Removing all weeds from your lawn are is necessary prior to sodding. Weeds disrupt sod's ability to establish strong root systems in the soil by taking up sun, air and nutrients. Gardeners looking to clear a large area of weeds prior to laying sod may want to consider applying Roundup brand weed killer because its active ingredient, glyphosate, leaves little soil residue that can kill your new sod. Time spraying your lawn with Roundup, so the residue is out of the soil when they sod. Moreover, removing the weeds is only part of the site preparation you must conduct before sodding.
Gardeners should water their lawns for two weeks before spraying Roundup. Watering the lawn will promote weed growth. Vigorously growing weeds are easier to kill with this non-selective herbicide, because the more foliage the more toxic chemicals the plant will absorb. Choose a dry, windless day to spray the herbicide. Roundup needs at least 24 hours of dry weather to be effective. Walk across the lawn and spray an even spray of the herbicide to ensure you completely remove your weeds.
How Long to Wait
Wait three to four days before spraying Roundup again to remove any weeds that were not killed off from the initial herbicide application. Plan to sod your lawn in five to 14 days after the second application of Roundup. Avoid waiting too long, because weed seeds will take advantage of bare soil and the lack of competition from other plants. Give yourself enough time to be able to prepare the soil with starter fertilizer, which should be applied the day before or day of your sod installation.
Spread a starter fertilizer over your soil. A starter fertilizer is high in phosphorous, which helps sod establish in the yard. You can use 20 lbs. of starter fertilizer with a nitrogen-phosphorus-potassium (NPK) amount of 5-10-5 or 5-20-10 per 1,000 square feet. Work the starter fertilizer into the first 2 to 4 inches of top soil with a tiller. Smooth the lawn area with the back of a rake.
When to Sod
Sod your grass on a day that is not too hot. Sod's roots can quickly dry out during hot summer temperatures, which is why numerous gardeners choose either the spring or fall to install their sod. Try to sod your lawn as soon as the sod has been delivered and you have inspected the sod pieces. Avoid accepting any sod that is thinner than an inch. Also, look for weeds and pests in your sod pieces.