When to Do the First Lawn Mow of the Season: 11 Considerations

I live in Oregon in the Willamette Valley, where lawns are ripe for mowing beginning in March and April. Frost may still appear, though warm day temperatures and direct sunlight cause the grass blades to grow. I like to cut them before they grow too tall; that way, it’s easier to maintain the lawn for the rest of the year.

Wait too long to mow, and the grass may grow too tall! This is great if you desire a tall lawn, though it’s less than desirable if you want a short one to walk and play on. Grass starts growing quickly once days lengthen and warm in spring. You’ll go from monthly to weekly mowings!

Frosty Weather

Frost is the number one thing to consider before mowing! It’s never a good idea to cut frozen grasses. The tender blades are sensitive to touch; stepping on them will cause them to die before new growth emerges.

Not only are footprints damaging to frozen grass but so is the mowing practice itself. Chopping frozen blades leads to water loss and dehydration. The grass can’t heal itself, and water freely flows out. The lawn will start declining soon after a mid-winter mow. 

If frost is abundant at night but disappears by midday, it’s okay to get your mower out and commence the first cut. Avoid cutting in the early morning or night when the grasses may freeze. It’s also good to wait to mow if hard frosts are forecast for the next two to three days. You want the weather to be cool and mild so the lawn can heal properly; after healing, the established lawn grows frost-tolerant.

Dry Lawn

This issue isn’t common in USDA hardiness zones 1 through 8, where winters have recurring freezes or rainstorms. Growers in zones 9 and above often have dry winters or infrequent rainfall, leading to thirsty, dehydrated lawns when spring arrives. First, ensure the lawn is moist before mowing.

To combat lawn dryness, run sprinklers or hose attachments when the soil surface dries. This is weekly in warm, dry climates during spring and summer, and less often in wet, cool ones. As the seasons change, lawns change, growing less or more depending on sunlight intensity and the temperature in your region. Adapt your watering to match the seasonal growth.

Though less common in zones 1 through 8, lawn dehydration can still occur during uncharacteristically dry winters. Ensure the soil is moist and not soggy while grass is actively growing. Some species are summer dormant, turning brown and dry in summer before sprouting again in fall. They take less water than varieties that grow in summer. 

Wet Lawn

Like dry lawns, wet lawns aren’t suitable for mowing either. I was a landscaper in the Pacific Northwest, and mowing during wet weather was the worst! It caused ruts in soggy areas where the mower wheels drug through the mud. Bare patches form on the ruts, creating an unsightly appearance.

Mowing wet grass also causes buildup on the mower, as the chunks stick to the blades, covers, and chutes. You’ll have to frequently stop and dislodge the wet chunks, turning a one-hour job into a two or three-hour one!

Instead of mowing wet grass, wait for a warm day when the soil dries. A moist lawn is okay to mow, though a soggy one is not. Test the moisture level by stepping on it. If your foot sinks into the ground, it’s likely too wet to mow.

Dead Grass

Though you can mow dead grass patches, it’s best to think about reseeding them in late winter or early spring. That way, when you commence your first mow of the season, you’ll have a full, healthy lawn without bare patches.

To fix dead grass, start by dethatching the area. Dethatching is a simple process that removes dead fluff so fresh blades can grow. Some tools make this job easy. Handheld tools are cheap and last a long time. They have fine twines that catch the dead organic matter and leave growing blades in place. 

Gas and electric tools are more expensive than handheld ones, but they work quicker and with less manual labor. Simply charge or fuel them, then run them over the bare patches. They’ll dislodge and suck up the dead grass and leave living clumps in place.

After dethatching, lightly rake the soil to loosen it. Thickly broadcast cool season grasses on top of the dirt, and water them well. Wait a month or longer after germination before mowing, as young seedlings are weaker than established clumps.

Wildlife Habitat

Lawns aren’t havens for wildlife. Though some critters feed on worms and bugs that come out of a freshly cut one, there isn’t habitat space for them to stay there. You might consider leaving some tall grass around the cut areas for wildlife. 

This is easy to do. Simply mow where you want cut patches, and don’t mow where you want tall ones. Make a design like a cross on a square patch, create small crop circles throughout the yard, or make a winding pathway through a meadow-like landscape. No matter how you design it, the local critters will thank you for thinking of them!

