Winter Turf Blankets and Growth Covers

How Do Winter Turf Blankets Work?

Winter turf blankets, also called growth covers or growth blankets, are woven polypropylene fabrics laid over the turf surface to trap solar radiation, ambient heat, and soil moisture against the grass canopy. The result is a microclimate that stays several degrees warmer and more humid than the surrounding environment, even when air temperatures drop well below freezing. Under these conditions, turfgrass stays active at the root level when it would otherwise go dormant, and young grass germinates weeks ahead of uncovered ground.

Turf managers use this effect for two purposes: protecting established turf from winter damage, and accelerating the growth of new or recovering turf. A single FieldSaver® growth cover does both on the same field across one offseason. That dual function comes from how the cover interacts with sunlight, heat, moisture, and winter stressors:

• Sunlight reaches the turf. With up to 90% light transmission, sunlight reaches the canopy and soil, sustaining photosynthesis and root development.
• Heat is retained at soil level. Research shows canopy temperatures average 2°F warmer under the cover, with daytime spikes up to 10°F above ambient air.
• Moisture stays in the ground. The cover reduces wind desiccation and locks in soil moisture, preventing drying that damages dormant or establishing turf.
• Winter stressors are blocked. Turf blankets guard against frost, ice, freezing rain, foot traffic, and animal damage in a single layer.

What Field Managers See Under the Cover

Groundskeepers who have used CoverSports covers for multiple winters report consistent patterns:

• Active root growth continues while uncovered turf goes fully dormant in winter
• Turf density and canopy thickness stay cushioned for safe play on cover removal
• Grass color rates 60% greener than uncovered plots in Penn State research trials
• Spring green-up starts one to three weeks ahead of adjacent uncovered fields

Where Are Growth Covers Used?

FieldSaver® growth covers protect natural-grass surfaces across every major sport:

• Baseball and softball: infields, outfields, and complete diamonds for MLB, college, high school, and Little League programs
• Football and soccer: strategic-zone and complete-surface coverage for NFL, MLS, NCAA, and high school grass fields
• Multi-sport facilities: custom sizes for goal mouths, high-traffic zones, and sideline wear areas
• Sod farms and new seedings: germination acceleration and seedling protection for newly installed turf

Need a different kind of cover? For year-round protection of synthetic or stadium turf during concerts and events, see our synthetic turf protectors. For putting greens and tee boxes, see our golf green and tee box covers. FieldSaver® growth covers protect natural grass at Citizens Bank Park, Lincoln Financial Field, and Subaru Park, plus Little League fields from the Northeast to the Texas Gulf Coast.

Research-Proven Winter Turf Protection

A peer-reviewed study conducted by Dr. G.W. Hamilton Jr. at the Penn State Valentine Turfgrass Research Center measured what happens under a CoverSports polypropylene growth cover across a full winter. The results quantified three distinct performance gains:

• 78% higher growth yield under the cover compared to uncovered control plots, measured as dry-weight clippings at spring green-up
• 60% better spring color rating (4.0 vs. 2.5 on a 5-point scale) when the covers were removed in late March
• 10.5% warmer average January canopy temperature, with daily minimums consistently higher than uncovered turf

The study also found that covered plots restricted the coldest low-temperature excursions, a key factor in preventing direct low-temperature winter kill. The temperature differential alone explains the accelerated spring green-up field managers report across climate zones.

Read the Penn State Study →

Source: Hamilton, G.W. Jr. and Raley, R.B. "Turf Cover Effects on Putting Green Winter Temperature, Spring Green-up and Growth." Penn State Valentine Turfgrass Research Center, 2004.

Case Study: Texas Winter Turf Protection at Pearland Little League

At Pearland Little League in Pearland, Texas, volunteer groundskeeper Greg Loberg maintains the organization's Major Field infield on Seashore Paspalum sod donated by the Houston Astros in 2017. Keeping MLB-grade turf alive through unpredictable Texas winters, months before the active growing season, requires a dedicated winter maintenance program built around one tool: a 60 ft × 60 ft CoverSports growth cover, deployed every winter since 2020.

The cover's value became impossible to ignore during the historic 2021 Texas ice storm. High winds tore part of the cover off the infield — and the turf that stayed covered came through vibrant green while the exposed area went dormant, as visible in the photograph above. Loberg reports he regularly pulls the cover off to mow the field in the middle of winter, a level of active growth that would be unthinkable on uncovered Texas turf in January.

"Had the growth cover not been on the field, it would have been brown, dormant, and taking a beating from day one. The cover gives the grass a cushion to survive that early use."

— Greg Loberg, Volunteer Groundskeeper, Pearland Little League

Read the Pearland Little League Case Study →