In This Article we will discuss the following: When to Fertilize fruit trees, How to Measure Growth, Choosing Your Fertilizer, How Much Fertilizer to Use, and Applying the Fertilizer in your specific applications.

To produce abundant fruit, different types of fruit trees need proper nutrition. Young trees require good nutrition to grow and yield a bountiful harvest, just like vegetables, flowers, and other plants. Maximize your growing season with our helpful video, where Tricia explains when to fertilize fruit trees, how much to use, and the best apple tree fertilizer for your needs. Take note of the information below to learn the 5 easy steps for fertilizing apple trees and start producing fruit from your grafted trees sooner with our guide.

Importance of Proper Fertilization

Impact on Fruit Yield

Proper fertilization is crucial for maximizing fruit yield in fruit trees, such as apple trees and other stone fruits. Knowing when to fertilize fruit trees is essential for optimal growth and productivity. Fruit trees benefit from balanced nutrients provided by fertilizers tailored to their needs. Organic fertilizers like chicken manure and compost contribute to steady growth and healthy fruit production without risking the negative effects of excess nitrogen, which can lead to issues such as fire blight or bitter pit.

When fertilizing apple trees, using the right apple tree fertilizer at the best time to fertilize—typically in early spring—promotes healthy vegetative growth. Conducting a soil test helps determine nutrient deficiencies, guiding the application of fertilizers such as calcium sprays or calcium nitrate to improve fruit size and overall crop quality. Proper fertilizing apple trees ensures robust development and a bountiful harvest.

Long-term Tree Health Benefits

Properly fertilizing fruit trees not only enhances current fruit production but also promotes long-term tree health benefits. By using organic fertilizers like compost or chicken manure, fruit trees—whether apple trees or other fruit trees—experience steady growth and improved nutrient uptake, which strengthens their resilience against diseases such as fire blight and disorders like bitter pit.

Understanding when to fertilize fruit trees is crucial for optimal results. Fertilizing young apple trees with organic fertilizer supports their early development and establishes strong root systems.

Regular soil testing, including checking soil pH, ensures that essential nutrients like calcium are maintained, fostering robust tree growth and larger, healthier fruits over successive growing seasons. This approach helps reduce issues like fruit drop and supports the overall longevity and productivity of mature fruit trees, encouraging optimal fruit size and quality.

Types of Fertilizers

Slow-Release vs. Quick-Release Fertilizers

To best fertilize fruit trees for a big harvest, understanding the types of fertilizers is crucial. Quick-release fertilizers provide an immediate nutrient boost, ideal for early spring when fruit trees require rapid vegetative growth and bud break.

However, they can risk over-fertilization if not applied carefully, potentially leading to excessive new growth at the expense of fruit production. In contrast, slow-release organic fertilizers, such as those incorporating wood chips or calcium chloride, release nutrients gradually over time, supporting sustained growth throughout the season.

These are beneficial in late spring to promote small fruits and ensure a balanced nutrient uptake without the risk of nutrient leaching or environmental impact.

Step 1: When to Fertilize Your Fruit Trees

Fruit trees that grow give us a rewarding crop in the summer and fall, but we need to feed them. Growing fruit trees can be an extremely rewarding experience when done well. Having an Established root system will help with nutrient uptake. The best time to fertilize is in the early spring, just before bud break. You can feed throughout the summer, but it is best to stop applying any nitrogen after July. 

Step 2: Measure to Decide if You Need to Fertilize

Not all fruit trees need to be fed every year, nor in the same amounts. If you feed them too much nitrogen, they will grow lots of leaves but give you very little fruit. Luckily, the tree can tell you what it needs, and when it's time to fertilize. Using organic nitrogen sources is recommended to prevent "burning".

