When should I fertilize my lawn and garden?

Fall’s near-freezing temperatures have arrived. Fertilizer can be applied to lawns and gardens during fall before frost and freeze.

Importance of soil testing

The most accurate way to determine what type of fertilizer your soil needs is by completing a soil test. A soil test will tell you all of the nutrients that your soil needs for productive growing. While soil testing can be completed in the fall or spring, don’t fertilize in the spring unless the soil test indicates that your lawn needs phosphorus, potassium or lime, according to experts. Soil only needs to be tested every two or three years.

Understanding fertilizer

Once you’ve received the results from your soil test, you’ll know which nutrients your soil needs to improve. Cornell University Extension says that light fertilizer application is necessary each year to replace nutrients used by vegetables, flowers and other plants the previous year and through water leaching.

Complete fertilizer contains the macronutrients nitrogen, phosphorus and potassium. You’ll notice on a bag of fertilizer three numbers, separated by dashes. Each of these numbers indicates the percentage of each element. Nitrogen is needed each season for garden plants, as are phosphorus and potassium. For lawns, nitrogen promotes the green color and lawn denseness.

Soil tests give fertilizer ratio recommendations.

Ohio State University Extension explains that lime is necessary for increasing soil’s pH level. In Ohio, home lawns should have a pH between 6.0 and 7.0, indicating that the soil is slightly acidic. Most plants will thrive with a soil pH of 6.8. Apply lime any time during the year, except when grass is frost-covered or wilted.

When should I apply fertilizer?

There are benefits to fall lawn fertilizer application, Ohio State University Extension says. Disease and weed problems are typically not as prevalent as during the summer, and heat and drought tolerance have improved by then, too. Plants may be healthier in the spring and summer after a fall application.

Don’t fertilize when the ground is frozen and don’t apply fertilizer to dormant or severely drought-stressed turf.

OSU Extension lists recommended lawn fertilizer application times here, based on fertilizer grades.

For gardens, fertilizer is applied before planting. The fertilizer is tilled or spaded into the soil. OSU Extension has further recommendations about garden fertilizing here.

Reminders

Don’t over-fertilize. Keeping in mind Lake Erie’s toxic algae issue. Plants don’t use excess fertilizer, so it ends up washing into the watershed, Pam Bennett, Ohio State University horticulture educator and director in Clark County and statewide Master Gardeners Volunteer Program coordinator says.

More about lawn and garden soil:

• How do I know if the soil in my garden is healthy?
• How to test your garden’s soil
• How to prepare garden soil for spring planting