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Brush Harvesting For Biodiversity

Funding for the Cranborne Chase cluster is enabling more biodiversity-sensitive farming techniques...

DEFRA FiPl Funding obtained by Facilitator Clare Buckerfield and the Cranborne Chase Farmer Cluster, UK, has brought onboard a brush harvester - for biodiversity-sensitive management of grassland.

The cluster's brush harvester | © FWAG
The cluster's brush harvester | © FWAG

What Is Brush Harvesting?

Brush harvesters collect seed but don't cut the grass, so the hay can be cut afterwards. Some small loss of hay quality may occur if the normal hay-cut is delayed. Landowners are normally paid a premium to compensate for this.

The meadow to be harvested will normally be ready in mid-July (southern

central England) or late July-early August (upland Britain). This is when the main grasses, such as Crested Dog's-tail and Meadow Foxtail hold ripe seed and the Hay Rattle seed is still on the plants.

The seed mixture that's collected includes the seed of those plants which hold ripe seed at the time of harvesting. "Missed" species sometimes include Ladies Bedstraw, Devil's-bit Scabious and Meadowsweet as well as some early-flowering plants.

Summarised from a Chartered Institute of Ecology and Environmental Management resource at

The cluster's brush harvester in action
The cluster's brush harvester in action | © FWAG

How Does It Benefit Biodiversity?

Brush harvesting can be used to restore or maintain species-rich grassland.

Grassland with wildflowers and good biodiversity is vital to support overall farmland biodiversity, including important ecosystem services like pollination, soil and water management and pest bio-control.

Brush-harvested seed can also be taken from a species-rich donor site and spread on a species-poor recipient site to restore and recreate wild flower grasslands.

Good seed sources need to be found and swept for seed throughout the growing season so that early and late flowering plants can be collected. It can be a relatively cheap method compared with buying seed mixtures, but the availability of brush-harvested seed may be limited.

Find out more via this Magnificent Meadows resource:

Or watch our Biodiversity Bases Twitter video to discover how wildflowers support farmland ecosystem services:

How Does It Work?

Brush-harvesting is a fair-weather operation to be carried out in dry weather, and once the morning dew has evaporated.

The harvester is towed across the site and seed is brushed into a hopper; the seed is emptied onto tarpaulins when the hopper is full (about every 20 minutes).

If it is not to be down directly, the seed is spread out to dry and raked through during the day to help it to dry. Long stalks are also raked out. The seed can be dried outside if the weather is fine, but may need to be taken inside and dried in well-ventilated barns if rain is threatened.

It can take between two and seven days to dry, and must be regularly raked through to prevent it becoming mouldy. If the seed from a day's harvesting has to be transported any distance, it should not be kept "en masse" for more than a few hours until it is dry, as it will heat up and the seed will become unviable.

The seed yield will vary from site to site, from field to field and within fields. It can also vary from year to year on the same site. A yield of between 10kg25kg per acre is considered a low-average yield.

#1 close-up of the cluster's brush harvester
#1 close-up of the cluster's brush harvester | © FWAG

Once dry it can be stored, then cleaned using a combine or seed cleaner to remove most of the stalky material and husks. It is best broadcast using a spinner (Zircon or Vicon type). If the seed is well-cleaned it may be possible to drill it, e.g. using a corn drill with the spouts removed. Seed of wild flora should always be drilled or broadcast on the soil surface and never buried at any depth.

Unprocessed seed can be directly sown by bagging it up straight from the hopper or tarpaulin and taking it across to the receptor site, where it can be broadcast by hand from the back of a trailer or pickup. (It will not pass through a spinner.) Due care should be taken for health and safety.

Summarised from a Chartered Institute of Ecology and Environmental Management resource at

#2 close-up of the cluster's brush harvester
#2 close-up of the cluster's brush harvester | © FWAG


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