Dial-a-Tree Virtual Tree Nursery
Tree Stuff Blog
Which is greener - plastic or peat?


The Old Ways

Organic for thirty years, most of our trees are containerised in the familiar black plastic planter bags or root trainers. I am occasionally asked by friends and customers - how can plastic be organic? I would give the flippant answer, that petrochemicals are made from organic molecules. The fact is plastic containers are a recent development in the nursery industry and they have always been consumer driven. Not long before my time and even now in many places, Italy and Oregon amongst them, trees are dispatched in winter with bare roots wrapped in a wet jute sack for immediate planting. Even within my limited lifespan, seasonal strawberry plants and onions were always sold in country stores and post office shops in wet newspaper twists sitting in a saucer. We planted 6000 pines for the plywood factory which arrived bare rooted in bags of 300 trees in cardboard boxes. So it is possible to trade plants without plastic pots. And people do. It's cheaper, but it needs planning and care.

Trees in boxes ready for planting

Too Damn Handy

But most buyers are spontaneous, inflexible, busy, even disorganised. People want to buy trees on a whim one afternoon; sit them behind the garage for a month; remember them and plant half now, half later. The trees need to be easily transported and individually potted so they survive total abandonment until the planter feels like digging. To meet these requirements plastic pots are stronger and more permanent than anything short of a terracotta pot, and they are lighter than clay to carry. So a huge modern industry has built up around plastic plant containerisation. But now, with plastic pollution becoming more of a problem we are forced to look at the alternatives. In the eighties we would save all our recycling, tubs, pots and milk cartons, and turn them into colourful plant containers. These looked garish (and dare I say fun) but buyers didn't like it and saw only rubbish - and therefore probably thought the plants were rubbish. Also people used to return rootrainers and used pots to the nursery back in the day. Now they don't. I wish they would. Even only re-using each pot one more time, would halve the world's production of plastic pots! Or to put it another way, one single re-use of a container means halving the cost of that container. So in fact re-using pots is the greenest possible thing to do, because it slows the pressure to produce new ones.

Re-used juice cartons: the eighties look

Peat Pots and the Like

Anyway nowadays they have to look tidy AND hopefully be biodegradable. In the commercial industry there are a few products which stand out. One is paper, ingeniously stuck together so it folds out into a hundred hexagonal planting cells which stay open when filled and are great for a hundred plants at once say, for bulk herb plants or small trees. The downside is you cannot divide the hundred and they need a container to support themselves (made of what?). Also they will begin to biodegrade after a season. They may collapse or dissolve leaving the plants needing to be repotted. However paper can be a fully sustainable product. Unbleached paper from pine forests could be organic too.

Other products are based on moulded fibres. Peat pots, known often as jiffy pots, have been around for years and are making a big comeback. The pots are made of - hopefully - sustainably harvested peat from Estonia or Canada. Young plants grow their roots right into the pot walls. They naturally air prune as well as feeding from the pot itself (some pots are impregnated with extra nutrients). You transplant the whole thing, pot and all, into its new site, reducing planting shock. In fact most plants love them. So they are great for the plants themselves. Peat mining has its opponents and some might see this as mining a fossil fuel, even though on aggregate this peat is returned to the earth when you plant the seedling. Serious organic devotees (like me) question the wisdom of importing northern hemisphere peat into Aotearoa, which may be strip mined unsustainably or even contain unwanted pollutants such as Chernnobyl or Fukushima radiation. The new kid on the block is the wholly sustainable biodegradable "bio-pot" which is similar to the peat pots but moulded without the peat. These are made from paper mache or wood chip fibre, as well as corn stalks, hemp fibres or other agricultural fibrous byproducts like coir. These sound ideal although as with the peat pots, they dissolve in heavy rain and degrade (fall to bits) from the day they get wet, so they are also short lived, as well as costing three times the price of plastic pots.

Bio pots dissolving in the West Coast rain

Re-using Plastic

If you can't re-use the peat pots, and they only last one season, then why not re-use the plastic pots, year in year out? Rootrainers were originally made much thicker than they are now. And we re-use them at dialatree nursery, sometimes for four seasons or more. If we all re-used plastic containers multiple times it could reduce the world's plastic production by heaps every year. The plastic is durable which is an advantage. When re-used it means there is no need to make or buy another new product, and their cost is immediately halved. The ideal would be a starch based, strong, biodegradable plastic such as is used to make takeaway coffee cups. And cutoff juice bottles are awesome too. So the question of which is greener, plastic or peat, is a complex one, and for now, we will continue to use plastic, particularly for freighting plants on long, bumpy inter-island journeys. But we are beginning our own journey away from petrochemicals, toward a more natural style of plant containers.

Peat pots at 16 cents each; reused tubes on their second run at 6 cents each - 3 cents per use.

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