Steps in Measuring the Previous Year's Growth

• First: Locate last year’s growth rings. The growth ring is the point on the branch where the fruit tree started growing in the previous season. The newest shoot growth that you will be measuring is often a different color than the rest of the branch.
• Second: Measure from the growth ring all the way to the end of the branch. Repeat these measurements at several spots around the fruit tree.
• Third: Calculate the average of these measurements. This is the previous season’s “annual growth” of the fruit tree.

Repeat this step for each of your fruit trees. Even if you have multiple fruit trees that are the same kind and age, they may not have grown equally. As a result, these trees may require different amounts of fertilizer. 

Note–if you have pruned your fruit tree significantly more than normal, so that you’ve removed over 20% of its canopy within the last year, don’t fertilize until the next year.

Check the Chart to Evaluate Growth

Finally, use this chart to evaluate your fruit tree’s annual growth. If the fruit tree’s growth rate is at the low end or below annual target growth, then you should fertilize the fruit tree this year. If your fruit tree’s growth rate is at the high end or above the annual target growth rate, you do not need to fertilize this year (but measure again next year in case that changes!).

• Peaches and nectarines (non-bearing young fruit trees) should grow 18"-24", mature bearing trees should grow 12"-18"
• Apples and pear trees (non-bearing young fruit) should grow 18"-30", mature bearing pears and non-spur type apples should grow 12"-18"
• Bearing spur apples should grow 6"-10"
• Plums and sweet cherries (non-bearing young fruit trees) should grow 22"-36", mature bearing trees should grow 8"
• Tart cherries (non-bearing young fruit trees) should grow 12"-24", bearing mature trees should grow 8"

Step Three: Choose the Right Fertilizer

• Fruit trees prefer an organic, high nitrogen fertilizer.
• Good organic fertilizers high in nitrogen include blood meal, soybean meal, composted chicken manure, cottonseed meal, and feather meal.
• There are also specially formulated fruit tree fertilizers available.
• In addition to nitrogen, fruit trees need other macro and micronutrients.
• Adding compost when you fertilize provides organic matter and trace minerals.
• Azomite or Cascade Remineralizing Soil Boost are excellent sources of trace minerals.
• A soil test, or soil sample, can reveal calcium deficiencies or the need for additional phosphorus, potassium, and other nutrients.
• Regular soil testing helps prevent issues like weak growth.
• For best results, fertilize in early summer to support ongoing development and productivity.

Step Four: Calculate how Much Fertilizer to Use

• More is not always better when it comes to fertilizing your fruit trees. Now that you know that your fruit tree needs fertilizer and you have picked the perfect fertilizer to use, you’ll need to determine the correct amount to use on each fruit tree.
• The amount of fertilizer you should use is based on the age or size of the fruit tree, and the nitrogen-value on the package.

Determining How Much Fertilizer to Use

• Planted trees need 0.10 pounds of “actual nitrogen” per year of age or per inch of trunk diameter (measured 1 foot above the ground).
• The maximum you should give a fruit tree in a year is 1 pound of actual nitrogen.
• For example, if your fruit tree has a trunk diameter of 5 inches (or if your tree is 5 years old), multiply 5 by 0.10 pounds of nitrogen, which equals 0.5 lb. This means that the fruit tree will need 0.5 lb of actual nitrogen.
• To apply this nitrogen, consider that “actual nitrogen” pounds is not as simple as just weighing out that amount of fertilizer because there is more in a fertilizer than just nitrogen.
• The NPK numbers on fertilizer show the percentage of nutrients per pound of fertilizer, not the actual amount. N, P, and K refer to nitrogen, phosphorus, and potassium.
• For example, if the N listed on the fertilizer package is 7 (meaning 7% nitrogen), such as with E.B. Stone's Fruit Tree fertilizer, then there is 0.07 pounds of actual nitrogen for every pound of fertilizer.
• To calculate how much fertilizer to apply, divide the amount of actual nitrogen the fruit tree needs by the amount of actual nitrogen per pound in the fertilizer.
• So, using the previous example, a five-year-old apple tree needs 0.5 lb of nitrogen. The E.B. Stone Fruit Tree Fertilizer has an N-value of 7 on the package, meaning it has 0.07 lb nitrogen per pound of fertilizer. Half a pound, or 0.5 lb, divided by 0.07 lb equals 7 lbs.
• The answer—7 pounds—is the amount of this fertilizer to apply to the fruit tree.
• For other types of fruit trees like pears and peaches, similar calculations apply. Consider incorporating additional nutrients such as calcium nitrate, potash magnesia, or Sul-Po-Mag if needed, based on a soil test.
• Applying fertilizers in the fall can help support root growth and prepare the tree for the next growing season. Gardening practices should include regular adjustments based on soil conditions and previous year's performance.

