Fertilizing replenishes soil nutrients to support healthy plant growth. Success depends entirely on proper timing, which is challenging in a state as vast and climatically diverse as Texas. Applying fertilizer at the wrong time is inefficient and can harm plants, encourage weeds, or lead to nutrient runoff that pollutes waterways. A strategic schedule ensures nutrients are available precisely when plants are actively growing and can absorb them.
Understanding Texas Climate Zones for Timing
The immense size of Texas means a single calendar date cannot define the start or end of the growing season. The most accurate trigger for fertilization is soil temperature, not a fixed date. Warm-season turfgrasses, which dominate most of the state, begin active growth when the soil temperature consistently reaches 65°F at a four-inch depth.
This temperature benchmark varies significantly by region. The 65°F threshold can be met in South Texas and the Gulf Coast as early as late February or early March. Central Texas typically hits this mark later in March or early April, while North Texas areas may not see consistent 65°F soil temperatures until mid-April. This geographical difference dictates that fertilization schedules must be staggered from south to north.
Fertilization Schedule for Warm-Season Grasses
Most Texas lawns use warm-season varieties, such as St. Augustine, Bermuda, and Zoysia grass, which grow actively from spring through early fall. The first fertilizer application should occur after the grass has fully broken dormancy and required mowing two or three times. This confirms the grass is actively growing and ready to utilize the nutrients, correlating with the 65°F soil temperature trigger.
For South Texas, this initial feeding may occur around early March, but in North Texas, waiting until mid-April is safer to avoid feeding early-season weeds. This first application should use a balanced, slow-release fertilizer that encourages steady growth. Ratios like 3-1-2 or 4-1-2 are common recommendations for this spring boost.
Warm-season grasses benefit from two to four applications throughout the active growing season to maintain vigor. Subsequent feedings should be spaced approximately six to eight weeks apart, continuing through the summer. Fertilizing during peak summer heat requires caution, as high-nitrogen products can stress the turf and increase the risk of disease or burn. A light application of a slow-release nitrogen fertilizer in late spring or early summer can help the grass withstand heat stress.
Late-Season Applications and Dormancy Preparation
The final fertilizer application focuses on strengthening roots and preparing the turf for winter dormancy, not stimulating new growth. This late-season feeding should occur when the grass is still green but its top growth has slowed, typically between early September and mid-October. Timing is crucial to ensure nutrients are absorbed before the first hard frost, which signals true dormancy.
For this application, switch to a formula with a higher percentage of potassium and lower nitrogen content, such as a 3-1-5 ratio. Potassium enhances the turf’s cold tolerance and aids in root development, helping the grass store energy reserves for winter and promoting strong spring recovery. Applying high levels of nitrogen too late in the fall can promote new growth highly susceptible to winterkill and frost damage.
Cool-Season Grasses
This fall schedule differs for cool-season grasses like Tall Fescue, sometimes used in shaded areas of North Texas. Cool-season grasses grow most actively in cooler months, making fall the most important time for fertilization. Fescue lawns benefit from a feeding in September and another application in November, aligning with their peak growth period.
Timing for Trees, Shrubs, and Landscape Plants
Woody ornamentals, including established trees and shrubs, require less frequent fertilization than turfgrass. The most beneficial times to fertilize these plants are in late winter or early spring before new growth begins, and again in late fall after growth has ceased. This timing allows the plants to take up and store nutrients to fuel the next season’s growth.
Applying fertilizer in late winter ensures nutrients are in the root zone just as the plant emerges from dormancy. For heavy clay soils common in Texas, applying fertilizer in mid-winter allows more time for nutrients to penetrate the dense soil structure. The second primary window is late fall, which supports root development throughout the winter and helps the plant recover from summer stress.
It is recommended to avoid fertilizing trees and shrubs during the intense heat of mid-summer, as high temperatures and drought can limit nutrient absorption and increase stress.
Young Plants and Flowers
Young, newly planted trees and shrubs may require more frequent, light feedings—two or three times a year—to establish robust root systems quickly. Annual and perennial flower beds benefit from feeding at the time of planting and then intermittently throughout their blooming season, as they expend significant energy producing flowers.