Tree Fertilization: The Single Best Piece of Autumn Advice for Trees

Tree fertilization and soil care in autumn dramatically improve growing conditions for your trees and shrubs.  In fact, you might be surprised to learn that soil conditions in urban and suburban environments are often inhospitable to trees. That’s right. The suburban/urban growing environment is vastly different than the ideal conditions found in nature. As such, trees growing in landscapes on residential or commercial properties often lack adequate nutrients and organic matter. Compacted soil, restricted root zones and competition with turf for nutrients are just a few of the stresses these trees are under. 

Tree Fertilization for Healthy Growth

Unable to access the nutrients they need, trees will struggle. They grow more slowly. Their foliage is smaller and off-color or yellowing. Leaves die and fall unseasonably. Insect and disease problems occur more frequently.

yellowing of maple leaves associated with micronutrient deficiency
Yellowing of maple leaves associated with a micronutrient deficiency.

The best autumn advice for healthy trees is this: get a soil test! Find out what is, and isn’t, in the soil where your trees and shrubs are living. With a soil test, fertilization can accurately address any deficiencies.  Overall, trees will be healthier with full canopies and vibrant color.  These trees will be better able to withstand stress and the unpredictable weather of winter.

tree fertilization
Fertilization ensures trees and shrubs have the nutrients needed for healthy growth.

Unearthing What’s in the Soil

Even though it’s mostly hidden underground, soil is not a mystery. It contains macronutrients – nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur – as well as micronutrients like iron and zinc. These nutrients are necessary for plant growth, but not always present at appropriate levels. Further, certain soil conditions like texture or pH level may make it difficult for plants to access those nutrients that are available.

Nutrient levels and soil characteristics will vary from site to site, and may even differ on the same property. The only sure way to find out about the soil on a specific property is through a soil test. A soil sample is collected from beneath the trees or shrubs and to determine exact nutrient levels, pH level, organic matter present and nutrient retention capacity.

soil sample for testing
A Plant Health Care Specialist collects a soil sample for testing and analysis.

Tried and Tested

If you fertilize without a soil test, it’s very possible you’ll see no results or, at least not the best possible results. Not only will you waste your investment, but worse, you could harm soil or plants in the landscape through misapplication. Add certain nitrogen to a plant with aphids or mites and your infestation may escalate. Create an imbalance of nutrient levels and see your turf suffer as it competes with trees to uptake what’s available.

With soil testing, you can identify specific nutrient deficiencies as well as problems with pH level or amount of organic matter present. That means tree fertilization and soil amendments can be tailored to effectively address problems instead of squandering money and creating new issues.

Timing for Fertilization is Key

The results of a soil test combined with horticultural knowledge provide precise, scientific data that can be used to improve plant health and appearance – if soil treatments are timed correctly. Autumn is an ideal time for this work.  In this season, you can address two vital needs at once. First, in autumn most trees don’t need nutrients for new foliage growth. They can instead use the nutrients from tree fertilization for vital root development. Secondly, excess nutrients can be stored so they are immediately available when spring’s growth begins.

When you have the right information, you can make the right decisions. Soil testing provides that information and guides the best decisions for fertilization in autumn.

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