Establishing herbal leys

From seedbed preparation to post-establishment management, follow these tips for the successful establishment of herbal leys.

The key to establishing herbal leys is to know how the herbal leys will fit into your farming system. For example, will the ley be part of an arable rotation, temporary ley, or stitched into permanent pasture? This will determine the species you will use and the optimum planting window for the ley.

James Drummond from Lemmington Hill Head farm in Northumberland has set up a grass-herb trial with ADAS to look at sward and livestock performance. Check out the video below to find out more about the species mixes, fertiliser treatments, establishment methods and results so far.

Seedbed preparation is crucial to the success of a ley. Power or disc harrow at shallow depth, then roll pre-sowing to get an even seedbed. Optimum pH differs, as many species prefer different conditions.

Weed control for herbal leys needs to be planned pre-establishment, as the mix of grass and broadleaved species limits herbicide options. Things to think about:

• Consider the timing of sowing – autumn sowing may be better than spring
• Plan for weed risks on your farm and in your rotation – beware of the seed bank you may have in the soil
• Spot spraying is a possibility, but beware of drift – the species in herbal ley mixes tend to be sensitive to herbicides
• Topping or mowing can be useful – docks can be spot-sprayed or manually removed

Ensure the seeds are sown into warm, moist soil, as legumes, clovers, and herbs need 8–10 degrees to germinate. This is typically from late April until the start of September. Seeds are small, so sow no deeper than 1 cm. The main reason for poor establishment is when seeds are sown too deep. Seed rate needs to balance having a robust sward and smothering delicate species. Sowing methods for herbal leys include:

• Broadcast – allows shallow seed depth, or
• Drill – no deeper than 1 cm.

Roll twice after sowing for soil-seed contact. Remember, choose a sowing method that will work best with your system.

If planning on overseeding, cut or graze hard, or harrow to open the sward. This will also reduce competition. Broadcast the seed and leave stock off for 4–6 weeks to prevent damage.

Protect seedlings for 6–8 weeks post sowing, then lightly graze. This will help weed control and encourage tillering. 

Rotational grazing is the best way to manage herbal leys. Rotations can be anything between 20–40 days but are typically 28–38 days. Set stocking on herbal leys can lead to reduced species diversity in the ley, as livestock will selectively eat the palatable species.