What Kind of Fertilizer for a Young Oak Tree?

Fertilizer for Seedlings

• The Oklahoma Cooperative Extension Service recommends fertilizing oak seedlings a month after germination. Dilute a liquid fertilizer and apply every week. A fertilizer intended for houseplants works well, too. Dilute this prior to application. When using a household fertilizer, make sure the amount of nitrogen is similar to or more than the amount of potassium and phosphorus, the three primary nutrients essential for plant growth. A good choice would bean all-purpose fertilizer with the formulation of 24-8-16, as suggested by the Mississippi State University Extension.

Fertilizer for Young Trees

• Fertilize younger trees with organic or inorganic fertilizers. Inorganic fertilizers, also referred to as synthetic or manmade fertilizers, are more soluble compared with organic fertilizers, making nutrients instantly available to the tree. Organic fertilizers usually are obtained from animal sources and need to decompose in the soil before the nutrients are available for plant use. A combination of both types of fertilizers is recommended as this keeps trees fertilized for an extended period of time. Conducting a soil test is the best way to determine soil deficiencies and to choose fertilizer formulation accordingly.

Fertilizer Rates

• Use minimal amounts of fertilizer on young trees, especially after they have been transplanted to the ground. Excessive use of fertilizer increases stress on plants. Use about 1 tsp. of a nitrogen-based fertilizer or 1 tbsp. of a balanced fertilizer in the formulation of 10-10-10. As trees get sturdier and taller, increase fertilizer amount to 2 to 3 tbsp. The recommended time to fertilize trees is during the active growth season in spring.

Fertilizing Suggestions

• Fertilize young oak trees once every year. Given the long life of oaks, trees 15 to 20 years old still are considered "young." Clear all weeds and grasses in a diameter of 3 to 4 feet around tree. Apply fertilizer evenly on soil in this area. Avoid fertilizing between late summer and midfall. This promotes soft, succulent growth that becomes highly prone to winter damage as it has not had time to harden sufficiently. In case the oak tree is visibly suffering from a nutrient deficiency, fertilize after the first frost but before freezing weather. This is to alleviate cold related stress on already weak trees suffering from low nutrients levels.