AgCenter warns against laying dormant sod in wintertime

April through October is the best time for sodding in Louisiana, but dormant-season sodding can be successful, but it is simply a little riskier.

In some cases, taking the risk is necessary. For example, some construction contracts require sod to be laid within 30 days or before house completion. Sod supply and contractor availability will be highest in this off season, too.

Warm-season turfgrasses turn brown or mostly so when dormant. There is, however, a difference in brown, dead sod and brown, dormant sod. Dead sod will still be dead in spring. Buy sod from a reliable source that will stand behind it.

Cold weather brings on dormancy in turfgrasses. The warm-season grasses we use for our lawns (St. Augustine, centipede, Bermuda, zoysia) grow slowly in soil below 70 degrees and stop growing around 60 degrees. Without growth, the newly laid sod will not produce a new root system, and rooting is the measure of establishment. The risk of freeze damage from an extreme cold spell is higher for sod that is not well rooted.

Preferably, sodding should be done with fully dormant sod. So, lay sod at least 40 days before the average first freeze in your area, or wait until after the freeze when the grasses are dormant.

Recommendations for grass establishment provided in online LSU AgCenter publications accessible at www.lsuagcenter.com also apply to off-season sodding. Delay fertilizing dormant sod because it is not growing and is poorly rooted. You should incorporate lime or sulfur prior to laying the sod if a soil test recommends either to adjust the soil's pH.

Lay sod pieces tightly together and arrange them in rows perpendicular to – across – the slope. Stagger the rows to create a brick-wall pattern. You should also roll the completed lawn to press out air pockets under the sod and reduce root loss from drying out. Water the sod well and repeat watering as needed to avoid sod loss to desiccation. Remember, this sod will not have good roots until well after spring green up. Water whenever you go about a week without rain. Don’t allow children to play on the lawn until at least a month after green up.

Apply no weed killers that interfere with rooting, and this includes most of them.

If winter broadleaf weeds are a problem, use a phenoxy-type 2,4-D broadleaf weed killer following label directions carefully. Don’t apply the typical weed-and-feeds in the spring.

In early to mid-April, apply a starter fertilizer that is high in phosphorus (the middle number on a fertilizer bag) if your soil is low in phosphorous. Soil test results should be followed for best results, and extra phosphorus is not needed if the soil tests high for it. In those situations, a typical lawn fertilizer will work fine.

Because dormant sodding done now involves some risks if we have unusually severe freezes this winter, you have an alternative. If you need to cover bare ground and would prefer not to – or can’t – lay sod until spring, you can plant annual rye seed over the area to stabilize the soil. And if you choose to plant annual rye, the sooner you do it the better.