Fertilizing trees is essential for maintaining their health and promoting vigorous growth. However, improper application can lead to wasted resources and potential harm to the tree. This guide provides a comprehensive approach to correct tree fertilization, ensuring that trees receive the necessary nutrients effectively and safely.

**Understanding the Root System**
Before you start fertilizing, it’s important to understand a tree’s root system. Most of the tree’s absorbing roots, including the critical root hairs, are not located near the trunk but extend outward beneath the tree’s canopy, often reaching beyond the drip line. These roots are key for nutrient uptake.

**Step 1: Assessing the Need for Fertilization**
– **Soil Testing:**
Begin by testing the soil to identify nutrient deficiencies. This helps in selecting the appropriate type of fertilizer.
– **Observation:**
Look for signs of nutrient deficiency in the tree, such as discolored leaves, stunted growth, or premature leaf drop.

**Step 2: Choosing the Right Fertilizer**
– **Type:**
Select a slow-release, granular fertilizer that aligns with the nutrient needs identified in your soil test.
– **Formula:**
Generally, a balanced N-P-K (Nitrogen, Phosphorus, Potassium) ratio is recommended, unless the soil test indicates a different requirement.

**Step 3: Proper Fertilization Technique**
– **Where to Fertilize:**
Apply fertilizer in the area where the root hairs are most active, which is typically under the tree’s canopy and extending just beyond the drip line. Avoid applying fertilizer directly at the base of the trunk.
– **How to Apply:**
– **Broadcast Method:** Evenly spread the granules over the soil surface within the root zone.
– **Fertilizer Wells:** Create shallow wells (4-6 inches deep) around the drip line and place the fertilizer directly into these wells for deeper nutrient penetration.
– **Watering:**
After applying the fertilizer, water the area thoroughly to help nutrients penetrate the soil where the roots can access them. Avoid water pooling around the trunk.

**Additional Tips for Tree Care**
– **Watering Practices:**
– Prevent water from touching the trunk directly. Use mulch or a dirt barrier to divert water away from the trunk.
– Ensure proper soil drainage to avoid root rot. In poorly draining soil, overhydration can be problematic.
– During dry or hot weather, water trees in intervals rather than flooding the area to prevent overhydration.

Following these guidelines will help you fertilize your trees effectively, supporting their health and ensuring they grow robustly.