BRING OUT YOUR DEAD!

UCD horticulturists Zoe Valentine and Noeleen Smyth share their views on some alternatives to peat compost – and a link between coffins and sustainable materials.

As many in horticulture are aware, the cessation of large-scale peat harvesting is forcing the industry to explore alternative materials as growing media, such as coir (coconut fibre), wood fibre, and composted bark.

Estimates of current use highlight that over 50 per cent of the Irish horticultural sector is still reliant on peat; hence the cessation of supply is having a major impact.

A survey of growers was carried out by UCD horticulture student Zoe Valentine, at the Irish Hardy Nursery Stock Association trade show at Whites Agri Premises in Lusk, Co Dublin, on 21 February 2023.

According to the survey, wood fibre was the most popular alternative material to peat, with over 50 per cent usage in the sector among the growers surveyed. Four out of eight companies solely use wood fibre as an alternative material.

All those surveyed agreed that one of the impacts of switching to peat alternatives is the high cost and limited availability of the substitute materials.

But peat is also rising in cost: one of the growers reported an almost doubling in production costs associated with peat compost in one year. The cost of peat for one participant surveyed grew from €140K in 2022 to €260K in 2023. Growers are being forced to switch to alternative materials as a matter of both economic and environmental urgency.

The Quest For Peat Compost Replacements

One clearly observed negative effect of growing in wood fibre and barkdominated composts is water regulation. Herbaceous plants in particular suffer in the drier conditions of bark-dominated composts, and are often seen wilting and drying, as bark and wood fibre composts struggle to retain any moisture and are extremely prone to drying out.

With the race on to find suitable compost alternatives, Teagasc’s Ashtown Food Research Centre in Dublin 15 have been carrying out some impressive largescale trials using various ratios of coir, wood fibre and peat.

WHAT ARE SUSTAINABLE ALTERNATIVES TO PEAT?

The Revolution Farm & Kitchen, a saucemaking and mushroom-growing business project based on campus at University College Dublin, uses various compost mixes that contain bark shavings and spent coffee grounds. They also grow their mushrooms in wheelie-bins.

Inspired by the projects at Teagasc Ashtown and Revolution Farm, Zoe carried out an experiment to build a novel compost using only locally-sourced materials which are widely available.

The first material Zoe selected was oak bark shavings, a renewable resource rich in carbon and organic matter. The oak shavings used for the experiment were re-purposed from the spent mushroom composts of Revolution Farm & Kitchen.

Oak is a fairly high-end timber material, but the oak bark shavings Zoe used are a byproduct of an industry that we’ll all have to avail of eventually – the funeral industry. Many coffin manufacturers in Ireland use oak.

The second material Zoe picked

T e a g a s c C o l l e g e o f A m e n i t y H o r t i c u l t u r e

Situated in the National Botanic Gardens, Glasnevin, the Teagasc College of Amenity Horticulture offers a wide range of training courses

This wonderful location provides our students with a unique training experience; blending the finest park setting in the Capital with the invaluable experience of OPW staff of the gardens and the Teagasc College faculty All students can avail of work experience in the Botanic Gardens as well as in parks & gardens around the city and other placements further afield

Graduates of the college are leaders in the field of Horticulture and develop clear career pathways Careers in landscape design and construction, garden & parks, garden centres & plant nurseries and organic food production are all followed by our graduates

QQI Level 5 Certificate in Horticulture

QQI Level 5 Component Certificate

QQI Level 6 Advanced Certificate specialist streams: Sports Turf Food Production

Landscaping

Nursery Stock Production

QQI Level 6 Component Certificate scan here to see all of our courses

BOTANIC COLLEGE@TEAGASC IE 01 804 02 01