Plants produced in pots that can either be left to break down in the soil or taken off and composted would seem an appealing option to customers. Not only is one of horticulture's big headaches - the disposal of waste plastic - removed, but the plant's carbon footprint is also cut.
So far though, these have made slow headway in mainstream production horticulture - partly down to cost and partly due to concerns over their performance in production and handling.
Not that they are exactly new. Norway-based Jiffy Products has been producing biodegradable peat-based pots for more than half a century. But UK sales and marketing manager Richard Stevenson says the environmental arguments are by no means clear-cut.
"Looking at the product's life cycle, how important is biodegradability for customers? What supermarkets are concerned about is carbon footprint - that's what they are publicising and where they have set targets. Initially that meant the big-ticket items such as vehicles and storage, but it's now getting into the product range too and retailers are putting pressure on growers to both declare and reduce their own carbon footprint," he says.
"We as an industry should look at alternatives. But if you compare the carbon footprint of our industry overall with that of other products, horticulture does not look so bad. And it's very difficult to get a true carbon footprint analysis." He adds that Jiffy's own range "hasn't changed a great deal", except that biodegradable pots can now be printed onto and composted afterwards.
Recent comparison trials in Germany have given a qualified thumbs-up to biodegradable pots in terms of their nursery performance. The State Teaching & Research Institute for Horticulture (LVG) in Heidelberg trialled eight different commercially available biodegradable pots alongside conventional plastic equivalents in crops of Petunia, Nemesia and Mandevilla this year.
It found "near-identical plant quality" in Petunia, but noted "some differences in the consistency of individual pots at point of sale". It also assessed the root development as being as good as in the control in Desch Plantpak's D-Grade Bio Ingeo and JD Transbio's Nature Pot, with pots from Jiffy, Groencreatie, Napac, Soparco and Poppelmann scoring only marginally lower.
The trials report noted some cracking, fungus growth and decay on several models and also pointed out that harder pots made from potato or maize starch were more robust in production, but only compostable at higher temperatures produced in industrial composting.
Desch is also among those pushing its biodegradable line hardest and has created a dedicated website for its D-Grade Bio range at d-grade.com. The company states that not only is the range certified compostable, it is also "completely free from genetically modified materials, and this is proven by means of a gene scan". This was found to be the least readily degradable in the ground at the LVG trails.
Unlike established pot and container companies, which are diversifying from mainstay conventional plastic product lines, JD Transbio of Lyon in France is a recent start-up focusing solely on biodegradable pots made from recycled potato peelings. The pots' design features two-level drainage holes and thin sections on the base to speed up decomposition in the ground.
The company has also calculated the pots' "ecological balance sheet" compared with conventional polyethylene pots, claiming its range produces 62.3 per cent less CO2 in its manufacture, and 78.1 per cent less in disposal.
Netherlands-based manufacturer Kreuwel Plastics also supplies pots made from potato starch, in 9cm and 13cm sizes. UK representative Nigel Swain says: "We have been developing a couple of formats - longevity of the product is an issue. These don't start to biodegrade until they've been in use for three or four years."
Swain's Square Root Horticulture also supplies conventional plastic pots from continental suppliers. "Recycled plastic pots are environmentally friendly and the percentage of recycled plastic in these is high," he says. "From the EU you have a lower carbon footprint compared with those made in China. It's debatable whether their pots are biodegradable. It will cost you two or three times more depending on the size."
He believes that increasing demand for environmentally friendly pots "has to come from the Government", adding: "We have had some orders, but on the small side, from clients with an environmental bent. There is added cost to environmentally-friendly products and the grower has to pass those on."
LVG Heidelberg also tested Swiss manufacturer Napac's NaturePots against a conventional equivalent growing of Primula in a cold glasshouse and polytunnel. "Previous trials have shown that dense planting combined with low temperatures and high humidity can cause an unwanted fungal growth on pots," the report states. But in this case significant fungal growth was found only on the pots in the warmer glasshouse. Plant quality and production time were comparable with the control in both cases, it adds.
In an effort to tick all the eco-boxes, Napac's pots are made from reed or rice fibre, set with natural binders also derived from plants and vegetables, all "primarily found in Europe in order to limit CO2 emissions", according to its UK distributer Soparco, which also markets its own Organic range of smaller, square cross-sectioned pots and matching trays made of wood fibre.
Sales manager Murielle Jayer says of the Napac range: "You can plant it with the pot if you break the pot first. It will then break down in the soil," while its Organic range is rigid enough to be handled by a de-stacking machine.
Already in use on the continent, both are new in the UK. "With these pots, most customers will try it on a small production run to see how it works," Jayer adds. "You have to educate customers. It's a long process."
By working together with pot supplier Poppelmann, German specialist grower Holz has developed a growing solution that benefits plants, minimises handling and creates a distinctive presence on retail benches.
The printed plastic plant pot in combination with the matching green transport tray adds to the distinctiveness of the Beauty Queens series of heathers, says owner Hans-Peter Holz.
"It has been my aim to accentuate novelties so that they are easily recognisable and the pot and the green transport tray are a significant part of the success," he adds.
Holz previously used a standard pot with a plain six-hole bottom, but has found improved results with the multi-hole profile bottom, inwardly arched, with irrigation holes on two levels.
The holes in the upper level do not have any contact to the ground and ensure a fast and direct water flow, while the lower bottom holes assure an effective capillary drainage.
NEW PRODUCT ROUND-UP
French supplier Soparco has introduced its Colorama range for pots, planters and hanging baskets. "They are good for garden centres, where they allow growers to differentiate their production," says Murielle Jayer. "We can create new colours and there's no minimum quantity."
The Poppelmann hanging basket with irrigation holes on three different levels has a clip-on saucer, while the pot lips are designed for automated de-stocking. They come with different sizes of hooks depending on the pipe from which they will hang.
Essex-based manufacturer H Smith has launched a clear plastic lid for its half-tray and cell pack range, which can be used either for packs of ready-grown plants at retail or to allow home gardeners to propagate their own on a windowsill.
South Yorkshire-based Containerwise Materials Handling has launched a 216-plug tray made of UV-stabilised recyclable polypropylene aimed at the young vegetable plant market. Anti-spiral root ribs prevent ball rooting.