How long it takes for grass to dry depends on several factors, including the type of grass, weather conditions, season, and whether the grass has been cut recently. In general, grass can take anywhere from 2-48 hours to dry completely after getting wet from rain, watering, or morning dew. The speed at which grass dries impacts everything from being able to mow the lawn to kids being able to play outside. Understanding the grass drying process and the variables that affect it can help you plan your lawn care and outdoor activities appropriately.
What affects how quickly grass dries?
There are several key factors that determine how quickly grass will dry out after getting wet:
Type of grass
Different grass species have differing water retention abilities. For example, Kentucky bluegrass is quite good at retaining moisture, meaning it will typically take longer to dry out than a grass like Bermuda grass. The blade width also affects drying time, with wider bladed grasses like St. Augustine grass holding more water and drying more slowly than narrow blade types like fine fescues.
Weather conditions
The weather has a major impact on drying time. On a warm, breezy, sunny day, grass can dry in as little as 2-3 hours. But during cool, cloudy, humid conditions drying can take 24 hours or longer. Wind and sunshine help accelerate evaporation of the water from the grass blades. Heat causes the grass plants to transpire more rapidly as well.
Season
During the hot, dry summer months, grass dries quickest. In the winter when temperatures are coolest and humidity is higher, drying time increases. Spring and fall present variable conditions, depending on the weather.
Grass height
Longer grass blades hold more moisture. So recently cut grass will dry faster than grass that hasn’t been mowed in several weeks. Turf grass cut to a height of 2-3 inches dries most efficiently.
Shade vs. sun
Grass in full sun dries out much more quickly than grass growing in heavily shaded areas. The lack of direct sunlight and warmth slows evaporation. Grass under trees or on the shady side of buildings will take longer to dry.
Slope of ground
Grass on a steep hillside or grade will drain faster and dry quicker than grass on level ground or in a depression. The water literally runs off sloped areas more quickly.
Soil type
Soil acts like a sponge, absorbing and retaining water. Grass growing in sandy soils drains faster and dries quicker than grass in heavy, clay-based soils that hold more water. Adding organic materials like compost to soil improves drainage.
Recent watering or rain
The more saturated the grass blades are, the longer the drying time. A brief, light rain shower will evaporate faster than a heavy downpour or lengthy irrigation cycle. The initial moisture content when the drying process starts has a major impact.
Humidity
The amount of moisture in the air impacts the rate of evaporation from grass blades. Higher relative humidity in the air slows drying time compared to very dry air. This partly explains grass drying slower in certain seasons.
How long does it take various types of grass to dry?
Here are some estimates for drying times of common grass types under typical conditions:
| Grass Type | Drying Time |
|---|---|
| Bermuda grass | 2-3 hours |
| Zoysia grass | 3-5 hours |
| St. Augustine grass | 4-6 hours |
| Centipede grass | 4-7 hours |
| Kentucky bluegrass | 6-10 hours |
| Tall fescue | 8-12 hours |
| Fine fescue | 8-12 hours |
| Perennial ryegrass | 8-12 hours |
These drying times assume moderate temperatures, low humidity, and sunny conditions. Drying will be slower during cool, cloudy, damp weather and faster during very hot, arid, breezy conditions.
Bermuda and zoysia grasses dry fastest, while the fescue and ryegrass species are slower to dry out. St. Augustine dries relatively quickly due to its wide blades dispersing water when breezes blow.
When is grass dry enough to mow after rain or watering?
In terms of grass drying enough to be able to mow, most turf experts recommend waiting until the grass is dry to the touch. Walk across a section of grass and touch the blades…if water comes off on your fingers or shoes, it’s still too wet to mow.
As a general guideline, wait the following times before mowing after rain or irrigation:
- Bermuda grass: 3 hours
- Zoysia grass: 4 hours
- St. Augustine grass: 5 hours
- Centipede grass: 6 hours
- Kentucky bluegrass: 8 hours
- Tall fescue: 10 hours
- Fine fescue and ryegrass: 10-12 hours
These times assume a moderate rainfall or sprinkler running time of 30 minutes to 1 hour. Less watering would shorten the time needed. More intense rain or longer irrigation would lengthen the drying period before mowing can commence. Waiting until grass is dry to mow avoids tracking wet clippings on sidewalks and roads. It also prevents rusting and dulling mower blades.
When is grass dry enough for pets or children to use?
Pet owners often ask how long after rain or watering they need to wait before letting their dogs out onto the lawn. Here are some general guidelines on when grass is typically dry enough for pets after getting wet:
- Bermuda grass: 4 hours
- Zoysia grass: 5 hours
- St. Augustine grass: 6 hours
- Centipede grass: 7 hours
- Kentucky bluegrass: 10 hours
- Tall fescue: 12 hours
- Fine fescue and ryegrass: 12-24 hours if heavy rain
Allow even more time if the grass is being used for activities like soccer or tag games to minimize damage. Grass needs extra time to adequately dry before play or high traffic occur.
For grass to be dry enough for children to play after rain, add 2-3 extra hours to the times for pets above. Supervise young kids at first to ensure the lawn is not getting torn up or damaged by play that’s too soon after a soaking.
When is grass dry enough after dew to mow or use?
Grass dew typically dries much faster than rain or irrigation. Here are some guidelines for dry times after dew:
- Bermuda grass: 1 hour
- Zoysia grass: 1-2 hours
- St. Augustine grass: 2 hours
- Centipede grass: 2-3 hours
- Kentucky bluegrass: 3-4 hours
- Tall fescue: 4-6 hours
- Fine fescue and ryegrass: 6 hours
Morning dew on grass evaporates rapidly once the sun comes up and the air warms. But shaded and low-lying areas may still be quite damp. Walk across the lawn to check for wetness before mowing, playing or other activities.
Tips for drying out a lawn
Here are some useful tips for speeding up the drying process if you need your lawn to dry faster:
- Mow with sharp blades set at the highest recommended height for the grass variety. Longer grass exposes more surface area to sun and wind.
- Thin grass in shaded areas to improve air circulation and light penetration.
- Remove thatch buildup by raking, dethatching or aerating. Thatch holds moisture.
- Avoid over-watering which saturates the soil and takes longer to dry.
- Use fans or blowers to create air movement across the lawn.
- Apply calcium chloride or absorbing compounds to pull moisture out of the grass.
- Minimize foot traffic and equipment use until grass has dried.
- Use a lawn dryer designed for golf courses.
Cutting the grass a little longer provides more surface area for evaporation while creating a healthier growing environment for the turf. Raking thatch opens the lower canopy and soil surface for faster moisture evaporation. Oscillating fans are an easy way to speed drying without labor. Absorbent products like moisture remover granules pull water out and shorten dry down times substantially.
Conclusion
How quickly grass dries is dependent on many interacting factors. Grass type, weather conditions, season, sun exposure, soil drainage, and blade length all play a role. Bermuda and zoysia grasses dry fastest under optimal conditions, often in 2-3 hours. The fescue species are slower. Dew typically dries in 1-6 hours based on grass variety. For rain or irrigation, allow 3-12 hours of dry time before mowing or heavy use. There are various management practices that can hasten drying if the grass needs to be usable faster. Understanding the drying process enables proper lawn care scheduling and use.
