Agronomy Library > Soil Conservation

What is Sod Seeding?
Date Created: February 27, 2007
Last Reviewed: February 27, 2007

Sod seeding refers to no-till or direct seeding into a perennial grass or legume stand. Pasture and hayland renovation may require terminating the forage stand and converting it into an annual cropping system. See Removing Forages from the Rotation in a Direct Seeding System. Not all sod is equal, so start small and gain experience.

Traditionally, most producers in western Canada use some tillage (plow, heavy disc, and/or cultivators –with lots of harrowing) to terminate forage stands and prepare a new seed bed. These tillage operations are costly, time consuming, and put fields at risk to soil erosion.

Field trials in the 1990’s carried out by the Soil Conservation Branch of Alberta Agriculture Food and Rural Development, indicate that direct seeding of annual crops into pasture sod is feasible and it offers many benefits to growers. Some of these benefits are:

• Protection of land from wind and water erosion
• Better management of soil moisture
• Saving time, fuel, and equipment
• Reduced cost

Sod seeding streamlines the cycling of perennial forage crops in rotation. Combined with direct seeding, tillage is no longer required to switch from forage to annual crops and back. IMPORTANT NOTE: back-to-back re-seeding, or sod seeding new perennial forage into live or terminated old sod is not recommended.

Sod Seeding Recommendations
FORAGE TERMINATION - Allow 4-5 weeks of regrowth after harvest, or prior to the first cut, spray the forage stand with glyphosate ® *. Mid-summer to early fall applications are recommended for best results. This will optimize the decomposition of the existing root mass, including most forage species and perennial weeds. *Several GLYPHOSATE products are currently registered for PRE-HARVEST. Three to seven days after application, cut the crop for hay or use it for grazing. If cut much later than 7 days after spraying, hay quality may be reduced. Check labels carefully.

SEEDBED PREPARATION - After harvesting the terminated forage (baling grazing, etc.), next year’s crop can be direct seeded without extra field work or tillage – a no-till seed bed is preferred as it remains firm and moist which allows good seed/soil contact. Early seeding is essential to take advantage of spring soil moisture. Wait for sufficient rainfall if necessary. Seeding directly into sod requires different equipment than conventional seeding. A direct seeding implement that minimizes soil disturbance, such as with disc-type or narrow knife openers, is the preferred method of sod seeding. Be prepared to SLOW DOWN, compared to normal seeding practice.

ADEQUATE SOIL FERTILITY - Old pasture and unproductive hayfields are often nutrient-depleted. This becomes an important consideration when planning a crop rotation with sod seeding. Have the soil fertility analyzed for the intended crop and fertilize accordingly. Some one-pass direct seeding systems provide the opportunity of precision placement for crop nutrients in the design of a double-shoot seeder.

ACCURATE SEED PLACEMENT - Calibrate equipment and check seeding depth. For crop establishment in sod, good seed/soil contact is critical. Furrow closure and shallow packing of soil over the seed is vital when seeding in anything less than ideal moisture conditions. DO NOT STRAND THE SEED IN THE SOD (thatch layer).

REMAIN VIGILANT – Although seeding directly into well-rotted sod can reduce competition from volunteer regrowth and weeds, be prepared to use in-crop weed control strategies . Depending on environmental conditions, some form of insect and/or disease control may also be required.