Greenhouse Calendar

October

Now we have got the preparations for the Autumn show out of the way it is time to start thinking about settling things down for the winter. Sadly the growing season for cacti has come to an end for another season but, if you are lucky you may still have the odd Ariocarpus in flower and a few Mammillarias might be flowering for the second or third time. However, most cacti should be kept dry from about the end of the month until conditions start to improve next March. There are exceptions of course. Many epiphytic cacti flower during the winter including the many hybrids known as "Christmas Cacti" and these will need watering until after they have flowered. Remember that they do not like being moved once their buds have formed. Some South American cacti such as Notocacti can also be watered sparingly on bright days during the winter months.

Many genera from the large Mesembryanthemum family are actively growing at this time of the year. Lithops and Conophytum are giving an impressive display of flowers this month. Watering of Lithops can be discontinued as soon as they have finished flowering but Conophytums are usually treated a little differently with watering continuing at least until Christmas to help the new leaves to develop. Haworthias are also growing strongly at this time of year and should be watered accordingly but they do need to rest for a couple of months in mid winter.

Because there are so many Mesemb flowers at this time of the year, flower thrips may be particularly active in your greenhouse. They love lithops and conophytum pollen and they are not averse to taking the odd bite out of the epidermis of the plant in passing. Once the flowers have died they hide in the nooks and crannies between plant bodies and in the soil. They are partciularly difficult to get rid of and a combination of methods may be needed to control them. It is said that biological control (predators) is the only way to control them and that may not be 100% successful. The Pravado bug aerosol is useful and a powdered insecticide in the soil during the winter months could help. Also watch out for mealy bug on succulents at this time of year - they love to get down between the leaves where you cannot see them until it is too late.

Greenhouse Calendar

November

With luck some Lithops and Conophytums and perhaps some of the other mesembs will still be in flower at the beginning of the month but they will not be flowering for much longer. It is best to stop watering Lithops as soon as they finish flowering because there is enough moisture in the old leaves to give the new leaves a good start for next year. On the other hand Conophytums, with their small, sometimes tiny bodies, need to be watered a bit longer to give next year's leaves a chance to develop. Haworthias also can be watered until the end of the month when they will be ready to start their winter rest. Any other succulents that are in active growth (some Othonnas, Tylecodons, Dioscorea elephantipes and some mesembs) should also be watered carefully when conditions are suitable.

If you keep a database of your plants either on a computer or using an index card system this month is probably the best time to bring it up to date. This will include adding acquisitions that you have made during the year that have gone unrecorded. Also you will have the task of recording the year's losses which, hopefully, will be few. You can make new or replacement labels where necessary.

Greenhouse Calendar

December

Before talking about December an event in my greenhouse during November has shown me that I was not watering some of my mesembs enough for this time of year. A piece of moss had grown under the glass from the outside of the greenhouse. During the heavy rain earlier in November it acted as a wick from the outside of the greenhouse to one of the trays on the top shelf depositing water to a depth of about 10mm. This shelf had such choice specimens as Conophytums burgeri, hammeri and maughanii as well as number of Gibbaeums, Trichodiademas and Argyrodermas. I don’t know for how long they were standing in water ­ perhaps for a day or two and I was afraid that I would lose some, if not all of the plants. However, now, nearly a month later all the plants are looking better than they have ever looked and some have even flowered. My Argyroderma delaetii has two flowers and the Trichodiademas especially have flowered better than they ever have before. So it just goes to show that there are times that even the most succulent mesembs will take a fair amount of water, the trick is in knowing exactly when that is. I am sure if this had happened at another time many of these plants would have split with this sort of treatment.

December is the quietest month in the greenhouse year, the days are short and, with the exception of a range of South African succulents, almost everything is dormant. There are those growers who do not water anything during December and January but Conophytums can take a little water at this time but only on brighter, sunnier days. Any plants that are kept in centrally heated areas indoors or in special areas of the greenhouse where the temperature is higher should be watered lightly once every two weeks ­ more often if they are actively growing.

If you feel that you should be doing something in the greenhouse this is a good time to start repotting. Because the dormant plants will not notice that they have been moved and when they wake up they will have new compost to give them a good start to the new growing season. I like to incorporate an insecticidal powder in the fresh soil to discourage over-wintering soil pests.

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