Kentucky Bluegrass can survive drought conditions for 4–6 weeks before it begins to die. It’s important to note that during a drought, Kentucky Bluegrass enters dormancy, where it turns brown and may appear dead. However, it is still living. When water returns following drought, Kentucky Bluegrass will green up again in 2–3 weeks.
When compared to other cool-season grasses, Kentucky Bluegrass is not the most drought-tolerant choice for your lawn. Fescues typically perform better in drought than Kentucky Bluegrass. Tall Fescue is the top choice for a drought-tolerant lawn in cool climates.
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Does Kentucky Bluegrass Struggle in Drought Conditions?
Kentucky Bluegrass thrives on water and is quick to go dormant when drought strikes. After 14 days without water, Kentucky Bluegrass will begin to turn brown and settle into dormancy. This dormancy period allows the grass to ride out drought conditions for up to 6 weeks before it begins to die.
Does Kentucky Bluegrass Need a Lot of Water?
In cool conditions, Kentucky Bluegrass thrives on 1 inch (2.5 cm) of water per week. However, as temperatures rise above 80℉ (27℃), Bluegrass irrigation needs jump to 2–2.5 inches of water per week. This makes it a very thirsty grass.
- In temperatures below 80℉ (27℃), Kentucky Bluegrass requires 1 inch of water (2.5 cm) per week.
- In temperatures above, Kentucky Bluegrass water needs increase to 2–2.5 inches (5–6.5 cm) per week.
- If Bluegrass does not receive adequate water in high temperatures, it will enter summer dormancy.
Although Bluegrass can make do with less water in summer, this will lead to your lawn entering summer dormancy. Growth will slow as the lawn turns brown. This is the natural Bluegrass reaction to insufficient summer water.
How Long Can Kentucky Bluegrass Go Without Water?
6–8 weeks is typically the longest period of time Kentucky Bluegrass can go without water before grass plants begin to die. Although some Bluegrass plants can survive beyond 8 weeks without water, this won’t be true for the entire lawn.
- Kentucky Bluegrass can survive 6–8 weeks of extended drought before it begins to die.
- Extended dormancy (longer than 6 weeks) will kill some Bluegrass plants and cause the survivors to struggle when water returns.
- Bluegrass that enters dormancy may require 2–3 weeks to exit dormancy once water returns.
When a long drought ends, the Bluegrass that survives has a lot of ground to cover. It will expend most of its energy coming back from dormancy, recovering its green color, and trying to cover dead patches. If allowed to enter dormancy in summer, Kentucky Bluegrass can become invaded with weeds.
Does Kentucky Bluegrass Go Dormant During Drought?
Kentucky Bluegrass exposed to drought and heat will enter summer dormancy. This means that at the height of summer, your Bluegrass lawn may be almost entirely brown if it doesn’t receive enough water.
- Kentucky Bluegrass will begin to go dormant after 1–2 weeks of drought.
- Summer dormancy is common among underwatered or drought-stricken Bluegrass lawns.
Dormancy is the defense mechanism of the Bluegrass. It stops growing, loses its green color, and shuts down to try and ride out the drought.
Kentucky Bluegrass Drought Tolerance vs. Competitor Grasses
Kentucky Bluegrass is a cool-season grass, adapted to growing in the northern half of the United States and all regions of Canada. For purposes of comparison, we will look at Kentucky Bluegrass versus other common cool-season turf grasses. The grasses we’ll discuss are:
- Kentucky Bluegrass: shallow-rooted and prone to entering dormancy during drought.
- Fescue: Known for deep roots, especially in the Tall Fescue variety.
- Ryegrass: Bunch-forming grass that may struggle to recover from drought.
Let’s take a closer look to see how Kentucky Bluegrass stacks up against the others. This will help you make the right choice for your lawn.
Is Fescue or Kentucky Bluegrass Better for Drought Conditions?
Fescue thrives in summer with about half the water required to keep Kentucky Bluegrass green. If you live in a region with drought or water limits, Fescue is a better choice for a green summer lawn than Kentucky Bluegrass.
The reason for Fescue’s drought survival lies in its roots. Tall Fescue roots delve down 24 inches (60 cm) to pull in water in nutrients. In comparison, Kentucky Bluegrass has shallow roots, only a few inches deep. When summer heatwaves hit, the Kentucky Bluegrass root zone dries out quickly.
- Fescue will remain green in summer with 1–1.25 inches of water—half of what Kentucky Bluegrass requires.
- Because of its deep roots, Fescue will remain green through brief droughts.
- Because of its shallow roots, Kentucky Bluegrass enters drought quickly.
- Tall Fescue recovers very well from drought, returning to a lush lawn in 3–4 weeks.
- Kentucky Bluegrass can recover from drought but needs more than 4 weeks of adequate water for a complete recovery.
Tall Fescue is the best choice among cool-season grasses when it comes to water conservation, drought hardiness, and drought recovery. It beats Bluegrass in this category, but you can get the benefits of both by mixing the two grass types.
Is Perennial Ryegrass Better at Surviving Drought than Kentucky Bluegrass?
Ryegrass survives drought worse than Kentucky Bluegrass. Ryegrass enters dormancy quickly in drought and struggles to recover. Perennial Ryegrass lawns often come back from drought patchy and irregular. This is because Ryegrass is a bunch-forming grass. Kentucky Bluegrass may take a while to recover from drought, but it spreads well and heals damaged areas.
- Ryegrass is less thirsty than Bluegrass. It requires 1.5 inches of water per week in summer.
- Ryegrass enters dormancy in 1–2 weeks of drought, about the same speed as Bluegrass.
- Ryegrass struggles to recover from drought. It often comes back patchy, with dead areas.
- Kentucky Bluegrass recovers from drought better than Ryegrass. Once it greens up again, Bluegrass will spread to repair damaged areas.
If your choice is between Bluegrass and Perennial Ryegrass for a drought-resistant lawn, go with Kentucky Bluegrass. You’ll get a fuller, more even lawn that can recover from drought if given time and water.
What is the Most Drought-Tolerant Kentucky Bluegrass Cultivar?
Some varieties of Bluegrass have been developed to increase drought tolerance and allow your lawn to survive tough summer conditions. Some of the most drought-resistant Kentucky Bluegrass cultivars are:
When purchasing Bluegrass seed or sod, ask about the cultivars available. You’ll have better luck weathering long days of drought if your Bluegrass variety has been bred to hold up to the task.
Can Kentucky Bluegrass Survive Drought?
Kentucky Bluegrass can survive a drought of up to 8 weeks. However, your lawn will begin to enter dormancy after 2 weeks without water. Once drought-stricken Bluegrass has gone dormant, it will take 2–3 weeks of water for it to green up and begin actively growing again. It is not a very drought-tolerant grass.
In cool regions where Kentucky Bluegrass can be grown, Tall Fescue is a much more drought-tolerant option for your lawn. Thanks to its deep roots, Tall Fescue can survive short droughts without turning brown, and it recovers quickly from drought conditions.