Step Five: Applying the Fertilizer

• To help the fruit tree “eat” the fertilizer most efficiently, apply the fertilizer evenly. Start a foot away from the trunk and continue all the way to the “drip line.” The drip line is the perimeter of the tree’s farthest reaching branches.
• The easiest way to do this is simply by spreading the fertilizer on the ground and raking it in.
• Digging a series of small holes on the soil surface is another method of applying fertilizer. It is a bit more work, but it best ensures the fertilizer is getting to the fruit tree roots, especially when using a fertilizer containing less-soluble nutrients like phosphorus and mycorrhizae.
• Dig the holes six inches down and 12” to 18” apart, throughout the same area as you would have spread the fertilizer. To make the digging job easy, you can use an auger attachment with a cordless drill. Sprinkle a little bit of fertilizer in each hole until it is used up.
• Once you have finished fertilizing, spread an inch-deep layer of compost around the fruit tree and water well.
• Soil ph needs to be maintained so that the tree can "uptake" certain nutrients.

Conclusion

Fertilizing fruit trees is a critical practice for achieving a bountiful harvest and ensuring long-term tree health. By following the guidelines outlined in this article, you can optimize the growth and productivity of your fruit trees. Remember, the best time to fertilize fruit trees is in early spring, just before bud break, to support robust annual growth and a fruitful growing season.

Choosing the right fertilizer is essential; organic fertilizers, such as composted chicken manure or blood meal, provide a steady release of nutrients and are less likely to cause issues compared to synthetic options. For a high nitrogen fertilizer, ensure it is used in moderation to avoid the pitfalls of too much fertilizer, which can lead to excessive leaf growth at the expense of fruit production. It's important to consider the nutritional needs of your trees and avoid over-fertilizing, which can exacerbate problems like frost damage or boron deficiency.

Regularly measure the annual growth of your trees and adjust the amount of fertilizer accordingly. For example, applying one pound of fertilizer per tree can be effective, but it should be done with care to prevent nutrient imbalances. Ammonium sulfate can be beneficial, but be cautious to avoid disrupting the balance of nutrients. Always base your fertilization strategy on soil tests and the specific needs of your trees, adjusting for factors such as whether they are actively growing or in a dormant phase.

In late summer or late winter, re-evaluate your fertilization plan and make necessary adjustments based on the previous year's performance. With these practices, you'll maximize the potential of your fruit trees and enjoy a thriving, productive orchard.

To get started with high-quality fruit and nut trees, visit Grow Organic for a wide selection of fruit and nut trees for sale.

FAQs About How to Best Fertilize Your Fruit Trees for a Big Harvest

• What is the importance of fertilizing fruit trees?

  • Fertilizing fruit trees is crucial for promoting healthy growth and maximizing fruit production. Properly balanced nutrients help in achieving optimal fruit size and quality, ensuring robust development of roots, branches, and flowers.

• How often should I fertilize my fruit trees?

  • Fruit trees generally benefit from fertilization once or twice a year. The timing and frequency may vary based on tree age, soil conditions, and specific fertilizer used. Fertilizing in early spring, just before bud break, and possibly again in late summer can support ongoing growth. For best results, adjust based on previous year’s performance and specific tree needs.

