Making the valley greener

The bioplastic is better to work with than regular plastic as it is more elastic and does not tear as easily.

Constantia Glen wine estate has broken new ground by testing an alternative to plastic for mulch.

When Constantia businessman Andrew Pollack found micro-plastic in his borehole water, he concluded that it might have come from the plastic sheeting used in the surrounding vineyards.

As an ideas man, passionate about finding biodegradable and home compostable packaging, he decided to do something about it.

His search led him to Italy where he sourced one kilometre of Mater-Bi, a bioplastic made from starches, cellulose and vegetable oils of non-human food sources, that is largely waste matter.

Last week, at the crack of dawn, viticulturist Etienne Southey and his team unrolled the bioplastic sheeting onto a block of new vineyards.

Mr Southey said they do not water the vineyards. This is a big challenge as the young vines struggle to settle during the first season. In the second season they need to grow enough to reach the wire strung from post to post.

Mr Southey said many wine farms are moving away from using wood chips and straw with plastic being the cheaper and tested method for mulch.

Black plastic creates a microclimate by keeping heat and moisture in while keeping weeds out because the sun cannot get through.

On the upper slope of a new vineyard near to the cellar they are trying three methods. One section has a dense mat of straw beneath new vines. Mr Southey said they tried straw last year but it is more expensive than plastic because it is labour intensive and must be removed at the end of the season.

The second trial is conventional plastic sheeting, which has to be removed at the end of the season and often not completely.

The third trial is the bioplastic sheeting. Mr Southey said the bioplastic was better to work with than regular plastic as it is more elastic and did not tear as easily. The bioplastic will be cheaper as it is a once-off job and biodegradable so does not have to be removed. His only concern is that plastic looks ugly and when it disintegrates it blows everywhere.

Mr Pollock said he will keep an eye on the trial. He said the other half kilometre of sheeting will be used at the Jordan Wine Estate in Stellenbosch next year.

Constantia Glen CEO, Dr Horst Prader, said the problem with plastic is that it can never be removed from the soil and it looks bad.

He said Constantia Glen is not organic but uses integrated pest management including wasps and ladybirds to control mealybugs, as do the other eight wine farms in the Constantia valley.

Mr Pollock said the bioplastic sheeting has other uses such as lining boots of
cars when people buy plants at nurser-

Paul Gordon, co-owner of Ferndale Nurseries, said he shares a common interest with Mr Pollock in riddling the environment of single use plastic.

“We’re currently negotiating with suppliers of biodegradable shopping bags to find the best quality product at a manageable cost. Already we try to minimise our plastic use by offering customers reused cardboard boxes as an alternative to bags which we collect from the recycling depos of the surrounding supermarkets,” said Mr Gordon.

He said the new agri-mulch sheeting would be the answer to their remaining plastic usage, that of car boot liners.

“Constantia is a green valley and so should be its vineyards,” said Mr Pollock.