Growing media - market progress

Peat shortages have created market opportunities for alternative growing media such as coir, Gavin McEwan reports.

 Renewable energy sources that are used overseas help to offset carbon footprint of sea transport of coir - image: Fotokannan
Renewable energy sources that are used overseas help to offset carbon footprint of sea transport of coir - image: Fotokannan

Times are tough for peat, as suppliers cope with what one calls a "dire" season. Harvests are down around 70 per cent and prices for what stocks are available are up 20 per cent.

Meanwhile, the Government ruled last month that one of the largest harvesters, William Sinclair Horticulture, can no longer extract peat from a large site in Greater Manchester, citing environmental concerns.

"The peat shortage means a greater role for supplements like coir and bark, but also price inflation no matter what the mix," says Jim McAlpine, managing director at trade supplier Fargro. "The multiples want to reduce peat anyway. Growers are simply interested in a product that works and judge non-peat mixes on that basis."

In fresh produce, he adds: "Coir companies are making inroads in tomatoes and cucumbers — the level of competition tends to make it cheaper and it has dropped in price. The situation here is quite different to Holland, where they mostly still grow stone wool. Coir is also replacing peat in soft fruit, and I can’t see the industry going back on that."

Coir has already been the main beneficiary of the trend away from growing soft fruit in soil to growing in raised structures, says Horticultural Coir managing director Tom de Vesci. "We are very busy these days — our turnover has more than doubled over the past couple of years. That’s partly due to the shortage of peat this year, but also to the trend for alternatives. Most of the big companies now also use coir."

Economic decision

For strawberries in particular, coir is now the growing medium of choice on economic grounds, says de Vesci. "It doesn’t degrade as quickly as peat, where the nutrients break down the structure fairly rapidly. Coir, which holds its structure better, can be used for two seasons rather than one."

Another cost factor is transport, he adds. "All transport is going up, but peat is 50-60 per cent moisture. We encourage growers to buy coir in dry, compact form — ‘planks’ — that then fill up the bags when irrigated." But he cautions: "If you’re on a windy site, the bags may get blown away before they’ve expanded."

Coir’s progress in the market has not always been smooth though. "Quality was a problem in the early days," says de Vesci. "Salt content was the biggest question and particle size wasn’t given enough attention — inexperienced people selling a product they didn’t understand. Growers should still be wary of companies that haven’t been around long."

A member of the industry’s Growing Media Association, he adds: "Members generally agree there is too much reliance on peat and this year has shown the weakness of that. There are no big divisions. We are all doing business with each other. But peat suppliers are now less able to pay for the alternative media, so we are not rubbing our hands. When conditions are tough, we don’t want to pass increased prices onto growers."

Cocogreen sales manager Thomas Ogden says the Government’s "looming" targets to phase out the use of horticultural peat altogether "are good for us and other coir producers". But coir is making headway in other markets where peat is not an issue, he adds. "Still a majority of protected salad uses stone wool, but the switch to coir is increasing. We’re taking more market share every year."

But like de Vesci he urges caution in sourcing coir. "Unlike stone wool and peat, it’s still a developing medium. There are several coir suppliers and some come and go each year." Unlike those, he says: "We have full traceability and can guarantee quality as we have control over the whole supply chain. If you’re using middle men, you run the risk of late or inconsistent deliveries. Growers also expect technical support from their supplier, which we offer free of charge."

One criticism levelled at coir is over its sustainability and the possible future limits to supply. But Ogden says: "We are forward-thinking on supply and are looking outside of Sri Lanka too. Others may find they hit a wall."

The ethics of the trade have also been called into question, he acknowledges. "Growers are undergoing environmental and ethical audits, and those auditors want to see documentary evidence, particularly on treatment of staff. India has ethical issues around labour but where we source from in Sri Lanka doesn’t," he maintains. "This is also an issue for the peat suppliers."

Green credentials

On the environmental issue, Ogden adds:

"Turning basalt into stone wool takes a huge amount of energy, then yet more energy to turn it into bricks — it easily outweighs the carbon footprint of sea transport. And the energy we use in Sri Lanka comes from renewable sources, so it’s carbon-neutral at that end."

Coir can be disposed of locally at little cost, he points out.

"One large protected salad grower has invested in further processing to turn coir into a Soil Association-approved organic compost for next year’s organic crop. Other growers are selling it to local farmers as a soil conditioner, or it gets turned into a low-end growing media for blending."

However, Grodan, which supplies the market-leading Rockwool medium, has recently been emphasising the environmental credentials of its stone wool product, launching a video on sustainable growing earlier this year.

"We want to take our responsibility in helping growers and other partners in the sector explain to stakeholders further down the value chain what sustainable growing entails nowadays," says marketing director Vincent Deenen.

The Dutch-based manufacturer has recycling partners in each country where it supplies that process the spent slabs into a form that can be made into building bricks. Dutch partner Van Vliet Contrans collects 120,000cu m each year — enough to fill the Royal Albert Hall with plenty to spare.

However, one area of edible horticulture in which peat still predominates is leafy salads. "It’s not just the ones growing a finished product under glass. Outdoor salads are also raised in peat," says British Leafy Salads Association chairman Colin Bloomfield. "The range of uses is quite wide."

Some leafy salads such as those grown for supermarkets’ living salads ranges are sold still in a peat block, though others are also grown in blends. However, he points out:

"Peat has particular characteristics, mainly that it holds together when handled in a way that coir doesn’t. Especially when you are machine planting, you need something that’s quite robust.

"It will also keep the young plants upright during their first 48 hours in the soil, until they begin to establish. There are technical requirements for the job and right now we don’t have an alternative to peat that does all these things." However brassica growers, having less exacting requirements here, "have moved away from peat", Bloomfield adds.

While these needs may be less pressing for baby leaves and living salads, "peat has low levels of bacterial contamination and high water-holding capacity through the chain," he says.

"The major propagators and their suppliers have been looking at peat alternatives, but in 10 years no one has come up with something that has all its properties."

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