9 Fertilizers That Will Make Your Fruit Trees Thrive—and Produce More

Fruit tree fertilizer isn’t one-size-fits-all—especially if you want a harvest worth bragging about. Before you feed your trees, it’s important to understand what your soil needs, what your tree is asking for, and how to apply nutrients responsibly. Here, we talked with gardening experts about the best fertilizers for fruit trees—from time-tested compost to targeted organic meals—and how you can effectively apply them.

Start With a Soil Test

Before you start, the most crucial step is testing your soil.

“Start with a lab soil test,” says Mary Jane Duford, master gardener and permaculture designer. “It will show what's missing and give clear instructions on what to add.”

A soil test evaluates macronutrient levels (nitrogen, phosphorus, and potassium), soil pH, organic matter, and sometimes micronutrient availability. “The pH of the soil controls how available nutrients are to plants, even if they're present in ample quantities,” says Jonathan Foster, a horticulturist at the University of Maine Cooperative Extension.

Experts recommend contacting your local cooperative extension service for a professional test. From there, you can make a more informed decision on which fertilizer would most benefit your fruit trees.

Organic vs. Synthetic Fertilizers

Before choosing a fertilizer, it's important to understand the differences between organic and synthetic varieties. Each has its advantages, depending on your goals and the needs of your soil and trees.

“Synthetic fertilizers have a larger, quicker impact, but disappear rapidly in soil and rain. Plants get a big, windfall burst of nutrients that they usually respond to very well, but anything they can't quickly use pretty much runs off into groundwater,” says Foster. They’re easy to apply, widely available, and deliver visible results fast—especially for nitrogen-hungry fruit trees.

By contrast, organic fertilizers—like compost, blood meal, fish emulsion, and feather meal—release nutrients slowly as they break down. “They either stay in the soil as a natural time release or decompose into organic matter,” he adds. This improves the soil’s texture, water retention, and microbial life, creating long-term benefits for the tree.

Timing

“Most fruit plants are fertilized in spring at flowering time,” says Jon Traunfeld, director of the home and garden information center at the University of Maryland Extension.

Leslie Halleck, a certified professional horticulturist, recommends waiting three months before the first application. You can use a root stimulator in the meantime.

Citrus trees are a different story entirely. “They are typically fertilized during the active growth season—spring, summer, and fall—with a 2-1-1 ratio or a 1-1-1 ratio fertilizer," she says.

Which Should You Choose?

Synthetic fertilizers can provide a quick boost, especially when correcting a known nutrient deficiency. But for ongoing maintenance, many experts recommend organic fertilizers. This is because they release their nutrients more slowly, so there's less of a risk of overfeeding—and they help protect the soil biology.

Whatever you choose, use it intentionally: “Anyone just impulse purchasing a jug of fertilizer and soaking it around without precision is wasting the majority of it," says Foster. "It's problematic financially, horticulturally, and ecologically.”

Whether you're looking for quick or long-term results, there are many options to choose from.

Balanced Granular Fertilizer

A balanced granular fertilizer, like 10-10-10 or 12-12-12, offers the same amount of nitrogen (N), phosphorus (P), and potassium (K). It’s a solid go-to when you don’t have a soil test yet, or when your trees need across-the-board support.

“While they are not targeted towards any specific nutrient deficiency, these fertilizers ensure no major nutrient is lacking and are a good place to start," adds Duford.

Since this is a synthetic fertilizer, look for slow-release versions to avoid overfeeding. “Too much can produce overly succulent growth that's attractive to insect pests,” warns Traunfeld.

Application

Halleck recommends using this fertilizer in early spring, four to six weeks before bud break. This will help support shoot, flower, and fruit development. “It wouldn’t hurt to choose a fertilizer with a little calcium added as well,” she notes.

Scatter the fertilizer evenly under the tree's canopy, but keep it away from the trunk. Then, water it in well. “The entire root zone should be fertilized ... not just the area closest to the trunk,” Traunfeld adds.

Compost or Aged Manure

These natural, organic soil amendments provide a gentle blend of nutrients, enhance soil structure, and promote microbial health.

“It’s a long-term management dose that slowly maintains both macronutrients and, most of the time, micronutrients," says Foster. "It improves soil quality in other ways as it decomposes in place.”

Plus, compost won't risk burning tree roots like a synthetic fertilizer might. Keep in mind, though, that this fertilizer's nutrient content can vary widely, depending on the source.

Application

Apply once a year, either in late fall or early spring. Spread a 2- to 3-inch layer across the root zone, but keep it a few inches away from the trunk. Compost can also be used year-round as mulch.

“Topdress by applying 1/2 to 1 inch of compost under the tree’s canopy or dripline each year,” Traunfeld says. Fertilizers applied to nearby turf grass can also indirectly benefit the tree.

Blood Meal

Blood meal is a fast-acting organic fertilizer made from dried animal blood. It’s packed with nitrogen, with an NPK of 12-0-0, and acts quickly.

