Types of Winter Fertilizer for the Lawn

green lawn with frost in sunlight

Most conscientious gardeners will want to treat their lawn with a winter fertilizer to prepare it for the cold months ahead. This will give the lawn the nutrients that it needs to promote growth and keep it healthy during the winter weather. There are several different types of fertilizer available on the market depending on the climate and soil type. These types of fertilizer are often called “winterizers.” You will need to pick a winter fertilizer that is right for your lawn, containing adequate levels of plant nutrients.

Balance of Main Plant Nutrients

There are three main nutrients that your lawn needs to promote growth. These are nitrogen (N), which promotes leaf growth, phosphorus (P) which helps root growth, and potassium (K) which helps flowering and fruiting.

To help you choose the right fertilizer to help your lawn through winter, check the manufacturer’s packaging that will show the balance of these nutrients as an NPK code. For instance an NPK of 10-10-10 contains 10 percent nitrogen, 10 percent oxides of phosphorus and 10 percent oxides of potassium. To promote healthy growth of your lawn over winter you should choose a fertilizer that has an NPK suitable for your soil type and climate.

Slow-Release Fertilizers

Slow-release fertilizers have a higher level of nitrogen that is released gradually to help stimulate early grass growth in the spring and a thick healthy lawn. A typical NPK for this type of fertilizer is 20-2-6. This type of fertilizer should be applied before the soil temperature drops below 50 degrees F. If the fertilizer is applied below this temperature, the grass will already be dormant and will be unable to use the nutrients. Extra potassium is often put in this type of fertilizer to help promote hardy root development.

High Level Potassium Fertilizers

Winter fertilizers with a high level of potassium will help promote root hardiness. This type of fertilizer will have a typical NPK of around 10-0-15 and is suitable on all types of grasses.

Natural Fertilizers

Organic fertilizers are available that are typically made of either fish blood and bone meal, or pellet chicken manure. The nutrient content of these can be variable but will typically be around 5-5-5. These types of fertilizers can be raked into the lawn in the fall to help maintain the level of nutrients needed.

Potash Fertilizers

Potash fertilizers are available for your lawn that stimulate turf growth and help repair any damage the sun may have caused over the summer months. These should be applied in the fall before the winter sets in to help the turf recover before dormancy. This type of winter fertilizer will typically contain high levels of nitrogen to promote repair. They should be applied at a rate of 0.5kg of nitrogen per 100m2.

General Fertilizer Advice

Whatever type of winter fertilizer you choose for your lawn, make sure you read the manufacturer’s instructions carefully as overdosing may cause root damage which can be irreparable. You should also wear gloves and avoid inhaling any airborne particles when handling any fertilizer.