A growing choice - the industry assesses alternatives to peat

Industry efforts to reduce peat continue as coir suppliers invest in continuous supply and growers take part in trials to assess alternatives, Gavin McEwan reports.

Balasuriya: Botanicoir to open million-pound drying facility in Sri Lanka next month - image: Botanicoir
Balasuriya: Botanicoir to open million-pound drying facility in Sri Lanka next month - image: Botanicoir

Coir has become a staple growing medium for some areas of fresh produce in recent years. But as the industry has grown more reliant on the coconut by-product, consistent supplies have been threatened by changing weather patterns in the Indian Ocean area, from where most of it is supplied.

In response, Botanicoir will open a million-pound purpose-designed drying facility in Sri Lanka next month to ensure consistent year-round supply, in what the company says is an industry first.

"Both last year and the year before were very wet in Sri Lanka," explains managing director Kalum Balasuriya. "We were able to fulfil our orders with UK customers, though with some extension on deliveries, and there is a limit on their flexibility. We had to ship some undried bags at three times the volume and we took a hit on that. So there was a need to move into machine drying to safeguard our commitment to growers and the growth of our business."

Consistent supply

Botanicoir took the proposal to a German engineering company two years ago. "They had to research and develop this for us. Coir particles are sensitive to high heat - it can destroy the honeycomb structure. This mimics the traditional way it's dried, but more reliably, giving us a continuous supply that is consistent in moisture levels," he points out.

The result of 12 months of dedicated research and development, the facility will dry the coir as it passes along a conveyor, with heat controlled by a number of sensors and adjusted to suit the coir's moisture level. The automated machine will only require one person to control it. Powered by woodchip biomass boilers "in line with our sustainability aims", it will produce around 80 per cent of Botanicoir's raw material output. "The other 20 per cent will come from existing natural drying yards," says Balasuriya.

"This means that in a good year we'll have the ability to produce 80 per cent more product than before we had the dryer. With a 30 per cent rise in orders this year, demand is growing at a phenomenal rate, so we need this development."

Sri Lanka, the world's largest exporter of coir fibre-based products, normally has a monsoon season. But unprecedented year-round rainfall over the past two years has affected the whole coir industry because coir pith is usually dried by sunlight.

Pressure on peat use

Despite the rise of coir and other alternative growing media, the production horticulture industry remains under political and consumer pressure to move away from peat - a task that has proved easier in some areas of production than others.

To address this, "Transition to Responsibly Sourced Growing Media Use within UK Horticulture" is a five-year, AHDB Horticulture and Defra-funded research programme bringing together researchers, growers and suppliers.

Speaking at the recent British Herb Trade Association field day, ADAS horticulture consultant and manager of the project Chloe Whiteside explained: "We aim for a predictive model. Last year was spent assembling four raw materials - coir, wood fibre, bark and green waste - into 75 blends." These are being tested for their physical and chemical properties, yielding a 3D model of their air-filled porosity, available water and dry bulk density.

"We are testing the theory of the model in trials at ADAS Boxworth and Stockbridge Technology Centre," she added. "We have selected three blends that the model says 'should' work as well as peat, as well as two that 'shouldn't'."

These are being used to grow coriander, chives and thyme as well as hardy nursery stock, bedding plants and apple and cherry trees for propagation. "This will give us baseline data for when we test the blends at commercial growers. We have already tested peat-reduced and peat-free mixes against growers' own products, which has given us a baseline and a model for future trials. Growers find they may need an extra day to get plants up to spec but haven't otherwise had to do anything very different."

Vitacress is growing pot herbs, G's Growers is trialling lettuce propagation blocks and New Farm Produce is doing strawberries. Next year Lincolnshire Herbs will carry out further herb trials, EU Plants will look at soft-fruit plant propagation, Frank P Matthews will work on top-fruit tree propagation and G's will cover mushroom growing.

"There will be different solutions for different crops," said Whiteside. "For the whole industry to go peat-free by 2020 is unlikely but we need to show that as an industry we are at least trying to reduce peat use - and show that to customers as well."

Significant UK market

Blocking compost has been an area of production horticulture in which peat alternatives have made fewest inroads so far. This is no small market. The UK's largest supplier, ICL, estimates the market for blocking compost in the UK to be around 80,000cu m - enough to fill 30 Olympic swimming pools.

"While trials have been carried out over the last decade using reduced-peat ingredients, such as bark and coir, the plant raiser market prefers the 100 per cent peat product for consistent performance, wetting up and blockability," according to ICL sales and business development manager Shaun Cavanagh.

"The majority of the blocks produced for outdoor planted crops are 3.2cm blocks," he explains. "This is the best compromise for reducing costs while maintaining quality of plants and flexibility of planting in the varied conditions growers face in the field. Conversely, winter indoor crops have moved to bigger blocks - many 6cm - to minimise time in the protected cropping house, so keeping heating costs to a minimum."

A small volume of blocking compost is used in vegetable plant propagation, but this market uses 99 per cent modules rather than blocked plants because vegetable plants lose less water than salads through their leaves. "Previous generations of salad producers used to sow direct into the fields, but the crop took too long to reach harvest and required more labour to thin out to viable density cropping."


GrowCoon: culture plug keeps the root ball together

Cutting-edge products for growing media unveiled at the GreenTech trade show in the Netherlands

This summer's GreenTech in Amsterdam brought forth a range of innovations in and around growing media for protected horticulture. Nominated for the GreenTech Community Innovation Award, the GrowCoon by Maan Biobased is a net-like culture plug made from Degrasive, a fully biodegradable polymer, that can be placed in a tray before it is filled with substrate. It keeps the root ball together at later transplantation, before breaking down completely in the soil. Available in a wide range of customisable sizes and in either cylindrical or conical shapes, it can be used in any tray or substrate and can be supplied separately or pre-inserted in trays.

An innovation in the plug substrate itself, Jiffy's FORMiT has been developed to cope with automated handling and transplanting even of smaller plug sizes. Containing a mineral to bind the substrate once water is added, FORMiT mixes "are an ideal solution for veggie growers who produce young plants in a smaller plug, making use of automatic planting equipment", says the company. FORMiT was named new product of the year at the Cultivate '16 trade show in Ohio, USA, in July.

In coir, Dutch specialist Collab says it has introduced a more sustainable way of buffering, a process usually carried out at the coir factory using an "unnecessarily enormous" amount of up to 11kg of buffer agent per cubic metre of coir, causing run-off that ends up in surface water, groundwater and soils. By contrast, its MORE Coco Buffer Dose Unit uses up to 80 per cent less buffer agent and reduces water use by 30 per cent. "As a result you obtain coir that meets generally accepted quality standards while saving costs, natural resources and preventing water and soil contamination," says Collab, adding that it becomes "financially feasible" from an annual consumption of 1,000cu m of coir and was developed with Apollo Coco Debaler.

For stone wool growing, supplier Cultilene has launched the SympHO2ny pH meter that provides a real-time view of the pH dynamics in the root environment, enabling rapid adjustments to optimise cropping. Innovation manager Henri Beekers describes it as "very much like a stethoscope for the plant". He adds: "Most growers only measure the pH level in the root environment once a week or once a fortnight. This can be a cumbersome process - they must send a water sample to a laboratory and it usually takes at least 24 hours before the result is known."

Carbomat of Poland presented a novel growing medium derived from lignite, or brown coal, that it claims is "an excellent alternative to mineral wool" with the necessary porosity and water absorption combined with low salinity and chemical stability, making it easily controllable. Enriched with humic acid, the substrate can be used for cultivation over several seasons, after which it can be used as a soil improver or outdoor growing medium.

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