What is hydro-seeding?
Hydro-seeding is the process of spraying a mixture of water, seed, mulch (and sometimes fertilisers) onto the ground at high pressure (usually from a hose attached to a pump). The mulch makes the seed stick to the ground and retains moisture to help the seed to germinate. The mulch also disguises the seed from birds who might otherwise eat it. Hydro-seeding of grass seed is commonly used in subdivision and roading projects and can be very effective for planting hillsides and steep slopes, where conventional planting by hand would be difficult or expensive, to control or prevent erosion and support greater biodiversity than would be possible with bare, eroded land.
What was the purpose of the Living Water trial of hydro-seeding?
Living Water trialled direct hydroseeding of native sedge seeds at trial sites next to Lake Ruatuna in the Peat Lakes catchment in Waikato, to determine if it could be a successful and cost effective restoration approach compared to conventional planting. Two trials took place. The first was on steep ground directly adjacent to the lake, and the second was on a farm by a waterway, though not on steep slopes.
Who could use hydro-seeding?
Landowners with steep-sided waterways, regional and district councils and catchment groups.
Hydroseeding trial at Waikato Peat Lake, May 2018
How does hydro-seeding work?
Planting the edges of waterways with low lying native vegetation is a well-known and beneficial technique used to stabilise banks, prevent erosion and run-off entering the water, shade the water to improve the freshwater eco-system and enable fish and invertebrates to flourish, and reduce nuisance weed growth. Waterway banks are often steep, making them difficult to plant and to maintain. Hydro-seeding may provide a cost-effective and practical solution to planting steep-sided waterways delivering all the benefits of conventional planting at locations which otherwise couldn’t be restored or enhanced. In New Zealand, organisations such as Waka Kotahi (NZ Transport Agency) use hydro-seeding successfully to plant up cuttings and embankments around motorways and expressways. Hydro-seeding has been in use globally since the second world war.
What did Living Water learn from the trial of hydro-seeding?
The first trial in 2017 was not successful due to non-viable seed. This trial was repeated in 2018, where sedges germinated at a density of around one plant per square metre. The second trial in 2019 at a different site near a farm drain/waterway (not on the steep slopes) was unsuccessful due to drought conditions preventing plants from establishing. The sensitively of hydro-seeding to issues with seed viability and rainfall / drought led to Living Water’s decision not to conduct further trials of hydro-seeding.
Where is more information available about hydro-seeding?
DairyNZ full report will be available soon