To ensure proper growth, plants, like animals, need the essential elements of life: water and food, the latter from soil nutrients and fertilizer. Sometimes they get enough from their environment, but often they need a helping hand. Growers are usually attentive regarding water, but not always food. Adding the right type and amount of food is just as important as when and what you’re planting.
Water is essential when planting young trees and shrubs as they typically need more than is generally available while getting established. That’s not necessarily the case for fertilizer. Just the opposite is true.
Plants take up food – nutrients – through the interface between roots and soil. It takes time for that interface to become established. Roots first need to grow before they develop a symbiotic relationship with soil microbes or root microbiota. Most of a plant’s energy goes toward growth during its establishment phase, and applying fertilizer too soon can burn the tender roots and suppress root growth.
We at Chestnut Hill Outdoors have four generations of dirt wisdom when it comes to planting trees, and we go to great lengths to ensure our customers receive quality products. Through the Chestnut Hill Outdoors Learning Center and direct communication, we provide sound advice on planting, maintaining, and protecting trees and shrubs to ensure maximum growth and production. That’s why we recommend waiting a full year after planting before fertilizing year-old trees and at least two months after planting before fertilizing 2-year or older trees.
Choosing A Fertilizer
What fertilizer to use is an important consideration. The general recommendation is for a slow-release or time-release fertilizer. This gradually introduces micronutrients and microbes to the soil, so root systems can acclimate and adjust to local soil temperatures and conditions more easily.
There are several types to choose from: controlled-release fertilizers or CRFs rely on an innate mechanism within the fertilizer to release nutrients. Granular fertilizers are water-insoluble. They require water to dissolve, but the pellet structure prevents rapid leaching during rain events or routine watering. Rather than being water-based, like quick-release liquid fertilizers, water-soluble fertilizers release nutrients gradually. Last but not least is natural and organic fertilizers composed of materials like mulch, kelp, compost, and bone meal.
The fertilizer formulation is often less critical but can be an issue if certain nutrients are notably lacking. A simple soil test is the best and easiest way to determine the right mix. The local agricultural extension service can then evaluate test results and recommend fertilizer. It is essential to soil pH as it will indicate the level of acidity and how much or little lime (Nitrogen) is needed. You can also find more specific recommendations in the CHO Learning Center.
When To Fertilize
The best time to fertilize fruit trees – once they’re established – is during the growing season. Start in early spring (March-May) after bud break, when new growth begins, and continue until roughly June. Heavy summer rains can leach away much of the Nitrogen, which is highly soluble and an essential element for plant growth. Do not fertilize in the fall, as this can promote late-season tender growth that early frosts can damage.
How To Fertilize
Determining how and where to fertilize is somewhat intuitive if you know how plants grow. Root systems typically grow out under the tree canopy, which then gradually redistributes rainfall to the ground. Spread the fertilizer evenly throughout this area, avoiding the immediate (5-12-inch) area around the trunk. Simple spreading is effective, but you’ll get better results if you can mix the fertilizer in the top 1-3 inches of soil. Watering afterward or fertilizing just before a rain event will promote maximum absorption.
Humans use the term diet when reducing food intake, but it refers to what and how much you consume. Just like humans, if you provide plants with a proper diet of the right type and amount of food at the appropriate time, they’ll be much healthier and better able to provide a crop of nutritious food for you and the wild creatures on your land.