden
• Growing Strawberries in the Home Garden (publication)
• Growing Raspberries in the Home Garden (publication)
• Growing Currants and Gooseberries in the Home Garden
• Growing Grapes in the Home Garden (publication)
• Growing Blueberries in Iowa (publication)
• Growing Fruit in Iowa (publication)