Back in July 2013, we published a post discussing the delicate and controversial subject of whether or not only peat-free composts should be used by growers and gardeners. Our view was – and currently still is – that peat remains unsurpassed as a growing medium for plants in their first stages of growth. However, we ended the post with the following statement: “Does this mean that our plants will one day be sold with that ‘peat-free’ sticker? I think it is inevitable – when that sticker also means that the plant in the pot is still the best possible plant.”
Since then, we have continued to monitor available peat-free growing media and recently found one – it’s coir based – that looked promising. Further investigation including anecdotal evidence from reputable sources suggested that it really could be a viable alternative. We have therefore instigated a full-scale and properly monitored planting trial.
To avoid the results being skewed by possible leeching from the soil, all the plants in the trial are being grown in isolated special pots and troughs.
We have selected a wide and representative range of plants for the trial. Coir must demonstrate its ability to meet their varying requirements as successfully as peat:
- Common Beech (Fagus sylvatica)
- Common Box (Buxus Sempervirens)
- Hornbeam (Carpinus betulus)
- Photinia ‘Red Robin’ (Photinia x fraseri ‘Red Robin’)
- Yew (Taxus baccata)
The test planting also includes three Lavender varieties that will be grown in 2 litre containers:
- Lavender Grosso (Lavandula x intermedia ‘Grosso’)
- Lavender Richard Gray (Lavandula x chaytoriae Richard Gray)
- Lavender Stoechas Papillon
Coir is the fibrous, ‘hairy’ outer layer of the coconut. Until recently, it has generally been discarded by coconut processors. Its main benefit as a growing medium is its inherent ability to hold both water and air along with heating up rapidly, leading to early growth. Nutrients, however, leech easily and rapidly and at least a mix of NPK fertilisers must be added to coir compost. Given this, you may ask ‘why choose coir?’ The answer is that both wood and green waste composts, realistically the only two potential alternatives for large-scale growers, aren’t really that viable. At least, not yet. Once the volume of compost produced from green waste by local authorities and from recycled wood and other materials (including, for example, carpets) has reached a critical mass and products formulated, we’ll no doubt see new options. But until then, coir remains the only practical peat alternative for nurseries.
We will publish regular updates as the trial progresses.
These two factors are non-negotiable. If the plants grown in coir are not of the same quality as those grown in peat, this medium will be rejected and the search will continue. Similarly, the plants must demonstrate a comparable success rate. We will also establish if and how different species react to coir.
If the plant quality is achieved, we can then consider other factors…
The coir in our trial compost comes, like the vast majority of coir used horticulturally in the UK, from Sri Lanka. So, on the one hand it must be transported some 5,500 miles – hardly a hop, skip and jump away, even if it makes the journey as ballast in a container ship. But on the other, it is a genuine waste product and its sale and use has none of the environmental and social consequences associated with, say, the farming of certain bio-fuels. Then there’s water – we know that coir-based compost requires less water over time but more regular watering. This could have both environmental and cost implications and we need the trial to establish what they are. These are just two of the environmental considerations that need to inform our decision.
For many years we have only used pesticides as an absolute last resort, preferring to control whitefly, aphids, red spider mites etc. through close monitoring, natural predators and other non-chemical intervention. Would switching to coir require us to move away from this successful, environmentally beneficial and close-to-our-heart regime? We’ll see,
I’m not going to either justify or apologise for our need to make a fair and honest profit. Our staff would like to be paid and, frankly, so would my family and I. We are not looking to make more money, simply to sustain the commercial viability of our business. Of course, the coir alternative may be both successful and cost-neutral but we do have to ask this hypothetical question: if the trial is successful but require a price increase to our customers just to maintain our gross margin, how much of a premium will our customers be prepared to pay for hedging and edging plants grown in peat-free compost? Not everyone in business is greedy, but the first duty of anyone in business has to be to stay in business!