What is the General Rule for Summer Mowing Frequency?
Generally, you should mow your lawn once per week during the summer, or every 5–7 days. The key principle is to mow only when the grass has grown about one-third above its recommended cutting height. This simple schedule promotes healthy, dense turf and helps the grass withstand summer stress.
This weekly rhythm is a reliable starting point for most lawns in temperate climates. However, the exact timing depends on how fast your grass is actively growing, which is influenced by rainfall, temperature, and your specific grass type.
The One-Third Rule for Mowing Grass
The most important rule for mowing any lawn, at any time of year, is the one-third rule: never remove more than one-third of the grass blade’s total height in a single mowing session. Cutting off more than this shocks the grass, stresses the root system, and can lead to browning and increased vulnerability to disease.
For example, if your cool-season grass like Tall Fescue is best maintained at a 3-inch height, you should mow when it reaches about 4 inches tall. Removing 1 inch (one-third of the 3-inch height) brings it back to the ideal 3 inches.
How Do Heat and Drought Affect Your Mowing Schedule?
Summer weather is not uniform. During periods of extreme heat, drought, or when the grass is under stress and growth slows, you should reduce the mowing frequency and raise the mower blade to avoid scalping the lawn.
Why Mow Less Often During a Heatwave or Drought?
When temperatures soar and water is scarce, most grasses enter a semi-dormant state to conserve energy and moisture. Their growth rate slows dramatically. Forcing a weekly mowing schedule during this time can be counterproductive. You may be cutting off very little new growth, but the act of mowing itself—especially with heavy equipment—can compact dry soil and damage stressed grass crowns.
Signs your lawn is heat-stressed include a blue-gray color, footprints that remain visible after walking on the grass, and soil that is dry and cracked. During these periods, it’s better to mow every 10-14 days, or only when the grass has actually grown enough to justify a cut according to the one-third rule.
Recommended Mower Blade Height Adjustment
When heat and drought are severe, raising your mower blade is a critical adjustment. Taller grass blades shade the soil, which helps retain precious moisture, keeps the root zone cooler, and protects the grass crowns from direct, scorching sunlight.
As a general guideline, you can raise your mower blade by 0.5 to 1 inch above the normal recommended height for your grass type during extended hot, dry spells. For instance, if you normally mow your Bermuda grass at 2 inches, consider raising the deck to 2.5 or 3 inches until conditions improve.
Does Your Grass Type Change the Mowing Advice?
Yes, absolutely. The ideal mowing height and summer growth rate depend heavily on whether you have a warm-season grass or a cool-season grass.
Warm-Season vs. Cool-Season Grass Growth in Summer
- Warm-Season Grasses (e.g., Bermuda, Zoysia, St. Augustine, Buffalo): These grasses thrive in the heat. Their peak growing season is summer. They will grow vigorously and may require mowing more frequently than once a week during periods of adequate rain and fertilization. They are generally more drought-tolerant but still benefit from higher mowing heights during severe stress.
- Cool-Season Grasses (e.g., Tall Fescue, Perennial Ryegrass, Kentucky Bluegrass): These grasses prefer cooler temperatures and grow most actively in spring and fall. In summer, their growth slows significantly, especially in hot climates. They are more susceptible to heat and drought stress. Mowing frequency often decreases to every 10-14 days in summer, and maintaining a higher cut is essential for survival.
Ideal Summer Mowing Heights for Common Grasses
| Grass Type | Normal Summer Mowing Height | Height During Heat/Drought Stress |
|---|---|---|
| Bermuda Grass | 1.5 – 2.5 inches | 2 – 3 inches |
| Zoysia Grass | 1.5 – 2.5 inches | 2 – 3 inches |
| St. Augustine Grass | 2.5 – 4 inches | 3.5 – 4.5 inches |
| Tall Fescue | 3 – 4 inches | 3.5 – 4.5 inches |
| Perennial Ryegrass | 2.5 – 3.5 inches | 3 – 4 inches |
Step-by-Step: How to Determine When to Mow This Week
Instead of blindly following a calendar, use this simple method to decide if it’s time to mow.
How to Visually Check If Your Lawn Needs Mowing
- Know Your Target Height: First, identify your grass type and its ideal mowing height (refer to the table above).
- Measure the Grass: Use a ruler or tape measure to check the height of a few grass blades in different parts of the lawn.
- Apply the One-Third Rule: Calculate one-third of your target height. If the grass is taller than your target height plus that one-third amount, it’s time to mow.
- Consider the Conditions: Is the grass actively growing (green, moist soil)? Or is it stressed (dry, blue-gray)? Adjust your decision accordingly.
What to Do If You Miss a Mowing and the Grass is Very Tall
If you’ve been away or the weather prevented mowing and the grass is now much taller than your target height, do not cut it all at once. Removing more than one-third of the blade height will severely scalp and stress the lawn.
Instead, follow the “double-cut” method:
- First Cut: Set your mower to its highest setting and mow the entire lawn, removing only about one-third of the excess height.
- Wait a Few Days: Allow the grass 3-5 days to recover from this initial cut.
- Second Cut: Now, lower the mower to your normal desired height and mow again to bring the grass to its proper level.
Frequently Asked Questions
Can I mow my lawn in the summer when it’s very hot outside?
Yes, but with caution. Avoid mowing during the hottest part of the day (typically 10 AM to 4 PM) as this stresses both you and the grass. Mow in the early morning or late evening. If the grass is visibly heat-stressed (blue-gray color, footprints remain), it’s better to delay mowing and raise your blade height when you do cut.
Should I water my lawn right after mowing in the summer?
It’s generally better to water your lawn before mowing, ideally the day before. This ensures the grass is hydrated and less prone to stress from the cutting process. Watering immediately after mowing, especially in the heat of the day, can promote fungal diseases. If you must water after, do it in the late evening to allow the grass blades to dry overnight.
What is “scalping” and why is it bad for my summer lawn?
Scalping is removing too much of the grass blade at once, often by setting the mower too low or cutting grass that is excessively tall. In summer, scalping is particularly harmful because it removes the grass’s natural shade for the soil and roots, exposing them to direct sun and heat. This leads to moisture loss, crown damage, and can kill the grass.
Does mulching grass clippings help my lawn in the summer?
Yes, mulching grass clippings (using a mulching mower or leaving clippings from a standard mower) is highly beneficial. The clippings decompose quickly, returning valuable nitrogen and moisture to the soil. This natural fertilization reduces the need for summer feeding and helps the soil retain moisture, which is crucial during hot, dry periods.
