How to make grass-to-grass reseeding work

Friday 28.06.2024 , News

Following a wet and difficult spring, many farmers have been reseeding damaged grassland or overseeding to reinvigorate pasture. Germinal expert Paul Morgan says farmers want to ensure forage quality is high in case they have another long winter ahead.

Ideally, a brassica like Redstart will be used as a break crop before establishing a new grass sward. However, circumstances might not be on your side and a grass-to-grass reseed will be necessary.

With grass-to-grass reseeding, it is riskier because the pest burden will be heightened. When there is insufficient time to establish a break crop, other steps can be taken to reduce the pest risk.

Reduce pest risk when sowing grass back-to-back

For wireworms, the consolidation of seedbeds can help restrict movement. A minimum two-week break from grass-to-grass leys is recommended so the pests have nothing to eat.

This can be achieved by ploughing and leaving the area as fallow. Ploughing in July can reduce leatherjacket populations by 50%.

While autumn reseeding is best for controlling leatherjackets, spring reseeding is advised to prevent frit fly attacks. This is because the reseed will fall outside of the main egg-laying period of July to October.

Checklist: Reseeding and overseeding

Test soils six months beforehand to establish soil pH. The target is 6.5 while potassium and phosphorus should be index 2. If overseeding, skip to step four – otherwise, continue to step two.
Spray off the existing grass ley.
Decide on your reseeding method (see table of grassland reseeding methods compared).
When overseeding grassland, remove all thatch using a harrow. This might require two to three passes. Work in a crisscross pattern. If there is a heavy amount of thatch, use a Calciprill to neutralise the acidic layer.
Once the soil temperature hits 8-10°C and is rising, drill the seed, but no deeper than 1cm or the seed could fail to germinate. When overseeding grazing leys, use perennial tetraploids, not Italians. These are better suited for grazing and do not go to head as quickly.
Use a grass variety on the Recommended List which can withstand GB conditions and will perform well. Grass should be sowed at 14kg/acre and white clover 1-1.5kg/acre, depending on soil indices. If indices are low, go for the higher rate to achieve a better strike.
Whichever reseeding method is used, rolling is critical to achieve good soil-to-seed contact. If dry, it is advisable to roll the field twice, but only once if it is wet to prevent soil capping.
Before grazing the crop, carry out a ‘pull test’. Tear off a handful of grass – if the whole plant comes out, it needs more time to establish. If just the leaf tears, it is ready to graze.
Field conditions permitting, graze lightly (just the first leaf) at a high stocking rate for a short time to encourage tillering.