Trial reveals unexpected bonus of going peat-free

A WRAP trial of a peat-free growing medium containing green compost did not produce excellent growing results but positive outcomes still emerged, according to trial supervisor Arnie Rainbow.

The trial report stated that while many subjects in a peat-free mix grew slowly and had reduced root vigour, they had reduced liverwort growth, needing less controlled-release fertiliser and less firming in at the potting stage.

The trial compared a peat-free medium, consisting of 33 per cent green compost, 67 per cent conifer bark and a slow-release nitrogen fertiliser, with a standard peat-based medium supplied by Scotts.

It was conducted at Darby Nursery Stock in Thetford and set up by Rainbow of Rainbow Wilson Associates, with assessments by Abi Rayment of Dove Associates.

Ten genera were used in the trial, chosen from a range of protected and outdoor crops (Clematis, Cytisus, Dianthus, Euonymus, Lavandula, Potentilla, Pyracantha, Salvia, Sidalcea and Vinca).

The report found the following:

- Vigour was lower in the green medium in seven out of 10 crops, especially Cytisus, Lavandula and Clematis, but the herbaceous crops and Pyracantha performed well;

- Liverwort was much more evident on the standard peat medium, especially on Clematis;

- The naturally occurring nutrients in green compost are slow-release, so controlled-release fertiliser rates could be reduced by around 20-25 per cent - saving 1p/3-litre pot.

The report concluded that the exposed conditions at Darby Nursery Stock on capillary sand beds could have contributed to the concentration of nutrients in the pots and therefore the retarding of growth of salt-sensitive subjects.

Rainbow said: "The suppression of liverwort growth, over which there is no legal chemical control for nursery stock growers, could be a huge benefit as it could save the 10p per pot that needs to be spent removing it by hand.

"The handling of the peat-free mix through the potting machine was also very successful."

- A summary of the report is available at Fact_sheet_-_Darby_Nursery_Stock.1fff47e4.5839.pdf.

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Sign up now
Already registered?
Sign in

Read These Next

How big are the UK and Europe's apple and pear harvests likely to be?

How big are the UK and Europe's apple and pear harvests likely to be?

After a sizeable dip last year, Europe's apple harvest looks to be back on track, and could even break recent records. But the wider global situation means it should find a ready market.

What is the future for glyphosate?

What is the future for glyphosate?

The horticulture industry has defended glyphosate after a landmark US court case saw chemical company Monsanto ordered to pay $289m (£226m) damages to a groundskeeper who claimed herbicides containing glyphosate had caused his cancer.

Should more be done to address farm thefts and other crimes?

Should more be done to address farm thefts and other crimes?

The cost of vehicle thefts from farms is rising, while trust in the police's ability to deal with rural crime is in decline, two new reports show.

Follow us on:
  • Facebook
  • LinkedIn
  • Twitter
  • Google +

Horticulture Week Top UK FRUIT PRODUCERS

See our exclusive RANKING of UK Fruit Producers by annual turnover plus the FULL REPORT AND ANALYSIS.

Horticulture Jobs
More Horticulture Jobs

Pest & Disease Tracker bulletin 

The latest pest and disease alerts, how to treat them, plus EAMU updates, sent direct to your inbox.

Sign up here

Professor Geoffrey Dixon

GreenGene International chair Geoff Dixon on the business of fresh produce production

Read Professor Geoffrey Dixon