Turfgrass Water Usage

June 19, 2012Lawn Care, Sprinkler SystemsBy Green Guys

This post is a more technical but important to understand turfgrass water usage.

This information is based on the research of J. B. Beard in 1973. It dealt with the total amount of water used for growth plus that lost by transpiration and evaporation from plant and soil surfaces. May or may not be related to drought resistance.

Below is a chart that indicated the Turfgrass Evapotranspiration (ET) Classification

RelativeET Ranking	mm day-1	Example
Very low	< 4.0
Low	4.0-4.9	Kentucky bluegrass, buffalograss
Medium-low	5.0-5.9
Medium	6.0-6.9
Medium-high	7.0-7.9
High	8.0-8.9
Very high	>9.0	Tall fescue

Turfgrass Species (Common Scientific Name)	ET* Rates	(mm day-1)
Tall Fescue (Festuca arundinacea)	7-13	2.0-3.8 inches/week
Perennial Ryegrass (Lolium perenne)	7-11
St. Augustinegrass (Stenotaphrum secundatum)	6-11
Seashore Paspalum (Paspalum vaginatum)	6-8
Bahiagrass (Paspalum notatum)	6-8
Kikuyugrass (Pennisetum clandestinum)	6-9
Creeping Bentgrass (Agrostis Palustris)	6-10
Centipedegrass (Eremochloa ophiuroides)	5-9
Bermudagrass (Cynodon spp.)	4-9
Zoysiagrass (Zoysia spp.)	5-8
Kentucky Bluegrass (Poa pratensis)	4-7
Buffalograss (Buchloe dactyloides)	3-6	0.8-2.0 inches/week

* ET rates when water is non-limiting; Potential Evapotranspiration

In other words, which turf can survive without water?

BEST: buffalograss, blue grama, bromegrass, wheatgrasses, bermudagrass can survive without ANY supplemental irrigation.

FAIR: Kentucky bluegrass, fine fescues, bentgrass and zoysiagrass can become dormant and survive for many (3-6) months without irrigation; some thinning will occur.

POOR: perennial ryegrass and tall fescue may survive 2-4 months without ANY irrigation, but will be severely thinned.

VERY POOR: annual bluegrass

Which factors affect drought survival?