Hay-strewing involves the use of hay from local semi-natural grasslands which contain the seed of desirable native broadleaved herbs and grasses. As with natural recolonisation, it provides a locally appropriate indigenous seed source. Suitable donor semi-natural grasslands can be located through consultation with one or a number of the following: local landowners, farmers, Teagasc, the County botanical recorder for the Botanical Society for the British Isles and/or the National Parks and Wildlife Service.
The harvesting of hay from a donor grassland will require landowner consent/written permission. If the source grassland is within or adjoining a designated protected area, statutory consent from NPWS will be required.
Hay is cut by a silage harvester and is baled in late August/September while still slightly green, i.e. just before the seeds have dropped. This hay will provide the greatest species diversity and number of seeds.
Hay from the source grassland is spread loosely onto the area to be treated and in the following spring the seed germinates under the protection of the hay covering. In this regard small square bales are much easier to handle and to break open and spread than large round bales. The bales must be broken up and spread immediately to avoid seed losses due to decomposition of the damp hay.
For smaller areas hay can also be cut by hand and piled on top of a tarpaulin and transferred by trailer to the recipient site.
In wet areas where Wet Grassland (GS4) habitat is present, it may be difficult for machinery to access the donor meadow. In addition machinery may cause disturbance to the meadow. In this regard, hand picking of seed heads or hand cutting of the hay containing the seed may be the only options.