By using a mulching mower you can reduce the need for fertilization by as much as 25%.

O.K. You have just installed that new lawn and are wondering when should I fertilize and what type of fertilizer should I use. This page will outline a good program to follow that will keep that lawn green and healthy. You will be amazed at how easy it really is to have a thick lush green lawn with just a few hours of work per year.

Be kind to the environment

When using fertilizer please remember to follow all label directions. Lawns love Nitrogen but excessive use will cause ground water contamination. If we use the right amount of fertilizer we can have dark lush green lawns and safe drinking water. Using excess fertilizer will only cost you more money and end up harming the environment.

Try using a mulching mower and leave your grass clippings on your lawn. Clippings are high in Nitrogen so you will be adding Nitrogen back into your lawn every time you mow, which can reduce the need for fertilization by 25%.

The goal of any fertility program should be to produce good top growth while not at the expense of root growth.
Nutrition (N, P, K)

Nitrogen (N), Phosphorus (P), and Potassium (K) are typically your three main nutrients in lawn fertilizers. The three numbers on a fertilizer bag will represent the percentages of N, P, and K. Sometimes other nutrients will be add in small quantities.

Nitrogen will give your lawn a nice dark green color. It will also promote leaf growth at the expense of root growth. Therefore nitrogen needs to be balanced with Phosphorus and Potassium. When buying fertilizer look for one that has a slow release form of

Nitrogen. Slow release Nitrogen will produce a lawn with good color without excessive leaf growth. It will release nitrogen over a longer period of time resulting in less applications.

Phosphorus is needed for energy transfer in the plant. Generally it is needed in smaller amounts then Nitrogen or Potassium. Newly sodded lawns will need more Phosphorus then established lawns due to the amount of energy the plant will need to establish it's root system.

Potassium is needed so that the plant can withstand disease and insect damage. It promotes good cell wall development in the grass plant.
How much of N, P, K do I need?

A 3-1-2 or 4-1-2 ratio of N-P-K will do well on established lawns. Fertilizers with that ratio include:

  • 12-4-8
  • 15-5-10
  • 16-4-8
  • 21-7-14
  • 20-5-10
The exception to this rule is a newly sodded lawn. You should use a Triple 16 (16-16-16) when you first install your new sod, then switch to a 3-1-2 or 4-1-2 ratio.
When to fertilize

You will probably need to apply fertilizer five times a year. Use the following schedule as a guide.

  • Once in February or March (Early Spring)
  • Once in April or June (Late Spring)
  • Once in August (Summer)
  • Once in September (Early Fall)
  • Once in November (Late Fall)