Oak trees need special care at times. The best way to know if a tree is not receiving sufficient nutrients from the soil is to take a sample and test it. If the soil is insufficient, organic and inorganic fertilizer can be applied to improve the health of the tree.
Oaks produce wood that is durable and resistant to insects and fungal infection. That wood is commonly used to make furniture and floors; it is used for wine barrels because of its ability to contribute to the wine’s taste, colour and smell. Oak leaves and acorns are toxic to most animals (except domestic pigs), due to a high amount of tannic acid found in them.
Best Time to Fertilize
Oak trees are hard and their shed leaves decompose on the ground. This process adds nutrients to the surrounding soil. Fertilizer can boost growth and production of acorns. The best time to add fertilizer is at the start of spring; oaks grow very fast during warmer weather and you want to provide nutrients before a growth spurt.
Nutrient Ratios
The nutrient ratio is a key component in fertilizing. Experts recommend using the “N-P-K” system: The percentage a fertilizer contains of Nitrogen (N) to Phosphorus (P) to Potassium (K). For oaks, a ratio of either 12-4-8 (12% Nitrogen, 4% Phosphorus, and 8% Potassium) or 12-6-6 is recommended. A fertilizer that releases nitrogen too quickly can cause more harm to the soil and tree than good.
How to Fertilize
Spread fertilizer evenly so nutrients are evenly distributed. Then apply mulch to the surrounding soil. Mulch has three main benefits:
- Prevents weed growth
- Prevents loss of soil moisture
- Adds organic nutrients to the soil
At Great Northern ReGreenery we care for any trees, particularly oaks. Our experts are trained to help you select trees that will thrive in the Canadian landscape and remain healthy and productive. For more inquiries please call (905) 775-7444 or (705) 458-4600.