When establishing a lawn, sod gives immediate results. Seeding may cost less money (approximately $30 per 1,000 square feet compared to about $200 per 1,000 square feet), but it requires several months of patience and high maintenance to get a uniform, mature lawn. Seeding starts out thin as small seedlings that leave ample space for weeds to establish and compete with turf. Seeding is more feasible in the North because seed like ryegrass and fescue will germinate and establish quickly; but options in the South are limited to moderate to lengthy germination periods.
WHEN TO SOD
Anytime during the growing season is a fine time to sod as long as water is available. Spring and fall are optimal since temperatures are more moderate and turf is under less stress. In the South, some species of grass can be sodded throughout the winter.
Prepare a soil sample to test for pH and nutrient levels. The pH is the measure of soil acidity on a scale of 0 (acidic) to 14 (basic), 6.5 being ideal for most turfgrass. Tilling fertilizer into the soil about 6 inches deep is best for some nutrients that are non-mobile, such as phosphorus and potassium. Soil test results will suggest treatments to bring pH and nutrients to optimal level, if needed.
You will need to order sod ahead of time. Unless you have a trailer, have the sod delivered to the site. Each pallet weighs about one ton. One pallet will cover approximately 500 square feet, depending on the species (check with supplier). To estimate the number of pallets needed, calculate the number of square feet to be sodded. Break the area up into rectangles, triangles and circles to figure the total square footage of the area.
Rectangle: length × width = square feet
Triangle: (base × height)/2 = square feet
Circle: (radius squared) × 3.14 = square feet
Once you have estimated the total square footage, divide by 500 square feet (or however many square feet a pallet covers) to calculate the number of pallets you need.
Spray the area with non-selective herbicide a week ahead of time to prevent any reestablishment of unwanted weeds. A systemic herbicide, such as glyphosate, will translocate to underground growth for better control than a contact herbicide. Remove existing vegetation with a sod cutter or rototiller. Sod cutters work fine if the existing grade is acceptable. This will also take the grade down an inch for the sod to be laid up to the final grade.
Tilling the area will allow for regrading the area and raking out debris. Tilling also can relieve compaction by loosening the soil and improving the structure. You can work treatments for pH or nutrients into the soil at this time. Rake the grade with a garden rake, or similar steel rake, and remove clods, clumps of grass, sticks or other debris. Level the grade so that it is about one inch below the final grade to allow for the sod. Be sure there is enough space along edging, curbing, sidewalk or driveway for the edge of the sod to lay flat against it instead of above it. Exposed edges will dry out quickly.
If the soil is dry, lightly water it just before laying sod to cool the soil and reduce the shock of temperature and lack of moisture.
Sod comes in either pieces or rolls. In areas where soil is sandy or the turfgrass does not vigorously knit together with stolons or rhizomes, the sod will be cut into pieces because it does not hold together well. If you're cutting your own sod, set the depth to about ½- to 1-inch deep, as long as the sod holds together. Cutting sod thinner will reduce the amount of soil that is removed from the area and also the weight of each piece or roll (your back will appreciate that). Cutting it thin will also stimulate the turf to root into the soil quicker. Although thicker-cut pieces take more roots with them, they also take longer to “peg down,” or root, into the soil and establish.
If you're having sod delivered, have the pallets dropped off around the area you'll be using them to reduce transporting them. Sod will last on the pallet in summer about 48 hours before it expires. Cooler temperatures can keep the sod alive longer. If you need to store it, put it in the shade and, if possible, unload the pallet so that pieces or rolls are not stacked, then lightly water them. Heat builds up in stacked sod from transpiration and microbial activity that reduces the time sod remains viable.
Laying sod is easiest when started along a straight line, like the edge of a driveway or sidewalk. Lay the first row of sod so that the edge of the sod is firmly against an edge and not exposed. Exposed edges will dry out and die.
Place each piece end-to-end and make sure they are tightly fitted with no space in between. Sod will shrink after a few days and expose edges that will dry out and shrink even more. This will leave a sodded area uneven with large cracks and dead grass at the edges. Also avoid stretching pieces when laying sod because it will be susceptible to additional shrinkage.
Lay each row so that the ends of the pieces do not line up with the adjoining row, but create a staggered pattern. This will reduce the seams from running across the rows.
If laying sod along a steep slope, run the rows across the slope and use biodegradeable stakes to reduce slippage. The stakes will hold the sod in place until it is established, then decompose so you don't have to remove them.
Fit pieces into irregular spaces by either ripping apart a chunk to fit or cutting it. Cut pieces to fit irregular spaces with a large knife, hatchet or spade. You can easily cut pieces to fit by overlapping and cutting around the outline of the top pieces or the outline of the bottom piece. Remove the cut piece and lay the remaining piece in place for a perfect fit.
If sodding a section of turf in the middle of ground, do not leave edges exposed. Tuck the edges of sod into the ground by cutting a lip into the soil with a spade or knife.
Once you've laid all the sod, put all pieces into place and tucked all the edges, you should roll the area. A water roller is a drum that is filled with water to give it weight. Rolling the sod will improve root contact with soil and remove any air pockets. Air pockets can reduce establishment because there is little contact between roots and soil. Better root-to-soil contact will quicken the pegging down of roots into soil and establishment.
Water sod as soon as possible. If sod is out on dry soil in the full sun for a couple of hours before watering, die-back can begin and increase the amount of time for establishment. Water until the soil beneath is wet. Pull up pieces in several areas to insure that adequate penetration is achieved. Water everyday for a week if there is no rain. All the roots are located in the sod, so the turf is dependent on irrigation for water requirements until it can establish a root system in the soil. In hot weather, you may need to irrigate sod more than once a day to cool it as well. Continue watering frequently for the first two to three weeks and avoid dry soil. Once roots have established after this period, water less frequently and more deeply to encourage deep rooting. Apply an inch of water per week over two to three applications.
Cracks usually appear when sod has been allowed to dry too much or pieces have not been fitted tightly. You can fill these cracks with soil to level the ground and reduce further drying out of edges. Once established, the turf will tiller outward and fill the cracks.
Do not fertilize until the sod has pegged down. Turf is under a great deal of stress because it has had greater than 90 percent of its root system removed. Fertilizer will be most efficient and effective when you apply it after roots have firmly penetrated the soil. Apply one pound of nitrogen per thousand square feet, then follow fertilizer recommendations after that.
Mow the sod only once it has pegged down. Mowing too soon can pull pieces up into the deck and shred them. Mow at the proper height so that no more than ⅓ of the topgrowth is removed.
Customers usually are satisfied with the additional costs of sodding because they see a yard of bare soil turn into a stand of mature turf overnight. There are few weed problems to tolerate and establishment requires much less effort than seeding.
Tony Bertauski is a horticulture instructor at Trident Technical College (Charleston, S.C.).
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