- 1). Cultivate grass that's adapted to your local growing conditions. Get a recommendation from your cooperative extension office or talk to someone at the local nursery. If it isn't feasible to rip the lawn and replant it, over-seed it with the recommended variety. Meet the requirements of the new grass to encourage it to take over the lawn area.
- 2). Mow your grass to the tallest height recommended for its species. As a general rule, maintain the blades at 3 inches.
- 3). Irrigate your lawn with 1 inch of water when the blades begin to wilt. Fertilize it with 1 pound of nitrogen per 1,000 square feet at the frequency recommended for your grass species.
- 4). Aerate the soil once a year. Insert a garden fork into the ground, and pull it out as you walk on your lawn. Rent an aerator from a tool rental shop, if the area is too large.
- 5). Hand pull oxalis as soon as it sprouts. Water the lawn to soften the soil and use either your hands to unearth its shallow roots or a hoe.
- 6). Apply a pre-emergence herbicide before oxalis reappears in spring. Spray the lawn with a product containing pendimethalin, oxadiazon or dithiopyr as its active ingredient. Check the product label before buying it to verify it's formulated for use on your type of grass. Read the manufacturer's instructions for the brand you selected for the proper application rate and frequency.
- 7). Spray each oxalis plant directly with a post-emergence herbicide. Use a pesticide that contains metsulfuron, trifloxysulfuron-sodium, sulfosulfuron or glyphosate. Apply it according to the instructions on the label after confirming the product is for use around the type of grass growing in your yard.
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