Fertilizing your lawn

To keep a lawn looking thick and lush, you need a timetable for feeding it and replacing lost nutrients. These nutrients are lost for three main reasons. Firstly, much of the nutrients are expended through the growing season. Secondly, mowing reduces the nutrient level in the grass. Thirdly, any trees or other large shrubs will rob some of the nutrients in the soil.

To replace these nutrients, we need to consider adding various things to the lawn at timely intervals. These include nitrogen, phosphates and potash.

Nitrogen (N)

Nitrogen is the most important nutrient in lawn fertilization. It helps grow a dense, thick lawn, by stimulating the grass plant growth, and keeps the grass green. This is the lawn food that is depleted most rapidly, but applying too much can create too much top growth and increase the need for mowing.

The approach of most homeowners is to fertilize in spring and summer. Some is needed at this time, but over-fertilizing will unnecessarily increase the amount of mowing required and can cause disease. A better approach is to consider fertilizing in the fall or late fall. At this time of the year, fertilizing will produce more root mass and increase its depth. This makes for a healthier grass plant that is more resistant to heat and drought come the summer months. Weed problems are also reduced, as is the risk of disease. The big bonus however is in the slowing of top growth, which means less mowing in spring and summer.

When purchasing a fertilizer, look to see what part of the nitrogen element is water soluble and what part is water insoluble. Water soluble nitrogen is available much more quickly to the grass plant. This is the principle component of fast release nitrogen fertilizer. It will produce quick results and is suitable for use during cool weather. Slow release, the water insoluble part, is important in reducing rapid grass top growth.

A good simple approach, which will vary with your climate, is to apply a moderate amount of nitrogen fertilizer, of which 30-50% of the nitrogen component is slow release, every 8-10 weeks. Heavier fertilizing should take place in the fall. The cooler your climate the earlier this should happen.

Phosphates

Phosphates help strengthen the root system of your lawn. While many soils will have more than adequate phosphate content, and should not therefore have any phosphorus content added, some soils will require extra nutrition. You should be aware that run-off and leaching of phosphorus used to fertilize lawns can lead to the excessive build-up of algae and weeds in nearby lakes. If you live in an environmentally sensitive area it may be worthwhile carrying out a soil test before selecting a fertilizer. Your local university may help you with this. Phosphates are created from the combination of phosphorus and oxygen, and are immobilized, not forming part of the soil solution. They therefore are less prone to leaching and pose less of a threat to groundwater. Like potash, mature lawns will have a lower requirement for phosphates.

Make your lawn the envy of the neighborhood with a lawn treatment from TruGreen ChemLawn. This powerful and effective treatment will make your lawn greener and healthier, eliminate harmful lawn pests, and destroy unsightly weeds, all in one solution. Act now and get a FREE Lawn Analysis (certain restrictions apply).
Find out more >>

Potash

Potash or Potassium is of great importance to the health and strength of the grass plant. It increases its capacity to withstand the attacks of insects, disease, heat, cold and drought. In order to grow resilient plants, especially in sandy soils in which the grass plant's capacity to retain nutrients in reduced, the addition of potash is important. Like phosphates, a mature should have a reasonable level of nutrient retention and the addition of potash should be less necessary.

Fertilizers

Look on the bag to see the make-up of any fertilizer you buy. There will be three numbers on the label. The first of these numbers indicates the percentage of nitrogen, the second the percentage of phosphates, and the third that of potash.