This summer has been favorable for weeds.

Unseasonably mild temperatures and timely rains have helped crabgrass, foxtail and nutgrass thrive in otherwise normally stressful conditions. As prime grass-growing weather approaches, now is the time to start rejuvenating cool-season lawns.

Getting rid of weeds is the first step in preparing lawns.

If there are a lot of weeds with little grass, start now. Annual weeds such as crabgrass, foxtail and the perennial dandelion can take over a lawn. They do not compete well with other plants, but when given enough light, water and space, they thrive.

Controlling these weeds is important to ensure that the grass seeds being sown have what they need to germinate and grow. If there is more than 60 percent weeds or less than 40 percent desirable grass, it is best to use a broad spectrum vegetation killer such as Round-up. This will kill everything and allow you to start from scratch. There is no lasting effects from the chemical, and seeds can be planted as soon as the vegetation dies within seven to 10 days.

If there are a few weeds with mostly good green grass, try one of the following options: Keep the weeds mowed. If they are annual weeds and not allowed to set seeds, the weed will die with the first frost and will not return next year. If they are perennial weeds, or you have more than just a few, use a post-emergent weed killer to selectively control the weeds and not harm the grass. The best product for controlling broad-leaf weeds is Trimec. It is a combination of three weed killers rolled into one. For broad-leaf and grassy weeds, use Trimec Plus. It is the same as Trimec but contains MSMA, a grassy weed killer.

When using these products, you must wait at least two weeks to work the soil and sow the seeds. For better results, spray the perennial weeds dandelion, bindweed and clover after the first light frost. Energy is being moved from the leaves to the roots so the chemical works more quickly.

Finally, if there are few weeds and little grass, or maybe even no vegetation at all, little needs to be done except for working the soil. Although it is a bit early to be planting the seeds, now is the time to prepare by gathering the needed supplies.