What’s Best for Your Commercial Trees: Deep Root vs. Surface Fertilization

Fertilizing trees may sound simple, but for your commercial property, pairing the right method with the right timing can make all the difference. Shallow surface applications might seem convenient, but they don’t always deliver nutrients where trees need them most. On the other hand, deep root fertilization targets the critical root zone for long-term health, but only when done correctly and at the right time of year.

Read on to get to know the ins and outs of deep root vs. surface fertilization, explore the pros and cons of each method, and learn when it makes the most sense to bring in a professional for commercial tree feeding.

How Each Fertilization Method Works

When it comes to delivering nutrients to commercial trees, not all fertilization methods are equally as effective. While both surface and deep root techniques aim to improve tree health, the way they function are significantly different—and so are the results they deliver.

Understanding the fundamentals of deep root vs. surface fertilization is the first step to choosing the right approach for your property.

Surface fertilization is the more familiar option. It involves applying granular or liquid nutrients directly to the soil’s surface or turf layer. These nutrients gradually leach into the topsoil and are absorbed by the upper portion of the root system. While this method can support light feeding and turf-adjacent trees, it’s less effective for delivering nutrients deep into the soil.

Deep root fertilization (DRF), on the other hand, uses a soil injection tool to deliver a nutrient-rich solution directly into the tree’s root zone. The goal is to bypass turf and compacted topsoil, reaching the fine, fibrous roots responsible for nutrient uptake. These injections are made in a grid pattern throughout the drip line, ensuring even coverage and targeted support.

Here’s a quick breakdown of how the two methods compare:

Surface Fertilization:
- Easier to apply with standard landscaping tools
- Suitable for turf-blended areas and general-purpose feeding
- Slower and more shallow absorption
- Greater risk of runoff or loss in compacted soil

Deep Root Fertilization:
- Requires specialized equipment and training
- Delivers nutrients directly to the root system
- Enhances long-term health and soil conditions
- Better suited for mature trees, stressed landscapes, and high-value properties

The key takeaway? Deep root vs. surface fertilization isn’t just a question of method, it’s a strategic decision based on the condition of the soil, the health of the trees, and the goals for growth or recovery.

When Each Method Makes Sense in Commercial Settings

Both fertilization methods have their place in a well-managed commercial landscape, but the key is matching the method to the property’s goals, soil conditions, and seasonal timing.

Knowing when to use deep root vs. surface fertilization can help maximize the health and longevity of your trees while minimizing unnecessary costs or risks.

Surface vs. Deep Root: Matching the Method to the Site

Surface fertilization is generally best suited for low-stress environments, young or shallow-rooted trees, or areas where turf is a priority. If your property requires routine maintenance or general nutrient support without specific signs of deficiency, surface treatments can be a simple, effective solution.

Deep root fertilization, on the other hand, offers a more targeted approach. For commercial properties with mature trees, compacted soils, or trees showing signs of stress or decline, this method delivers significant advantages. By injecting nutrients directly into the active root zone, DRF bypasses barriers that surface methods can’t overcome.

Deep Root Feeding Benefits and the Role of Timing

Among the top deep root feeding benefits are:

Enhanced nutrient uptake in dense or dry soils
Improved oxygenation and microbial activity in the root zone
Long-term support for tree health, canopy fullness, and stress tolerance
Reduced competition from turfgrass and surface-level plants

That said, the season and the objective matter just as much as the method itself. For example:

Spring deep root fertilization encourages tip and top growth, which is ideal for improving visual canopy appeal or pushing recovery after winter dormancy.
Fall deep root fertilization supports deeper root development, which enhances drought resilience and prepares trees for winter stress.
Summer, however, is not the time for either application, especially if soils are dry. Applying fertilizer in drought conditions can shock trees and cause further decline.

Both surface and deep root fertilization have a role to play, but DRF offers distinct advantages when long-term root health, stress recovery, or compacted soil conditions are the main concern. For commercial landscapes where trees are key assets, DRF is often the better investment—just not at the wrong time.

Understanding when and how to fertilize is only one part of the equation. If your trees are already showing signs of stress, it might be time for a closer look. Explore the warning signs your trees need professional care this summer to stay ahead of costly damage.

Common Fertilization Mistakes to Avoid

Even with the best intentions, fertilizing trees improperly can do more harm than good, especially on high-visibility commercial properties where appearance and longevity matter.

Here are some of the most common missteps:

Fertilizing during drought conditions: Applying nutrients when soil is dry can backfire. Fertilizer is salt-based, and without adequate moisture, it can draw water away from roots, causing stress or even shock. Always avoid fertilizing during extended dry periods.
Applying deep root treatments in summer: Summer isn’t the time for deep root fertilization. Trees are already under heat stress, and nutrient absorption is minimal. Instead, use this season to plan for optimal application in the fall or spring.
Choosing the wrong method for your goals: Surface fertilization won’t solve deep-root nutrient deficiencies, and deep root treatments aren’t necessary for young, healthy trees in good soil. Matching the method to your objectives is key.
Over-fertilizing or using the wrong formula: More isn’t better. Excess nutrients can burn roots, upset soil chemistry, or trigger unbalanced growth. A qualified arborist can help select the right formula and timing for your property.

By steering clear of these pitfalls, commercial property managers can protect their investment and support stronger, more resilient trees year-round.

Why Strategic Fertilization Pays Off

For commercial properties, fertilization isn’t just about keeping trees green. The right fertilization approach can help trees better resist stress, look more presentable year-round, and require fewer emergency services.

Deep root feeding benefits go beyond what surface applications can offer. When done at the right time of year and with proper technique, this method supports:

Stronger, deeper root systems that improve drought tolerance and structural stability
More efficient nutrient uptake, especially in compacted or poor-quality soils
Greater resistance to pests and disease due to improved overall tree health

But results depend heavily on execution. Timing, soil conditions, and species type all affect how well a tree responds to fertilization. That’s why commercial property managers should always consult an arborist when developing a plan for deep root applications.

A certified arborist can help you:

Evaluate soil health to tailor the right treatment
Choose the ideal fertilization window for your property goals
Avoid costly mistakes like fertilizing during a drought or applying the wrong formula

By investing in expert guidance, you not only maximize the ROI of your commercial tree feeding efforts, you also reduce the risk of decline, storm damage, or premature removals.

Plan Ahead for Healthier, Stronger Trees With Help From MTS

Don’t wait until your trees show signs of decline. Partner with Meyer Tree Service to create a custom deep root fertilization plan that supports your commercial landscape’s long-term success. Our certified arborists will assess your property’s needs and recommend the right timing and approach for optimal results. Let’s get your fall fertilization plan in motion today.