https://defrafarming.blog.gov.uk/create-and-maintain-herbal-leys/

Create and maintain herbal leys

Find out how land managers can improve soil health and provide food for pollinators in arable rotations by creating and maintaining herbal leys.

If you’re completing this action as part of the Sustainable Farming Incentive pilot, how you do it is up to you.

The advice on this page can help you get better environmental and business benefits, but you do not have to follow it to get paid.

Herbal leys

Herbal leys are temporary grasslands made up of legume, herb and grass species.

You can sow herbal leys on arable and horticultural land, vegetable fields and temporary grassland. Herbal leys easily fit into arable and mixed farming rotations.

Compared to grass-clover leys, the wide variety of plant species in herbal leys:

provide more flowers, so they are a better food source for pollinators like bees, butterflies and hoverflies
improves soil structure, which benefits soil fauna and increases soil organic matter
increases soil fertility, as legumes add nitrogen to the soil
captures more carbon from the atmosphere and transfers it to the soil as organic matter
reduces runoff, as better soil structure means more water can get into the soil

Business benefits

You can increase the diversity of forage and reduce the need for supplements. Diverse forage includes:

grasses that provide energy
legumes that provide protein
herbs or wildflowers that provide minerals
plants like sainfoin, chicory or bird’s-foot-trefoil that control parasites naturally

Herbal leys:

lower manufactured fertiliser and herbicide costs
increase crop yield and quality due to improved soil health
help control weeds like blackgrass in arable rotations
protect against adverse conditions like drought, as deep-rooting species can reach water deeper in the soil

What to sow

The seed mix is vital to growing a high quality herbal ley. Your seed supplier can help you choose a seed mix to best match your land, local conditions and how you’ll manage the ley.

Choose a seed mix which has at least:

5 species of grass
3 species of legumes
5 species of herbs or wildflowers

Legumes mixed with herbs or wildflowers need to make up at least 25% of the mix’s weight.

When designing a seed mix:

balance cost with ley duration - cheaper legume and herb varieties will not last as long
increase the seed rates of legumes and herbs if you find they do not last long in your leys
use sainfoin on soils high in calcium carbonate - it’s hard to establish well on other soil types
consider chicory only if you can graze it - the tough stems pierce hay and silage bale wrapping
choose deep-rooting species

Festulolium and perennial ryegrass combined should not make up more than 50% by weight of the total seed mix.

You must use organic seed if you farm organically or are converting to organic farming. You’ll need approval from your organic certification body to use non-organic seed.

Suitable species for herbal leys

Grass species you can include in your seed mix are:

cocksfoot
festulolium
meadow fescue
perennial ryegrass
smooth-stalked meadow grass
tall fescue
timothy

Legume species you can include are:

alsike clover
bird’s-foot-trefoil
lucerne
red clover
sainfoin
white clover

On historic features, do not grow plants whose roots could damage the features. These include deep rooted legumes like sainfoin and lucerne.

Herb or wildflower species you can include are:

burnet
chicory
ribwort plantain
sheep’s parsley
yarrow

If you cut your herbal leys but do not graze them, you’ll need to choose species in your seed mix that:

can cope with regular cutting
grow at similar rates, as fast growing species can smother slow growing species between cuts

How to create herbal leys

Sowing herbal leys into weed-free seedbeds

You can sow into a weed-free seedbed or direct drill into stubble. This is the most reliable technique for creating herbal leys.

Create a well-consolidated, firm, fine, level and weed-free seedbed before you sow, to improve germination.

You can roll seedbeds before sowing, if they are uneven after secondary cultivations.

You can raise pH with lime or phosphorus (P) and potassium (K) with PK fertiliser. Clovers grow better in soil that is above 6.0 pH and above index 2 for P and K.

How to sow

Sow herbal leys when the soil temperature is above 7°C and there is available soil moisture. Late summer or early autumn sowing is often more successful than spring or early summer.

Mix the seed in the hopper immediately before sowing a seed mix to stop an uneven spread of crops in your plot.

Broadcast (scatter) seed or shallow drill no deeper than 1cm. Small seeds struggle to germinate when sown deeper than 1cm.

Roll after sowing to retain moisture, ensure good seed-to-soil contact and reduce slug damage. Do not roll where there is a risk of ‘capping’ (running rainwater causing the surface to form an impenetrable cap)..

Over-sowing herbal leys

Over-sowing is cheaper and uses less machinery, but is less reliable than sowing into a weed-free seedbed.

For best results follow these steps:

Cut or graze the existing sward very short.
Harrow to create at least 50% bare ground (aim for 70% to increase your chance of success).
Broadcast or shallow drill seed no deeper than 1cm.
Roll or tread in seed with livestock.
Remove livestock no more 5 days later, to stop damage to new seedlings.

Under-sowing herbal leys

You can under-sow into the arable crop before the ley. You’ll need to:

lower the seed rate of the arable crop
avoid any herbicide which will damage the plants in the herbal ley

How to maintain herbal leys

You can maintain herbal leys by:

grazing
cutting
grazing and cutting

Rest your herbal leys from cutting and grazing for at least 5 weeks in the summer. This allows flowers to open and provide a source of pollen and nectar for insects. You can shut up leys at different times to extend the time that pollen and nectar is available.

Rest periods allow plant species to last longer. Livestock that you allow to graze continuously will kill some species in leys, like legumes.

You do not need to use any nitrogen fertiliser on herbal leys. Fertiliser can cause grass to outgrow, smother and kill legumes and herbs.

You can use spot sprayers or weed wipers to manage injurious weeds.

Grazing herbal leys

Lightly graze your herbal ley in the first year after sowing. Light grazing controls annual weeds and encourages plants to bush out.

After the first year, rotational grazing with rest periods is the best ways to manage herbal leys. When grazing this way, you should:

start grazing after a rest period when the ley is around 0.5 metres to 1 metre high
graze until the vegetation height is halved
move livestock regularly to graze new areas of the ley and stop overgrazing
give enough time for the ley to recover between grazing periods
be careful not to overgraze - make sure vegetation is at least 8cm tall through the growing season

Cutting herbal leys

Cut as needed in the first year after sowing to control annual weeds and encourage plants to bush out.

You can cut and bale herbal leys for silage or hay.

How long to keep herbal leys

Keep herbal leys for at least 2 years.

It can take up to 4 years for the roots to grow enough to improve soil structure and fertility.

What a good herbal ley looks like

You should see:

an even spread of sown grasses, legumes and herbs across the ley
legumes and herbs for the entire life of the ley
open flowers during rest periods in each summer
a variety of feeding pollinators
no bare ground and few weeds in an established ley
vigorous growth providing high quality and nutritious forage for livestock
improved soil fertility after the ley has been removed

Create and maintain herbal leys

The guidance on this page is for SFI pilot participants only. Please visit GOV.UK for the official Sustainable Farming Incentive scheme guidance.