The directions on Scotts products are kind of vague since they have to cover a wide variety of customers. Since Hewitt’s only has locations here in the Capital District of NY. I’ll assume that you are local and give you this tip for applying crabgrass preventer in this area. The most effective way to stop crabgrass is to apply crabgrass preventer right at the end of the blossom cycle of the forsythia bush right as the flowers are dropping off (just as the lilacs begin to flower). This stops the crabgrass seeds from sprouting and since crabgrass is an annual that grows from seed each year, it is a very effective control. Very often a customer will apply their crabgrass preventer just as soon as the lawn greens up. Since crabgrass only acts on crabgrass during the sprouting phase waiting a bit and using the timing I described above will give better results. Since the crabgrass preventer form a thin film on the surface of the soil it is vulnerable to getting eroded or washed away before it has a chance to act on germinating crabgrass seeds. The opportunity to use crabgrass preventer has passed for this season so the spray is your only option at this point. Repeat sprayings will likely be necessary. The chickweed and clover killer you used will work but needs to remain in contact with the LEAVES of the weed for at least 20 hours (and longer is better). If you watered or it rained within 24 hours of your application then the herbicide was washed off the leaves and it won’t work. Remember, weed killers are absorbed through the LEAVES of the weeds. They will kill the roots but must be absorbed by the leaves.