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To Sod or to Seed?
© 1997, 1998 Streamline Publications
Instant landscape! Dirt today—
tomorrow, lush greensward. That is the promise of sod. And if everything
goes just right it could work out. But sod can be an expensive trade-off for
traditional seeding or hydroseeding. The advantage of a sodded landscape is
obvious—instantaneous, mature grass. In some cases nothing can equal its
convenience. Ask a developer eager to open his model homes if he wants to wait
for the grass to grow.
"That's the beauty of it, Charlie. Yesterday we sold sod, but now that it's hardened up we can sell it for brick.
The fallacy of sod is that it can just
go off the truck and onto the ground— line up the edges like kitchen floor
tile, wet it down and then it's Miller time. The reality is far different.
Unless the soil under the instant carpet of green is properly prepared—the
same as it has to be for seeding—the roots of the grass will not take hold.
Consider that the sod is grown (from
seed) in fields that have been cleared, leveled, tilled and amended to achieve a
healthy stand of grass. Then sod cutting machines, set to a minimum depth to
avoid taking too much soil, slice the grass away from its root system. The
plants, which are in shock, are then subjected to handling. The sod "tiles"
are folded and stacked on pallets awaiting installation. Hours or days may pass
before the grass comes in contact with soil, nutrients or water. Sod could be installed on a
wooden-floored basketball court and remain green for a time, but eventually it
will become nothing more than dry grass. For sod to be successful the soil must
be able to immediately nurture the grass and bring it back to health. When this
vital step is overlooked by the client and the contractor both are sure to end
up unhappy when the sod dies out—an expensive omission. Healthy sod on nutrient-poor, packed or
rough soil, such as on engineered slopes creates a "perched" water
interface. This doesn't allow drainage of top-applied water down through the
soil or upward movement of water and nutrients to what little root structure is
left on the sod. Water trapped in this interface can bring on fungus and prevent
the sod from establishing deeper roots. It is the very ability of sod to remain
green for weeks or even months that masks sprinkler problems too. By the time it
is obvious that sprinkler coverage is inadequate, the sod is dead in that area.
Seeded turf will make such deficiencies obvious early on by stunted growth or
simply failing to germinate. Modifications or repairs to the irrigation system
can be effected and the area reseeded within days.
The Cost DifferenceTypically, sod can run up to 35 cents a
square foot—and more—plus installation costs. Traditional seeding will
run 1/2 to 3-1/2 cents a square foot and hydroseeding about 15 cents for the
same coverage—including labor. Material costs to drill-seed and fertilize
an acre, versus sodding, translates to under $225 for seed and more than $15,000
for sod. If the sod fails, it is a significant loss necessitating removal and
starting over. Sodding is labor intensive, taking
many work hours. And while just 7,500 square feet of sod would have to be
delivered on a pair of ten-ton flatbed trucks, seed for the same area fits in a
car trunk. Sod has been known to transfer
soilborne pathogens and nematodes—root parasites that steal nutrients from
the already-stressed plants.
A Matter of Choice
Because sod is a perishable, living
product that represents a significant investment for suppliers, only the most
popular grass varieties in limited mixes of cultivars are available. Seed mixes,
conversely, can be formulated to meet the special requirements of a particular
soil or microclimate. The low cost, variety and manageability of seeded turf
make it the smart choice in all but a few applications. Sod or seed? The answer's easy when you
think about when and where you want your green—today or tomorrow—on
the ground or in your pocket. It's your choice.
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