According to the Fertilome Weed Free
product label: Spring and Fall treatments under adequate soil moisture conditions are preferred to the Summer treatments. Generally, Summer broadcast applications to older, drought stressed weeds are less effective. Broadcast (entire areas) applications or follow-up applications at 2-6 week intervals are recommended for more mature Weeds, for dense infestations, and for adverse environmental conditions. Spot treatments during summer may be appropriate for sparse infestations, or as a follow-up treatment, or any time broadleaf weeds are susceptible. For more specific information or application tips we recommend that you contact the manufacturer directly. You can reach VPG at 888-583-5296.