A Brief Guide to the Green Hay Technique
The green hay technique is a method of introducing hay meadow plants to meadows that have lost, or never had, the diversity of plants that occur in good, species-rich meadows. It is generally considered better than the alternatives of sowing wildflower seed or planting plug-plants.
The trickiest aspects of the operation (excluding the weather!) are co-ordinating cutting of recipient and donor sites, and ensuring the green hay is strewn as quickly as possible.
Step 1: Assess the recipient site
It is crucial to try to match donor and recipient sites in terms of its soil, altitude, existing management etc. to maximise the chances of success. It is also important to survey the existing plants as they may have their own conservation value.
Step 2: Identify a suitable donor site
The donor site should match the recipient site as closely as possible. This should ensure that the plants growing in the donor site have a good chance of surviving, and flourishing, on the recipient site.
Step 3: Prepare the recipient site
Once hay has been cut and removed the site needs to be reduced to bare earth as much as possible. Very small sites could be raked by hand, but fields will need to be harrowed.
Step 5: Cut grass on donor site before seeds drop
As the idea is that the seeds will fall out on the recipient site the donor site must be cut before the seeds fall out there.
Step 6: Transport green hay immediately
Seeds may also drop out as the cut grass at the donor site starts to dry, so it is important to collect up the cut grass while the hay is still fresh (hence green hay). However, piles (or round bales) of cut grass can generate enough heat through fermentation to kill seeds, so the hay must reach the recipient site as quickly as possible.
Step 7: Disperse the green hay evenly over the recipient site
The green hay can be strewn by hand, or if the green hay has been round-baled it can be spread initially by unrolling the bale. The green hay should be spread thinly – the suggested rate is to cover three times the area from which the green hay was taken
Step 8: Use a roller or livestock to trample the seed
Good contact with the soil is essential for good seed germination. This can be achieved by rolling or by using livestock to trample the seed.
Step 9: Monitor the recipient site
Although not essential, it is useful to monitor the recipient site to gauge success. Note that it may take several years for some plant species to appear.