• When to fertilize fruit trees in California?

  • In California, the best time to fertilize fruit trees is typically in early spring, just before bud break, and possibly again in late summer. The specific timing may vary based on local climate and soil conditions. Regular soil testing can provide guidance tailored to your region.

• When should I fertilize apple trees?

  • Apple trees should generally be fertilized in early spring, just before bud break, to support healthy vegetative growth and fruit development. A second application in late summer can help sustain growth and prepare the tree for the next growing season. Adjust based on soil test results and the tree’s performance in the previous year.

• What are the best fertilizers for fruit trees?

  • Organic fertilizers like compost and chicken manure are excellent choices for fruit trees as they provide slow-release nutrients without risking over-fertilization. Additionally, balanced fertilizers containing essential nutrients such as calcium, nitrogen, and potassium support steady growth and good crop yields. For specific needs, consider products like Sul-Po-Mag or other fertilizers that address nutrient deficiencies.

• Is 16-16-16 fertilizer good for fruit trees?

  • A 16-16-16 fertilizer provides a balanced mix of nitrogen, phosphorus, and potassium. While it can be beneficial, it's important to tailor fertilizer choices to the specific needs of your fruit trees. Depending on your soil test results, you may need additional nutrients like calcium or specialized fertilizers.

• What is the best compost for fruit trees?

  • The best compost for fruit trees is well-decomposed and rich in organic matter. Compost made from a mix of plant materials and manure, such as composted chicken manure or a blend of kitchen scraps and yard waste, is ideal. It improves soil structure, provides essential nutrients, and enhances overall tree health.

• How can I prevent issues like fire blight and bitter pit through fertilization?

  • By avoiding excessive nitrogen and ensuring proper nutrient balance with calcium sprays or calcium nitrate, you can help prevent common tree disorders like fire blight and bitter pit. Regular soil testing helps in adjusting fertilizer applications to address specific nutrient deficiencies and maintain healthy growth.

• How does fertilization impact the size and quality of fruit?

  • Proper fertilization enhances fruit size and quality by promoting healthy tree growth and optimizing nutrient uptake. This results in larger, more flavorful fruits that are less prone to diseases and disorders. Fertilizing in winter or early spring ensures that the trees have the nutrients they need as buds begin to swell and develop.

• What role does mulching play in fruit tree care?

  • Mulching helps retain soil moisture, suppress weeds, and regulate soil temperature. It also adds organic matter as it decomposes, which improves soil structure and nutrient content, benefiting the roots of your fruit trees.

• How can I manage nutrient levels effectively?

  • Regular soil tests can help you understand nutrient levels and adjust your fertilization practices accordingly. Using small amounts of balanced fertilizer, such as those containing Sul-Po-Mag, can help correct deficiencies and avoid over-fertilization.

• What should I do if I notice weak growth or poor fruit production?

  • Weak growth or poor fruit production may indicate nutrient imbalances. Re-evaluate your fertilization strategy and consider adding specific nutrients or adjusting application rates based on soil test results. Ensuring proper care and addressing issues like weed competition and soil health can also improve outcomes.

• How does planting and garden maintenance affect fruit tree health?

  • Proper planting techniques and ongoing garden maintenance are essential for fruit tree health. Ensure adequate spacing, proper soil preparation, and regular pruning of branches to promote good air circulation and sunlight exposure. Effective gardening practices, including managing weeds and maintaining mulch, contribute to overall tree vitality and productivity.

Resources

• For more information on all aspects of fertilizing apple and fruit trees—From selecting and planting a bare root, pruning, controlling pests, and even how to preserve your harvest—browse our videos and articles in Fruit Tree Central. Some staff-favorite books on fruit trees are The Home Orchard from UC Davis, along with The Fruit Gardener's Bible.
• Keep on living the dream with your organic orchard, now that you know when and how to fertilize your fruit trees.