Summer weather stresses turfgrass, requiring careful timing and specific product selection to prevent damage. High temperatures and potential drought cause grass to enter a stressed state, making it susceptible to fertilizer burn and disease. Understanding when and how to feed your lawn is paramount to maintaining its health. The correct summer approach depends entirely on the species of grass you are cultivating.
Identifying Your Grass Type
Successful summer lawn care depends on identifying your turf as either warm-season or cool-season grass. Warm-season grasses (Bermuda, Zoysia, St. Augustine) thrive in temperatures between 80 and 95 degrees Fahrenheit, making summer their peak growth period. Cool-season grasses (Kentucky Bluegrass, Tall Fescue, Perennial Ryegrass) prefer cooler temperatures (60 to 75 degrees Fahrenheit) and slow their growth significantly during the heat of July and August. Identifying the grass type is the primary factor for setting your summer fertilization schedule.
Summer Fertilization Schedules for Warm-Season Grasses
Summer is the primary active growing season for warm-season turfgrasses, making this the ideal time to provide nutrients. The first feeding window occurs in late spring or early summer (mid-May to early June), once the grass has fully emerged from dormancy and soil temperatures reach 65 degrees Fahrenheit. This application supports the initial flush of vigorous summer growth.
A second application can be beneficial in mid-to-late summer (July and August) to sustain growth and vibrant color. Apply fertilizer when temperatures are not at their daily peak, ideally in the early morning or late evening when the grass is dry and the air is cooler. This timing minimizes the risk of scorching the blades. For best results, applications should be spaced approximately six to eight weeks apart during the active growth period.
Why Cool-Season Grasses Must Be Handled Differently
Cool-season grasses naturally enter a state of stress or semi-dormancy when summer temperatures consistently climb above 80 degrees Fahrenheit. During this time, the plant focuses its energy on survival, and its ability to absorb nutrients is significantly reduced. Applying heavy nitrogen fertilizer during peak summer (July and August) forces the grass into an unsustainable growth spurt.
This forced growth weakens the plant’s root system, making it vulnerable to heat stress, drought, and disease. Experts advise against heavy fertilization during mid-summer, reserving major feeding for the cooler conditions of spring and fall. If the lawn appears weak, a very light application of a specialized, low-nitrogen product may be considered, but heavy nitrogen applications must be strictly avoided.
Essential Preparation and Application Methodology
The method of application is almost as important as the timing, especially when dealing with summer heat. Before applying, mow the lawn to its normal height so granules can reach the soil surface easily. Use a slow-release nitrogen fertilizer, often labeled as controlled-release, as this provides a steady supply of nutrients over several weeks. This greatly reduces the risk of a sudden growth surge or chemical burn compared to quick-release formulas.
Immediately following the application of granular fertilizer, the lawn must be watered deeply. This washes the product off the grass blades and carries the nutrients into the root zone. This irrigation activates the slow-release mechanism and prevents fertilizer salts from drawing moisture out of the blades, which causes summer lawn burn. Avoid fertilizing a lawn that is already visibly stressed, wilted, or suffering from drought, as this can cause further damage.