In my greenhouse

Contents of the Winter 2015 Northants News

All about my Grenhouse Trevor Wray

When I read Roland’s article on his greenhouse conditions to my cacti and succulents they announced they were leaving for Towcester straight away. Heated to plus 8ºC. Hot boxes. What luxury!

I am afraid there is a different regime here. I have three greenhouses here (well technically there is a fourth but that is the FL’s and it is a no-no for my plants). They are 12’x10’, 12’x8’ and 10’x8’, (sorry I don’t do metres). There are also about 14 square yards of cold frames which are covered by glass, (Dutch lights), in winter.

The coldframes are used to grow alpines, and many of these are succulents, (Sedum, Sempervivum and the odd cactus), and hardy bulbs and orchids that require winter dryness. There are also lilies and herbaceous plants in pots which are used around the garden in summer.

The smallest greenhouse and frames are not heated. The max/min thermometer in this greenhouse still reads -10ºC from the winter before last. It was even colder the previous winter. Here I propagate and grow sales plants. Most cacti and succulents from the Crassula and Mesemb family are hardy and remain there all winter, Aloes, especially the dwarf hybrids, and many Haworthias and Gasterias are risky and are moved to what I optimistically called my heated greenhouses when very frosty conditions are forecast. I didn’t need to do that last winter.

Right by the un-insulated glass; Mesembs on an aluminium shelf attached to an aluminium greenhouse. Keeps the roots nice and cool. Minus 2ºC generally in most winters. No problem.


A general view showing Lithops frozen on and off for 40 years.	Mostly Adromischus. These will survive freezing, just, but they don’t like it.	A selection of sales plants outside for the summer. Saves watering them.

The other two greenhouses are heated with 3kW electric heaters set at the frost-stat setting. Since they hang in the centre of the greenhouses the plants round the edge freeze and generally the max-min thermometer there records -2 ºC in a normal winter. You can guess that I do not grow any Brazilian or tropical plants.

There is little rhyme or reason to what goes into each greenhouse. Greenhouse 1, (they are numbered according to the order of acquiring them), has the Lithops, dwarf Crassulaceae and many of the smaller cacti. Greenhouse 2 is unheated. Greenhouse 3, (the largest), has most of the Rebutia group and the larger cacti and succulents, but it is not fixed. Probably the only system I use is that plants of similar size are close. This is because small pots need more frequent watering and in those (infrequent) heatwaves they may be watered every few days. Only the Lithops are kept in one area to facilitate water management and they are mostly kept dry from October to May.

I am generally successful with Lithops and other Mesembs and these are the plants I am most likely to win prizes with at shows. I wish I could grow Haworthias but struggle with them; when they lose their roots they often seem to just fade away. I do better now I grow them under the staging but I know better than to spend big money on these plants. I have a fair number of the genera of the Crassula family which I like for their colour and form and some have pretty flowers, though I would not say that was generally the strong point of the family. Of course most are easy to grow but so what? Why should I be influenced by the fashion police? Of cacti I grow at least a few of most kinds that are not tropical but like many growers I especially like those with strong spines and bright flowers. You have to go some way to beat Rebutias, Echinocereus and some Mammillarias.

Many plants I grow are re-propagated frequently. I do not see much point in growing large pans of clustering plants and when Rebutias, Crassulas, Adromischus and the like reach about five or six inches, I break them up. Vigorous young plants look and flower much better. The only exception to this is Lithops but these are hardly likely to outgrow their stay and I have 40 year old plants here.

So, have a reread of Roland’s article and his pampered plants. Then realise that for a great many of our treasures they do not need big heating bills.

Oh, did I mention that some succulents can be frozen even when wet? Why pay to heat Conophytum (and some other winter growing mesembs), Dudleya and Echeveria. Perhaps if the heating in our greenhouses is turned down the country will not need so many wind farms.

Trev

Left: One of those fancy Agaves, Most of them are OK in a cold greenhouse but I hesitate with this one. However –2°C seems tolerated.