“Use blood meal if a tree has pale older leaves or weak shoot growth," says Duford. "These signs often point to nitrogen deficiency."

It does have a distinct smell though, so use it cautiously in enclosed gardens.

Application

Apply in early spring as new growth begins. Scatter it under the canopy (not against the trunk), and mix lightly into the top inch of soil. For midseason boosts, use a smaller dose.

Scratch it gently into the top layer of soil and water it in well, advises Foster. It works fast, but it can burn plants if it's not used in the proper amount.

Feather Meal

Feather meal is a slow-release organic fertilizer made from processed poultry feathers that have been dehydrated into a powder. It’s a rich nitrogen source, typically with an NPK ratio of around 12-0-0, but it can be slow to take effect. It’s ideal for fruit trees that need a long-lasting boost of nitrogen.

This fertilizer is less likely to burn plants than fast-acting ones, but results will take longer to appear. Use it when you’re seeking a season-long feed, not just a quick correction.

Application

Apply feather meal in early spring under the drip line, lightly cultivating it into the top few inches of soil. Its slow-release nature makes it particularly well-suited for young trees, as well as those growing in sandy or nutrient-depleted soils.

Bone Meal

Bone meal is made from ground and dehydrated animal bones. Its typical NPK ratio is around 3-15-0.

“Fruit trees don't need a lot of phosphorus, but they cannot grow well without it,” says Duford. Bone meal provides a slow-release source of phosphorus, which supports strong root systems and early fruit development.

“Phosphorus doesn’t move easily in the soil,” she notes. That’s why it’s best to add bone meal during planting and mix it directly into the root zone.

Since phosphorus accumulates in soil over time, don’t apply it regularly unless a test shows a deficiency. Too much can block the uptake of other essential nutrients, like calcium and magnesium.

Application

Scratch bone meal into the soil near the root zone, being careful not to disturb the roots of established trees.

Fish Emulsion

Fish emulsion is a liquid organic fertilizer made from processed fish waste. It typically has an NPK ratio of around 4-1-1 or 5-2-2.

“Fish emulsion is fine to use,” says Traunfeld. “The nutrients are available more quickly to plants. Since it's mixed with water and applied as a liquid fertilizer, it must be applied more than once per season.”

“[It's] a broader, milder fertilizer than the meals above," says Foster. However, "Excess usage will result in waste washing out.”

However, keep in mind that while fish emulsion is effective, it does have an odor. “If you're sensitive to smells, perhaps consider something else,” he says. Apply on cool days or just before rain to help dissipate the scent.

Application

Dilute fish emulsion according to label instructions and apply as a soil drench around the tree’s drip line. Reapply every few weeks during the growing season—especially for young or nutrient-deficient trees.

Plant-Based Meals

Alfalfa meal and soybean meal are both plant-based, organic fertilizers that gently boost nitrogen. Alfalfa meal typically has an NPK of 2-1-2, while soybean meal is around 7-2-1.

According to experts, these meals are reliable, sustainable choices for gardeners who prefer vegetarian options or who want to avoid animal byproducts. They're a “good, plant-based source of nitrogen, with slightly lower impact,” says Foster. They help improve soil structure and feed microbial life while also delivering essential nutrients.

Alfalfa meal may contain viable seeds, so keep an eye out for unintended sprouts. Both fertilizers are best used when soil temperatures are warm enough to support microbial activity.

While not as potent as animal-based options, they are steady performers and a great supplement to compost or aged manure.

Application

Apply either meal in early spring. Spread under the canopy and work it lightly into the soil. Alfalfa meal can also be brewed into a compost tea. Soybean meal decomposes gradually, making it an ideal option for long-term soil health.

Fertilizer Spikes

Fertilizer spikes are pre-measured sticks that release nutrients slowly into the soil.

“Many gardeners choose spikes because they don't require measuring or spreading,” says Duford. “This makes them simple to use and popular for low-maintenance care.”

“One drawback is the uneven nutrient distribution,” she notes. Traunfeld adds that spikes tend to concentrate nutrients in a small area and may not feed the full root zone.

Application

Insert spikes near the tree’s drip line (not right at the trunk) in spring and again in fall, if needed. Follow label instructions closely.

Boron and Zinc Micronutrient Supplements

Small amounts of boron and zinc can have a significant impact on fruit set and growth.

“Some fruit trees struggle to absorb micronutrients in soil with high pH or excess calcium,” says Duford. “Boron and zinc are two of the most important nutrients for fruit tree health.”

Boron Application

If a soil test confirms low boron, mix 1 tablespoon of Borax into 2 gallons of water and apply under the canopy in early spring or fall. “Too much can poison the tree,” Duford warns.

Zinc Application

Zinc is best applied as a foliar spray. Alternatively, mix a small amount of zinc sulfate into the root zone soil and water it in. “Do not exceed the recommended dose,” Duford adds.