Finding the best way to reseed pasture

Keeping your grassland healthy and productive is a vital part of livestock farming enterprises. This can be achieved by figuring out the best way to reseed a pasture.

Productive swards provide an extremely cost-effective feed, costing just 5p for 1 kg DM of grazed grass and 10-12p for 1 kg DM of grass silage. To achieve this, swards must be reseeded regularly with high-performing agricultural grasses well suited to the farm’s requirements.

Regular reseeding

Start your pasture reseeding plan by walking your farm to examine each sward, looking for areas of concern. And pay particular attention to the more mature swards. These will have a higher proportion of weed grasses and likely to be less productive.

Signs of an unproductive sward suitable for a reseed:

• High proportion of unproductive grass varieties including bents, meadow grasses, red fescue and Yorkshire fog
• High number of weeds such as docks, thistles, nettles and chickweeds
• Reduction in silage production or stock carrying capacity
• Rejection by livestock or uneven grazing
• Slower regrowth, intermittent growth or reduced response to fertilisers

The long-term aim of a reseeding plan is to ensure swards do not deteriorate over time and remain as productive as possible. To gain the most from your swards, aim to reseed around 10-15% of your farm each year.

Use high-quality agri grass seed mixtures

To implement a successful reseeding plan and maintain grass quality, pick your seed mixtures carefully. Select grass varieties bred specifically to support livestock production, as these result in the most effective conversion into milk or meat. They are also 25-50% more responsive to nitrogen than mature permanent pasture.

Select a mixture with grass varieties on the Recommended Grass and Clover List (RGCL). The difference in performance between the highest and lowest-ranked varieties can be substantial. Varieties on the RGCL are tested in Britain under trial conditions over a four-year period. So, you can have confidence in their performance in this country.

Ask your merchant if the varieties in your grass mix are on the RGCL. The list acts as a safeguard, so you know you are buying the best. If your varieties aren’t there, ask why.

To best fulfil your production goals, a good mixture for livestock should strike a balance between quantity (DM yield) and quality (D-value). Other agronomic factors, such as seasonal growth, ground cover and disease resistance, also influence performance so should be considered.

Soil health check

Before you start reseeding, carry out a quick health check of your soil to make sure conditions are right. For optimum growth, soil pH should be 6-6.5, with P and K indices of 2.

Addressing any deficiencies well in advance is important for a successful reseed. In the long term, carrying out regular soil health checks and addressing problems as soon as they occur helps ensure your swards remain productive.

Choose what is right for your farm

Deciding how and when to reseed largely depends on your farm type and soil conditions. Whichever method is used, always aim to produce a fine, firm seedbed to maximise seed-to-soil contact and increase the chance of successful germination.

Sowing when soil is moist and at least 5°C also increases your chances of success. And so does using the correct seed rate of 15 kg/acre or 35 kg/ha at an optimum seed depth of 10 mm (maximum 15 mm).

Ploughing is usually best where soil compaction is an issue. However, for those with stony soil, minimum tillage is more suitable to avoid disturbing too much topsoil. Whichever method you use, following best practice and good post-drilling management maximises your chance of success.

Spring vs autumn

Whether done in spring or autumn reseeds can be successful, the timing largely down to your farm and soil conditions. Spring provides a wider window of opportunity with generally better weather and soil conditions favouring good growth and effective control of post-emergence weeds with herbicide sprays.

But spring reseeds leave swards out of use at their most productive, with the soil too tender for travel or grazing in the early stages.

An autumn reseed has a narrower window of opportunity, with poorer weather conditions and soil conditions worsening as the season progresses. But autumn provides the prospect of a sward reaching its full production potential over winter and gives the soil time to settle before travel or grazing in spring.

Both spring and autumn reseeds allow break crops to be grown. This can be a useful tool for farms looking to break grass-specific pest, parasite or disease cycles. They can also control weeds and address issues with soil nutrients or condition, along with providing a useful forage crop for livestock.

Best way to reseed a pasture? Overseeding also an option

Overseeding grassland can give a short-term boost to production when a complete reseed is unsuitable. This can be when leys still have at least 50% perennial ryegrass species and the type of land makes a full reseed challenging.

Overseeding grassland is also a good way of starting a reseeding programme on-farm if you are heavily stocked or don’t want to take a field out of production for any length of time.

To make it effective, aim to overseed between July and September after either tight grazing or a silage cut. Use a seed rate two-thirds of the full reseed rate, around 10 kg/acre, and ensure good seed-to-soil contact by harrowing and rolling as required.

For advice on reseeding agricultural grassland, contact one of our grass and forage experts.