Most farms sell what grows on top of the field. A sod farm sells the top of the field itself โ grass, roots and a thin layer of soil, rolled up like a carpet.
Sod is harvested by a machine with a blade that runs under the grass. It lifts the plants, their roots and a thin layer of soil all in one piece, and the pieces leave the field as rolls or flat slabs โ an instant lawn.
Basis: Standard sod production practice, described in university turfgrass extension guides.
A cut piece of sod has no field around it to hold water, so it dries out fast. The usual advice is to lay it down as soon as possible after cutting โ within about a day in warm weather โ and to water it straight away.
Basis: Lawn-establishment guidance from university extension services: install sod promptly after harvest and water immediately.
Most grasses grown for sod spread sideways, not just upward. Bermudagrass and St. Augustine send runners along the ground; Kentucky bluegrass sends them underground. Those runners knit the plants into a mat โ which is what lets a whole strip be lifted in one sheet.
Basis: Turfgrass science: the classic sod-forming grasses spread by stolons (above-ground runners) and rhizomes (underground stems); bunch-type grasses, which grow in clumps instead, do not knit as well and are harder to lift as sod.
Grasses also split in two by temperature: warm-season grasses (bermudagrass, zoysia, St. Augustine) grow hardest in summer heat, while cool-season grasses (Kentucky bluegrass, tall fescue) do most of their growing in spring and fall. Which kind a farm grows depends on where the farm is.
Basis: The standard warm-season / cool-season classification of turfgrasses used by university extension services across the United States.
Is that why so many of the leading sod states are southern ones? A longer warm season means a field can be ready sooner and cut over more months of the year โ the reason growers usually give. But a harvest count cannot separate the weather from how many new houses, parks and sports fields are being built nearby, so treat it as a likely story, not proof.
Every harvest carries a little of the field away with it, because the soil under the grass leaves with the roll. Sod growers have to keep building their fields back up between crops.
Basis: Sod harvest removes a thin layer of topsoil with each crop โ noted in extension guidance on sod production and soil management.
โป A hypothesis is an idea that isn't proven yet.
๐ Sources for the rankings mentioned in this note (links to the original data and retrieval dates) are on each quiz page below.