Your St. Louis Spring Lawn Prep Checklist
Posted April 2026 · Metro West Lawn & Landscape
What you do (and don’t do) in March sets up your lawn for the entire growing season. Six action items, one thing to avoid, all timed for the St. Louis Metro West climate.
1. Cleanup — rake, blow, and remove winter debris
Wait until the ground has dried out (usually late February to mid-March). Rake or blow off leaves, twigs, and dead grass. This lets sunlight hit the soil so it warms up faster and exposes your lawn for inspection. Don’t skip this step — debris matted on the lawn invites snow mold.
2. Inspect — identify damage from winter
Walk the property. Look for: bare patches, snow mold (gray or pink fungal patches), salt damage near walkways and driveways, and turf compression in high-traffic areas. Note what you find — it dictates the rest of your spring work.
3. Pre-emergent — apply when forsythia blooms
Crabgrass starts germinating when soil temps hit 55°F — usually late March in Metro West. Apply pre-emergent crabgrass treatment when forsythia bushes start blooming (a reliable visual cue). Apply too late and crabgrass already germinated. Apply too early and it breaks down before it’s needed.
4. Liquid aeration — the spring jumpstart
This is the single highest-ROI spring treatment. A liquid soil conditioner penetrates Missouri clay, breaks compaction, and feeds the lawn as it wakes up. No holes in the lawn (unlike fall mechanical aeration), no disruption of pre-emergent applications. We do this for hundreds of customers in March-April every year. Read more about liquid aeration here.
5. First fertilizer application — mid-to-late April
Wait until the lawn shows active growth before fertilizing. Apply a balanced spring fertilizer (something like 20-5-10) at the recommended rate. Don’t over-apply — too much nitrogen too early forces excessive growth that the root system can’t support, and you’ll burn out by July.
6. First mow — when grass hits 4 inches
Resist the urge to mow early. The first mow should happen when grass is about 4 inches tall, and you cut it down to 3.5 inches — never more than 1/3 of the blade. Sharpen the mower blade before the first cut. Dull blades tear grass instead of cutting it cleanly, which causes the brown-tip look that plagues most home lawns.
DO NOT: dethatch unless you actually have heavy thatch
The most common spring mistake we see. Power dethatching looks productive — but for most St. Louis lawns, the thatch layer is fine and dethatching just rips out healthy grass. Only dethatch if your thatch layer is over 1/2 inch thick (push a screwdriver into the lawn and measure). Otherwise, fall aeration handles thatch reduction over time without the spring damage.
Spring landscape work too
Spring is also the perfect window for landscape installation projects: new beds, mulch refresh, replacement plants, hardscape, and shrub trimming. Soil is workable, plants are entering active growth, and you have the whole growing season to enjoy the results. See our landscape design service.
If this feels like a lot
It is, honestly. Six action items at the right times, with the right products, in the right windows — that’s a lot of expertise to ask of a homeowner who has a real job. Our weekly mowing program includes most of this automatically: timed fertilization, pre-emergent application, mowing height adjustments. Liquid aeration is an add-on most customers bundle in. See our weekly maintenance program.
Or just call us. We’ll handle it.
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