Some local water departments forbid night watering to prevent waste from sprinklers left on all night.

A local university extension website can teach you how much watering your grass species needs in local weather conditions. To track the amount of water you’re using, leave cans or other open containers on your lawn. Shaded grass usually needs less water, but this may not be true if it’s competing with tree and shrub roots.

Sandy soil drains fast, and may only need 0. 5 in. (1. 25cm) of water to reach a 6 inch (15cm) depth. The lawn has less time to absorb this water, so water more frequently to make up for it. Loamy soil takes roughly 0. 75 inch (1. 9cm) of water to reach a 6 inch (15cm) depth. Dense clay soil drains slowly, and may need 1–1. 5 inches (2. 5–3. 8cm) water to reach 6 inch (15cm) depth.

You can also dig into the soil to see how dry it is. Never water before the top two inches (5cm) of soil have dried out. [9] X Trustworthy Source University of California Integrated Pest Management Program Research-based pest management program run by the University of California’s Cooperative Extension Go to source If the lawn dries in a few spots, just water those areas extra.

While the grass is dormant in hot water, give it 0. 25–0. 5 inches (6–12mm) water per week. [11] X Research source

Do not water while the ground is frozen. Areas of shallow soil and exposed slopes are more likely to dry. Check south and west facing slopes especially (north and east facing in the southern hemisphere).

Older lawn care guides may recommend different heights for different seasons. Most modern experts agree that grass should be left tall year-round. [15] X Research source

For example, if the goal height is 2 inches (5cm), don’t let the grass grow taller than 3 in. (7. 5cm) before mowing. If the goal is 3 inches (7. 6cm), don’t let it get above 4. 5 in (11. 4cm).

Grass clippings do not contribute to thatch, as is commonly believed.

Slow release fertilizers are also called timed release or insoluble fertilizers. They include urea foam, IBDU, and WIN. Fast release fertilizers include urea, ammonium nitrate, and ammonium sulfate.

For example, a 9-3-6 fertilizer has a ratio of 3:1:2. The 3 numbers on a bag of fertilizer are known as an NPK ratio—this stands for nitrogen, phosphorus, and potassium, in that order. [23] X Expert Source Ben BarkanGarden & Landscape Designer Expert Interview. 14 April 2020.

Fertilize once a year, applying 1 lb nitrogen per 1,000 square feet (0. 5 kg / 100 m2). Late fall is ideal, but never during frost, snowy or soaked ground, or a heat wave following a frost. Fertilize every 8–10 weeks from spring to fall, using 0. 5–1 lb nitrogen per 1,000 square feet (0. 25–0. 5 kg / 100 m2) each time. Skip one of these if you leave grass clippings on your lawn after each mow. Look at a local university agriculture extension website for a guide that matches your grass species and climate.

Find the nitrogen percentage on your fertilizer packaging and convert to decimals. (For example, a 24-8-16 fertilizer is 24% nitrogen → 0. 24. ) Multiply this by the number of pounds of fertilizer per bag to get the pounds of nitrogen per bag. (0. 24 nitrogen x 20 lb bag = 4. 8 lb nitrogen per bag) Divide your lawn size by (1,000 x your answer). (2,880 sq ft lawn ÷ 4,800 = 0. 6 bags will fertilize your lawn). Pour that amount of fertilizer in your spreader and set it to a light setting. Walk around your lawn evenly until it runs out.

Drop spreaders are more precise, spreading less fertilizer outside the lawn. Minimize “striping” by setting to half strength and crossing the lawn in two paths, at 90º angles. Broadcast (rotary) spreaders are more efficient for large lawns, but must be kept at least 10 ft (3m) from water sources and lawn edges. To apply evenly, space applications so 30% of the spreader range overlaps.

Leave the plugs on the lawn to decompose. If they’re taking too long, break them up by dragging metal objects over the grass, or collect them to compost. [31] X Research source

The best way to remove thatch is additional core aeration, described above. Rent a dethatching machine to remove thatch less than 0. 5 in (1. 25 cm) thick. Do this only in early fall or late spring, when weather is cool and there are several weeks of growth left. Run a power rake over the lawn, frequently and shallowly. Deep power raking can cause damage.

Topdress the lawn with a ⅛ in (3mm) sprinkle of soil, using the same soil as the lawn. Conduct a soil test and adjust pH until it is between 6. 0 and 7. 0, or as recommended for your grass species. Add calcium carbonate lime to raise lawn pH, or sulfur to lower it. [32] X Research source Reduce use of pesticides, which may be killing earthworms that break down thatch.

Commercial wetting agents added to the water will reduce runoff, but won’t fix a serious problem. If your lawn is seriously compacted or has a thick layer of thatch, aerate the yard as described above.

Water less frequently but very deeply. Fertilize ⅓ or ½ as much as the sunny areas. Mow to 3 inches (7. 5 cm) or higher. Reduce foot traffic.

Never use fertilizers to break up ice, as they will run off along with snowmelt and pollute water sources. Stick to light use in early spring until the grass dries out and revives. If there are bare spots, seed them early before weeds take hold.