Allen D. Owings, Koske, Thomas J.
Mid-spring through summer is the best time for sodding, but dormant-season sodding can be successful. Planting dormant grass is simply more risky; winter environmental conditions may end up taking some of the sod.
In some cases, risks have to be taken. For example, if a golf course or game 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.
Sodding at any time is beneficial in reducing soil erosion, keeping mud from being tracked all over, reducing weed infestation and presenting a finished appearance to the landscape. In some cases, landowners may choose to seed ryegrass in the fall to hold things in check until a more advantageous season arrives.
Warm-season turfgrasses turn brown or mostly so when dormant. There is a difference in brown dead sod and brown dormant sod. Dead sod will still be dead next spring. Buy sod from a reliable source that will stand behind it. Sod is normally planted within 3 days of field cutting, but dormant sod should hold longer.
Cold weather brings on dormancy. Warm-season grasses grow slowly in soil below 70 degrees and stop growing below 60 degrees. Without growth, roots will not re-establish, 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 and has not been slowly hardened for winter. Without many roots, winter desiccation (drying out) damage is also a higher risk, but this can be avoided with adequate irrigation as needed.
Dormant sodding should be done with mostly-to-fully dormant sod. Sod that is in fall transition is more delicate to begin with. I recommend sodding at least 40 days before the first hard frost or waiting until after when the grasses are mostly brown. This sod will then have as much of a stored food reserve as can be expected. This reserve is important for a successful spring transition and green up.
Recommendations for grass establishment given on this AgCenter Web site also apply to off-season sodding. The tract should be properly graded 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. As such, unused fertilizer will be released into the environment and ground water. Incorporate lime or sulfur prior to laying if the soil test recommends either to adjust the soil's pH. Gypsum is applied if soil calcium is needed but no rise in soil pH is desired.
Lay sod slabs tightly together and arrange rows perpendicular to the slope. Stagger rows to create a brick-wall pattern. Never plant in a checkerboard fashion by skipping every other piece. Roll the completed lawn to press out air pockets and reduce root loss from desiccation. Water the sod well and repeat as needed to avoid sod loss to desiccation – remember, this sod will not have good roots until well after spring green up.
Do not play on or stress the sod until at least mid-spring.
Do not overseed a ryegrass for green color the first year. This overseed will compete with the short-rooted grass and make spring establishment more difficult.
Apply no herbicide that interferes with rooting, which includes most of them. If winter broadleaves appear, use a phenoxy type, 2,4-D broadleaf weed killer, but don't apply the typical weed-and-feeds in the first spring unless it's late spring.
At green up, apply a starter fertilizer that is high in phosphorus (the middle number on a fertilizer bag), or choose an analysis of at least a triple 13-type of blend. The soil-test results should be followed for best fertility results. Extra phosphorus is not needed if the soil tests high for it.