As with all cacti the plant should be kept completely dry for the winter months and with in minimum temperature of 8degC.
Notes on Cultivation
Cacti originate from the desert regions of South America. Therefore, soil, lighting, temperature, and watering are all very important factors in the care and cultivation of cacti.
Containers
Clay and plastic containers are equally suitable for cacti, although clay pots dry out more quickly, which is sometimes helpful when dealing with the more delicate species. The containers should be large enough to accommodate the roots but not too large for the plant. Generally it is better to use half pots as must cacti tend to be shallow rooted. Although as with most things there are always exceptions as some plants will produce a 'tap' root which will require additional depth.
Compost
There are two schools of thought when it comes to the choice of compost. Some growers prefer to use a soil based compost, others choose a soil less or Peat based compost. Whichever soil type is important that the medium is kept well drained by adding gritty sand to the compost at the ratio of one part grit to two parts compost. Crocks must always be added to the bottom of the pot to ensure good drainage. I have used Arthur Bowers potting compost for many years now with great success.
Shade loving species Zygocactus truncatus
Watering and Feeding
Success of growing Cacti depends largely on the correct watering. Over-watering can lead to Black Rot and must be avoided at all costs. As a general rule for myself (living in the South of England) I water throughout the Spring and Summer from early March to Early September. The frequency however will depend upon the weather. It is important to only water when the compost is nearly dry. For the Winter months the plants are kept completely dry. They require this period of rest to encourage flowering. Feeding although important must not be overdone and only given when the plants are growing. There are a number of proprietary Cactus fertilisers available from Garden Centres I have used 'Chempak Formula 8' for many years with good results.
Light
Different species of cacti require different amounts of light depending on their original habitat. Desert Cacti require the brightest and sunniest possible. Jungle and rainforest Cacti however dislike direct sunlight and benefit by being in the shade of larger plants.
Another very desirable species Turbinicarpus schwarzii
Temperature
In the Summer months the temperature in the greenhouse can quite easily reach the dizzy heights of 30deg C. With these high temperatures it is important to maintain good ventilation. It is also wise not to water or spray in direct sunshine as this can cause scorching.
In the winter the temperature can be allowed to fall to 8-10deg C throughout the dormant period for the plants. It is best to heat the greenhouse using an electric greenhouse fan heater that can be set to switch on at the required temperature. A min-max thermometer is essential to keep track on the temperature changes. I would not recommend the use of Paraffin heaters as they are difficult to control produce water as a by-product of the combustion. Cacti need a dry atmosphere during there dormant period
The colourful flower of Pelecyphora aselliformis
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Cristates
A crest or 'cristate' shape emerges when the vegetative point grows very evenly but repeatedly divides into two. The crest curls while already growing in all sorts of curved shapes. Monster shapes almost always have to be grafted to stay alive. There are some specialists that only collect cristate cacti.
Typical example of a cristate,
Mammillaria scheidweileriana cristata
There are many variations of cristate that occur in all shapes sizes and colour. As a general rule very few produce flowers, but are still attractive because of their unusual appearance.
A freak form of the species Gymnocalycium mihanovichii is 'Gymnocalycium mihanovichii cv hibotan'. The unusual colouring is due to a lack of chlorophyll when the seed was germinated. Its survival depends upon its being grafted onto a robust stock such as 'Hylocereus'. Regardless of its peculiar existence, it nevertheless is able to produce attractive pink flowers.
