A healthy lawn is a feast for the eyes. It is thick and luxurious and has luscious colour. No empty spaces offer a home for weeds. The blades are strong, the roots are dense and far spreading. The key to such health and beauty? Good nutrition on a regular schedule.
Grass grows constantly, which means it requires a steady diet of nutrients. Even though many nutrients occur naturally in the soil, the soil is unable to supply them as fast as or in quantities that the plants call for them. For that reason good nutrition for a lawn is the result of a balanced fertilizer program that supplies the right nutrients in the correct amounts at the best time for the lawn.
The ideal fertilizer program is one that provides uniform growth throughout the season. Most fertilizers have the details figured out for you on the label.

Lawns will survive without fertilizer. However, the less fertilizer the lawn receives, the more its quality deteriorates. As a lawn runs out of nutrients, the first thing to go is colour. The luscious green turns pale. Over time,  the lawn thins. Thin spots provide space for weeds to move in. Deficient grass is not vigorous, and if diseases and insects attack, it cannot outgrow damage.
Although it is true that the more fertilizer a lawn receives the better it looks, over fertilizing can be bad too. Over fertilizing stimulates leaf growth at the expense of the roots. The root system will be thin and shallow, so the lawn cannot stand up to heat or drought. The succulent shoots are easy prey for diseases and insects. In addition, over fertilizing promotes thatch.

As a general rule, lawns in northern regions are called cool season lawns, should receive three to five feedings per year.  The number of feedings listed here provide for a lawn of the highest quality.
It is best to split the total amount of fertilizer required into three to five applications. The timing of the feedings and amount you apply with each one depends on the type of grass species. In general it is best to fertilize when the lawn is actively growing, when fertilizer will enhance root growth and food storage.

Cool season grasses put on the most growth during the spring and the fall. During the summer, growth slows as the grass waits out the heat. When temperatures cool in the fall, the lawn resumes growth, but now it is storing food for the winter ahead.
For cool season grasses, the biggest feeding should be in the late summer and fall. Provide two meals, one in late summer to thicken the stand and provide healthy roots. A second feeding,  a month or so later winterizes the lawn to build food reserves for the dormant period ahead.  Spring calls for small snacks in early and late spring. The time to begin fertilizing coincides with the first mowing. You know the grass is growing then.

Liquid or Dry:
Fertilizer can be applied to a lawn in liquid or dry form. People often ask which is best. The truth is, lawns don't care. Both contain the same materials and both provide satisfactory results, although liquids are quick-release fertilizers and must be applied more frequently.
The question is more a matter of convenience and skill. It takes more skill to uniformly apply liquid fertilizer at the right rate. Most homeowners generally find dry material easier to handle, especially if they have a good spreader that accurately and uniformly distributes the fertilizer.
Almost everyone knows firsthand the embarrassment of a yellow striped lawn. You can't hide it from the neighbours and it takes weeks to go away. After spending the time, effort and money on fertilizing, you may feel it was all a waste.*


* Reprinted from Scott's Lawns - Your Quick Guide to a Beautiful Yard - by Nick Christians with Ashton Ritchie - Meredith Books, Des Moines, Iowa