[VOA农业报道]Yard Work: When People Choose Sod Over Seed
By Jerilyn Watson
2009-7-6
This is the VOA Special English Agriculture Report.
For some people, the road to immediate satisfaction is laid with sod. A piece of sod has grass on the top and soil on the bottom. It can provide thick green grass without the work or wait required to grow a lawn from seed.
Some property owners are replacing grass with ground covers that require less care and water. But others want a traditional grass lawn. Sod, or turf, might not seem like a farm crop. But farmers grow it around the world for everything from homes to sports fields.
Sod farmers often grow different grasses for different conditions. Farmers must cut, fertilize and water the sod often. The crop may not be ready for up to two years. Farmers harvest it in pieces of various lengths and up to one meter wide.
Making the best of sod takes work. Preparing the ground to lay sod is important and may require soil amendments.
David Robson from the University of Illinois Extension says the best results come from moist, richly organic black soil. He says that is because the farmer used rich soil to produce the sod, so it might not do well in clay soils.
Some gardeners prepare an area by removing the existing top soil and grass. This can be done with a shovel, hoe or sod-cutter machine. But live roots or weeds might remain below the surface.
Another preparation method is to till the ground completely. Still another involves using an herbicide chemical to kill the existing grass. Sod can also be placed over existing grass. The grass will die and become fertilizer for the sod.
After sod is in place, it needs to be pressed down firmly. This will remove air pockets and help the sod make contact with the ground and take root. A water-filled drum called a sod roller can be used.
Sod can grow at times and in places where growing grass from seed is difficult. But sod can also have problems, especially if it was not very fresh. Newly laid sod needs water -- lots of water. It can quickly become dry. It will need water two times a day for at least three months. Sod should also be fertilized. And it should be treated with limestone if the soil is acidic.
Sod can be cut to fit a space. But small pieces should not be placed along the edges of an area as they can dry out more quickly.
You can find other advice online. For example, we learned that sod should not be placed so that the ends of the pieces are all in a line. Instead it should look like a brick pattern on a building.
