Nematodes offer a natural alternative for eliminating grubs. Application time depends on the size of the lawn. Application requires a water hose and hose end sprayer. Nematodes are available online and from organic garden supply stores.
- Refrigerate nematodes until ready for use
Unless applying the nematodes immediately upon their arrival, store them in a refrigerator up to two weeks until ready to use. Store the nematodes at temperatures between 37 and 42 degrees Fahrenheit.
- Check the soil temperature
Apply nematodes when soil temperatures are between 42 and 90 degrees Fahrenheit. Normally, nighttime air temperatures should remain above 45 degrees Fahrenheit. If soil temperatures have dropped below the minimum, wait until after the dormant period to apply the nematodes. Grubs do not damage plants when the soil temperature drops below this range.
- Apply the nematodes
Use a hose end sprayer to apply the nematodes. If there are nematodes left after the first application, reapply to meet the suggested rate.
- Water the grass
Irrigate the lawn after application. Keep soil moist by watering every three to four days.
- Reapply nematodes before and after dormant periods
Nematodes are sensitive to drought and temperatures. If you see signs of grubs after an extended hot and dry period, reapply nematodes when soil temperatures reach the appropriate range. If soil temperatures drop below freezing, apply more nematodes when soil temperature warm to 42 degrees Fahrenheit and the grass starts to grow again.