The creation of grassland, whether that be calcareous, acid or lowland meadows post-extraction is often through the use of commercial seed. However, an alternative option is the use of ‘green hay’ from a local suitable donor site which can often lead to a sward with better productivity and species diversity than if sown with a commercially-bought seed.
What is Green Hay?
‘Herbage cut at or just before the hay stage, which is collected immediately without prior wilting or turning.'
Green Hay Benefits:
- Increased species diversity
- Species of local provenance, thus maintaining local genetic diversity
- Lower cost than commercially-bought seed
5 easy steps to creating species rich grassland through green hay:
1. Identify a suitable donor site
- Ideally in the same locality;
- With similar site characteristics (for example soil type, pH and hydrology);
- Free from ruderal weed species (for example spear thistle, common nettle, broad-leaved dock);
- Dominant species including Yorkshire fog, white clover and creeping buttercup, must not dominate the sward;
- Be of a suitable size (1 acre of green hay will cover approximately 2-3 acres on the receptor site); and
- Ensure it is physically possible to harvest the hay.
- Ensure that harvesting the hay would not disturb the faunal interest at the site, for example ground nesting birds.
2. Timing of green hay collection
- To allow the plants to flower and set seed, the sward must be left ungrazed / uncut for 8- 12 weeks prior to collection
- Traditionally managed hay meadows – mid July to early August
- If targeting particular late-flowering species, a later cut maybe preferable – late August to early September.
- Cut green hay must be collected within 24hours of cutting
3. Prepare the receptor site
There must be adequate bare ground to enable the seed to germinates and establish without being immediately outcompeted. Optimal conditions include:
- A short sward (either through cutting and removing arisings, or by grazing);
- Ruderal weeds (on site and in the vicinity) controlled through spot treatment of herbicide; and
50% bare ground (either through livestock or by machinery)
4. Spreading the hay
- Cut and collected material must be transported to the receptor site on the same day, and ideally within 1-2 hours.
- The hay must be spread evenly across the receptor area in a thin layer so that the sward beneath is still visible.
- Large areas – hay can be spread using a muck spreader or straw chopper
- Small areas – hay may need to be distributed by hand (can be used as a
community engagement exercise, using local volunteers).
5. Follow-up Management
- Following hay spreading the sward should be kept short to allow maximum light penetration to aid germination (July-Nov).
- Perennial weeds should be controlled early on through spot treatment with herbicide.
- It may be necessary to repeat the hay-spreading on mineral restoration sites, particularly
- if the donor site is not particularly species-rich.
Edwards et al. (2007) Hay strewing, brush harvesting of seed and soil disturbance as tools for the enhancement of botanical diversity in grasslands. Biological Conservation, 134, 372-382
Relevant case study
Natural England Technical Information Note TIN063: Sward enhancement: diversifying grassland by spreading species-rich green hay.
The information set out within this advisory sheet in no way constitutes legal or regulatory advice and is based on circumstances and facts as they existed at the time Nature After Minerals compiled this document. Should there be a change in circumstances or facts, then this may adversely affect any recommendations, opinions or findings contained within this document