Steps for a successful Autumn reseed

Date published: 4 September 2024

College of Agriculture Food and Rural Enterprise (CAFRE) Beef and Sheep Adviser Jonny Brown says: “Reseeding is a cost-effective investment. When carried out successfully it will increase the amount of grass grown in a new sward compared to an old ley with the potential to reduce reliance on concentrates within an enterprise.”

Fields for reseeding should be selected on how they have performed over the growing season. Fields which have under-performed or fields that have been badly damaged by livestock or machinery should be a priority.

Once a field has been selected, it is important to consider some of the following points to ensure the reseed is a success:

Are there any drainage issues to correct?

Addressing problems associated with waterlogging is key to the establishment of the new ley. Carry out all remedial work prior to cultivations beginning.

Is there a compaction problem needing attention?

The correct way to determine the level of compaction present is by digging a number of test pits throughout the field to determine the depth the compaction problem exists. Compaction within the top 6-8 inches of the soil profile will be alleviated by ploughing, if it extends deeper in the soil profile then subsoiling may be a more effective option.

Soil fertility status?

Refer to Soil Nutrient Health Scheme (SNHS) soil analysis results if available and complete the CAFRE SNHS training to fully understand what the soil fertility status is. If no recent results are available, then carrying out soil sampling is recommended. This should only be carried out if no artificial fertiliser or slurry has been applied in the previous three months.

Pay particular attention to soil pH. A soil at pH 5 is ten times more acidic than that of pH 6. Optimum pH for grass clover swards is 6-6.5 for mineral soils.

Lime is best applied after ploughing but before secondary cultivations for a reseed. Application before ploughing causes lime to be buried excessively deeply in the soil leaving the surface of the soil acid. This can affect the uptake of nutrients such as phosphorus which is essential for root development.

Desiccating the existing sward with the correct product at the correct rate must be carried out carefully to remove competition for the new seeds against old grass and weeds.

By addressing the above points you will ensure that you have given the reseed the best possible chance for successful establishment. The earlier the new grass is sown the better. Like all new seeds, grass and clover are sensitive to soil temperature, so establishing the new growth prior to soil temperatures dropping is critical.

Cultivation method should be considered on a field-by-field basis. Where drainage work has been carried out, the ground has been poached or damaged by machinery then ploughing may be essential. Various methods of minimum tillage/direct drilling could be an option if conditions are suitable.

Selecting a grass seed mixture

Selecting a grass seed mixture should be carried on an individual farm basis.

If the field is for silage, look for varieties with traits for high D-value and dry matter yield. Remember that heading dates approximately ten days after your planned cutting date are required to ensure you achieve maximum silage quality. A close range of less than seven days between the heading dates of the varieties within the mixture will allow for better management of your sward.

Diploid varieties are predominately for increased ground cover while tetraploids have a tall growth pattern and can be more open on wetter soils.

The management of your sward post sowing will determine the inclusion of clover. Clover safe post emergence sprays will be required or alternatively clover can be stitched in six weeks after spraying.

Always use the Recommended Grass Clover Lists (RGCL) which includes varieties produced by the AFBI grass breeding programme at Loughgall. These grasses have been bred and trialled under Northern Ireland environmental conditions and information such as average yield potential, maturity, spring growth and persistence is available.

If you would like further information on managing an autumn reseed, then please contact your CAFRE Adviser through your local DAERA Direct office.