Flowering seed mixes and margin management

This page shows you how to choose and prepare farmland sites for flowering seed mixes and how to maintain them sustainably.

Flowering seed mixes are typically sown along field edges, but they can also be useful for filling in unproductive or awkward areas of land. Follow our five steps to successfully planning and managing flowering seed mixes on farmland.

It’s best to sow flowering seed mixes in nutrient-poor soil, where they have a competitive advantage over undesirable weed species and grasses. If that’s not possible, you can take steps to reduce soil fertility and limit weed issues before sowing.

One method is to sow a quick-growing, non-leguminous green manure crop, such as Phacelia or buckwheat, then mow it and clear the cuttings. Soil fertility should reduce with each ‘sow and mow’ cycle. Avoid north- and east-facing sites.

If you only have high-nutrient seed beds for planting, note that the site might need more management after sowing, to make sure the seeds establish properly.

Further research is needed on recommended sizes for sown areas, but the Ecostac project demonstrated that flower margins of 65 m long by 2 m wide already demonstrated clear benefits.

To clear a site for sowing, use the ‘stale seedbed technique’, where possible. Prepare the seedbed by clearing the selected area, then allowing a flush of weed seed germination. Resulting weeds can then be cleared to produce a cleaned ‘stale’ seedbed, which should have a reduced weed seed burden.

Soil should be cultivated to sufficient depth to alleviate compaction and bury any trash present. The seedbed should then be raked or harrowed and rolled to produce a fairly fine, firm surface. As a guide, the finished seedbed should be firm enough to walk on without leaving impressions.

• Seed mixes should be sown evenly onto the prepared soil surface by hand-broadcasting, seed fiddle, seed/fertiliser distributor, hydra-seeding, or any other suitable recommended method
• Bulking the seed mix with an inert carrier such as sand can help you achieve even distribution
• Seed may also be drilled, but most wildflower seeds are very fine and cannot germinate if buried, so drills must be set as shallow as possible (maximum depth of 7 mm)
• If seed has been hand-broadcast, beds may benefit from light raking after sowing, to make sure seed is even – take care not to bury it
• After sowing, beds should be rolled or tread, particularly in dry weather and with freshly worked loose soil. This presses the seeds into contact with the soil, brings moisture to the surface, and maximises germination rates

Seeds should generally be sown in either autumn (August–September) or spring (March–April). However, timing is weather-dependent and may be dictated by specified sowing dates for agri-environment schemes.

Try to sow in warm and moist conditions, while remembering that the seeds of some flowering species (such as yellow rattle) need a period of cold weather to germinate.

You will need to manage your sown areas, particularly in the early years when using a perennial, non-rotational seed mix. Keep on top of aftercare to restrict grass or weeds from taking over.

Aftercare is key to ensuring that a diverse stand develops (left), otherwise grasses may dominate (right). Image copyright Dr David George, STC.

In the absence of grazing, mowing is the main way to manage grass species and some weed species. You can consider herbicides for weeds, but if mixes are included in agri-environment schemes and/or Environmentally Focused Areas (EFA), check which products you’re allowed to use.

Mow the sward to around 10 cm and remove cuttings to keep soil fertility low. ‘Blanket mowing’ is not recommended for flowers that are being regularly used by beneficial insects. Note that certain agri-environment scheme options also require a percentage of the plot to be left unmown over winter to provide undisturbed habitat.

Instead, use staggered mowing to cut some areas and leave others rich in flowers for beneficial insects. This also allows you to vary the sward height, which can be helpful for beneficial invertebrates and some farmland birds.

Selected flower-based agri-environment scheme options (2015) with their respective establishment and management guidelines

Information obtained from gov.uk/countryside-stewardship-grants