I like to leave tall grass circles around the trees in the yard. Insects are abundant in them, attracting birds and small mammals. I often see squirrels burying nuts in the ground; they scamper across the dead stalks from last year. You may mow the patch in the fall before winter, or consider leaving the dead stalks so insects can overwinter in them.

Old Mowers

Whether you use a new or old mower, a dormant season in the shed can make it look decades old! It’s a good idea to check the sharpness of the blades, the parts for rusty metal, and the inside for dead plant chunks. 

Clean the mower by removing all dead plant material from last year. Wash it down if you must, then let it dry thoroughly. If rust is evident, use a metal sponge or a wire brush to remove it. Then, spray an oil like WD-40 on the metal to keep rust at bay.

The final part to check is the blade. A season or two of mowing can lead to a dull blade that damages the lawn. You may sharpen it yourself, though it’s challenging and requires removing the blade from the mower. I like to take it to a sharpening shop where specialists sharpen it perfectly.  Some big-box home improvement stores also offer sharpening services for cheap.

The ⅓ Rule

When winters are cool and mild, cold-season grasses rapidly grow. It’s best to cut no more than ⅓ of the grass’s height at once. After cutting, the blades need a week to recuperate before you can mow them again.

When you remove more than ⅓ of the height, you may cut the crowns where new growth occurs. Grass recovers well after you cut the tips, though it doesn’t if you cut the crowns. Creeping stolons need some time to emerge from belowground and replace the dead crowns. 

The best lawn height is between two and three inches. This ensures you avoid damaging the grasses’ crowns. It promotes healthy new growth that appears bright green during the growing season. 

Tall Grass

Let’s say you forgot to mow for a while, or you had a particularly warm winter and the grass grew earlier than usual. No matter the case, rapid, unchecked growth can create a prairie in your yard! You may choose to leave some patches tall for wildlife habitat. If you’d like them short, you’ll use the ⅓ rule and slowly lower the height of the stalks. 

Start with a first mow over the tops of the stalks. If the grasses are six inches tall, you’ll remove two inches during the first mow. Sometimes, tall blades miss the mower and stick out over the lawn. Run over these again to make a clean, even cut.

Wait seven days after the first mow, then you can do it again. Remove ⅓ again to lower the height between two and three inches. If it’s still too tall, repeat the process after another seven days until you reach the target height. Then, continue employing a regular mowing routine during the growing season for healthy, green growth.

Mowing Frequency

The best time to mow falls between late winter and early spring, from March through May. Some regions, like Southern California, will require weekly or biweekly mowing as early as December and January. Cold, northern gardens may not need a first mow until late May or early June. 

After the first cut, consistently moist lawns require regular mowing from spring through early fall. Weekly mowing works well during the growing season to maintain a healthy height. Unirrigated lawns need less mowing during summer dormancy and more throughout fall as they grow again. 

You’ll feel the urge to mow as grasses mature rapidly. Frequent cuts encourage more stolons underground and fresh blades aboveground, leading to a dense, healthy patch. Your yard will go from winter dormancy to spring life, inviting your garden visitors to sit and enjoy the lush, fresh growth.

Mulch Mowers

Grasses need fertilizer if they never receive organic inputs. Instead of bagging the yard debris, you can use a mulch plug on your mower to leave the cut debris behind. 

The mower blades chop the grasses, dead leaves, and twigs, turning them into small chunks that decay in the soil. The decayed organic matter feeds the grasses’ roots, which leads to less fertilizer use throughout the year. 

Electric and gas-powered mowers come with mulch plugs that you place on the slot where the bag goes. Remove the bag, put the plug in place, then proceed with your regular mowing routine. Thick patches of debris and tall grasses may require two mowings to ensure proper chopping. 

An economical, eco-friendly mower also works as a mulch mower. The classic mechanical push mower, or reel mower, works with pushing, and that’s it! It consists of a rotary blade that chops grasses and leaves them in place. They’ll wither and fall between growing grasses, where they’ll decay in the soil. 

Fertilizer

Fertilizer is the last thing to consider, and for good reason! Excess nutrients in early spring can cause burning, leading to poor health and performance. Too many and too few nutrients lead to weak grasses prone to infection or infestation. Pests and diseases target the weak growth, further weakening their overall health.