Potting Mix

Visitor's picture

Just finished checking 51 plants in pots which have travelled 900 kilometres and were effectively under cover for 4 days from Thursday 27th to Sunday 30th. They all appear ok and about a dozen had also endured being inside for two days at a local show the previous weekend. Last year I had similar good results after taking 60 plus pots north to the annual Nelson AGS show. That also involved a round trip of 900 kilometres. In previous years I had always suffered serious losses after taking plants on such long journeys and put the cause down mainly to the length of time the plants had been confined inside low light buildings.

Last weekends’ excursion was to support a three day show put on by the Otago Alpine Garden Group in conjunction with the Dunedin Horticultural Society and an International Daffodil Show. I put the vastly improved ability of my plants to endure such travel stress down to one change made after the Christchurch 2010 September earthquake. Below a picture of some of the damage.

At this time, a few days before the 2010 Otago show, I faced a major rethink on how to manage the collection. The simplest way to seemed to be to convert from recycling old potting mix to universally introducing a new mix. For some time I had been contemplating changing the “sharp gravel,” added some years before to the composted bark, for a “smooth river washed gravel”. It would not have been an easy task to make the change and had just carried on recycling the old mix, adding quantities of bark to replace the fine particles of decomposed bark removed during the recycling process. To clarify this I should add that no new potting mix had been bought during the previous eight years.

With a sand supplier a few hundred metres down the road the change was made to a rounded river gravel 2-4mm grade. The new potting mix using this gravel has since been used for all my larger and more mature plants which of course are the ones taken to various shows. After all the gravel seems to be only there for ballast, without it everything would soon be on its side with the very strong winds we experience here in North Canterbury.

Apart from me being told my hands are a lot smoother there has no noticeable change except for the improved condition of the plants after travelling.. The obvious conclusion is that with sharp gravel in the potting mix root damage was occurring on every trip, with the rounded gravel ----- problem solved.

It is not just earthquakes and high winds that make life interesting here, four months ago the plants above were under snow.