Sunday, 8 March 2009

The first shoots of spring?

It may look inconsequential to most people, but the photo above shows the first Canna shoot of the year for us at Claines Canna. The plants are all in the soil inside poly tunnels, where they have been since the frosts cut down the summers top growth last October.

The weather has now turned and the first signs of spring can be seen; of course we still have a way to go before we can say that winter is truly over, but the winter blues have now left the writer and we can look forward to better things ahead.

One of the advantages in using a polytunnel is that the specially formulated plastic covering traps heat from the sun and the daytime temperatures in the tunnel will be at least double those shown on the graph above. This has the effect of heating the soil during the day and when the outside temperatures drop overnight that stored heat will double the tunnels' overnight temperatures, as shown above.

If a Canna enthusiast has just a few specimens then the time honoured advice to store in a greenhouse or garage is still the most appropriate, but for anyone with a large number of plants to over-winter I would suggest that they consider growing in the ground inside a poly tunnel as a serious, proven, and practical approach.


  1. I agree about the green house remark, Having used a Tunnel before and now a green house, I can truly say that green houses are not in the same league as Poly Tunnels.
    My seedlings got hit by frost! In the green house with one of those paraffin heaters (a parasene big red, avoid), I never had any trouble with a tunnel even when temps dropped blow -10...

  2. Blimey, this is early! I have a couple of Cannas I left outside although I guess it's a good bit colder out there but hopefully I'll see signs of life from them soon.

    I've also got several in a cold frame, so maybe they'll start growing a little sooner? Might move them into the greenhouse to get them going...