In the Spring we need to wait for the soil temperature (not the outside air) to reach 10 degrees, nematodes can’t live in soil that’s too cold. The best time to plan is the first week in May, traditionally the soil is warm enough to germinate grass seed. The second application should be done just after September 15th, we have shorter days and cooler nights that make ideal conditions for an application. Crane flies do not lay their eggs before the 15th of September, we do not start treatments until all bugs are done laying their eggs for the season.