How early can I put down Malathion?
Two heavy drenches, 10-15 days apart are best. That will usually take care of ticks hatching first, and fleas, later. It does not work on eggs, so flea hatchlings must be active. Adult ticks can be killed anytime, but their eggs also require hatchlings be active.
IT IS DEADLY TOXIC TO FISH SO KEEP AWAY FROM WATER GARDEN, especially if lawn-rain runoff gets into pond.
Grass begins growing when soil temps hit 50-52°F, so that should be the sign to spray. Keep animals and humans off the affected areas for 3-4 days, until all chemicals are absorbed by soils and lawn root system.