A Simple Lawn Fertilizing Schedule for Northern Illinois

Fertilizer is where homeowners either overthink it or overdo it. The truth is that a cool season lawn in Lake County has a fairly simple appetite, and four well timed feedings will beat eight random ones every time.

The four application year

Late spring, roughly mid May

Wait until the lawn has greened up on its own and you have mowed a few times. Feeding too early in April pushes soft top growth at the expense of roots, right before the plant needs those roots for summer. A balanced feeding here supports the spring growth flush.

Early summer, roughly late June

A lighter application to carry the lawn into the heat. Use a slow release product so you are not dumping a surge of nitrogen right as temperatures climb.

Early fall, late August into September

This is the recovery feeding. The lawn is coming out of summer stress into the best growing conditions of the year, and this application drives the thickening that happens every autumn. If you are overseeding, use a starter fertilizer here instead.

Late fall, late October into November

The most valuable application of the year and the one most people skip. Apply after top growth has essentially stopped but while the ground is still unfrozen. The grass is no longer pushing blades, so it banks that nitrogen in the roots and crown, and you see it come back as a fast, deep green spring greenup weeks before your neighbors.

How much is enough

Roughly three to four pounds of actual nitrogen per thousand square feet per year, spread across those four feedings, suits most Lake County lawns. The first number on a fertilizer bag is the nitrogen percentage, so a 24 percent nitrogen product delivers about a pound of nitrogen for every four pounds of product.

• Choose slow release nitrogen for steadier growth and far less burn risk.
• Always sweep granules off driveways and sidewalks back onto the lawn, because what washes into a storm drain ends up in our waterways.
• Water in after applying unless the label says otherwise.
• Skip phosphorus unless a soil test or new seeding calls for it. Illinois restricts phosphorus lawn fertilizer for good reason.

When not to fertilize

Do not feed a lawn that has gone dormant and brown in a July drought. You are asking a plant with no water to produce growth it cannot sustain, and you risk burning it outright. Wait for rain and recovery.

A soil test every few years takes the guesswork out entirely and tells you what your yard is actually short of. If you would rather have the whole program handled on schedule, call or text 224-634-0673 or 224-200-8363.

Ruiz Landscaping serves Vernon Hills, Libertyville, Mundelein, Buffalo Grove, Lincolnshire, Long Grove and the rest of Vernon Hills's surrounding North Shore and Lake County communities.