For Release On Or After 12/17/10

By Dan Gill
LSU AgCenter Horticulturist

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

In some cases, taking the risk is necessary. For example, if a golf course or athletic field has to be ready by spring, dormant sodding will give the earliest start to grass establishment. 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. Finally, when construction is finished, sodding is beneficial in reducing soil erosion, keeping mud from being tracked all over, reducing weed infestation and presenting a finished appearance to the landscape.

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.

If you get a guarantee for the sod you purchase and have laid, you may want to ask that the time be extended. Check with who is laying your sod about whether or not they are providing a guarantee and how long the guarantee lasts. Often, the guarantee will be for only three months or less. For sod laid now, three months is early March. The sod will not fully green up until late March or April, and you won’t be able to tell how well it survived the winter until then. So, arrange with your contractor to extend the guarantee until mid-April.

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.

Without many roots, sod is also at a much higher risk of drying out and suffering drought damage during winter. But this can be avoided with adequate irrigation as needed when the soil is dry. Just don’t keep it soggy!

Preferably, sodding should be done with fully dormant sod. Sod that is in fall transition is more delicate to begin with. 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. At this time, the sod being laid is mostly brown and dormant.

Recommendations for grass establishment provided in online LSU AgCenter publications accessible here also apply to off-season sodding. The area being sodded should be graded properly and lightly tilled. There should be no trash, rocks or weeds in the sod bed.

Delay fertilizing dormant sod because it is not growing and is poorly rooted. Most of the fertilizer applied during winter would be lost to leaching into the environment. 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. Lawn rollers are often available for rent from businesses where you rent other lawn-care equipment.

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. You don’t have to leave the sprinklers on for an extended period to water deeply because there’s no deep root system present to absorb water.

Don’t allow children to play on the lawn until at least a month after green up. It would be best to keep heavy traffic off of the lawn until May.

Don’t overseed newly laid dormant sod with ryegrass for a green winter lawn. Although overseeding healthy, established lawns doesn’t hurt them, the ryegrass will compete with the poorly established winter laid sod and make spring establishment more difficult.

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.