The best time to fight crabgrass with pre-emergent herbicide is when forsythias tend to bloom. In the mid-Atlantic region, this is usually between April and May. Even if you're late to apply the herbicide, it’s effective as long as the crabgrass plant has fewer than five leaves.

There are tools known as “sprinkler donuts” that are specially designed to aid in cutting the grass around your sprinkler heads by protecting them from your mower or weed whacker. You can also use a pair of hand shears to do the job manually if you’re willing to get a little dirty.

Mowing a lawn will, unfortunately, not get rid of clover, and it may even encourage it to flourish. Let your lawn grow to a healthy height of over 3 inches and then set your mower blades no lower than this level. Higher grass will cut out the light that clover loves and discourage it from spreading.

The best way to prevent weeds is to use polymeric sand, which hardens and blocks weed growth when activated with water. If you're using regular sand, you'll need to refill and compact it more often. Keeping the surface clean and free of debris can also help prevent weed seeds from settling in the joints.