Let's get acquainted with Cacti. Just so you will know, Cacti is the plural form of Cactus. Cacti make good rock garden plants and they come in many varieties that you can pick from. I will be give you some general information and then discuss outdoor and indoor cultivation, and how to take cuttings of Cacti and starting seeds.
General Information on Cacti
Cacti is the collective name given to the describe various members of the family Cactaceae. They are originally from the Americas, particularly in Lower California, Texas and Mexico south to Chile, Peru, and Argentina.
The members of the Cactus family exhibit great diversity of form: some are small and resemble stones in shape and coloring; others form tall columns 20 ft. In height. The branches and stems of some kinds are flattened, whereas many develop into almost round masses of tissue. A few form true leaves, but in the majority the foliage is reduced to microscopic scales. Some are armed with sharp, pointed spines an d all have a very thick outer skin. The absence of leaves and the thick skin enable these plants to flourish in dry, barren climates where most other vegetation can not exist; this is because transpiration (giving off of water) in Cacti is reduced to a minimum.
During the rainy periods Cacti are capable of storing up large quantities of water which is utilized during periods of drought.
In addition to being curiously attractive in form, many Cacti also bear showy flowers of many beautiful shades, and some are night-flowering, as, for example, the large, fragrant, white Selenicereus (Cereus) grandiflorus.
The Cactus family includes more than 120 genera, which collectively contain over 2,000 species.
In warm, dry sections of North America a great variety of Cacti may be successfully cultivated in the open garden. In warm, moist climates fewer kinds succeed but still a selection may be grown, and even in the northern US a few succeed outdoors in sharply drained (very porous) soils. In such cold climates a location at the base of a south-facing wall is a good place to plant the hardier kinds, one of the easiest of which is the eastern North American native, Opuntia compressa.
Cacti require a minimum greenhouse temperature of 40 degrees and 10 or 15 degrees more is advantageous. With few exceptions they must be exposed to all available sunlight throughout the year. There are a few exceptions to this rule. The best potting compost consists of four parts sandy loam, and one part of equal quantities of sand and crushed brick.
Repotting is done in April, the plants should be moved into larger pots when their roots become cramped. As a general rule, Cacti should be repotted every second year, as after that the soil tends to become sour; but that does not mean they will have to have a larger pot.
Good drainage must be provided about one quarter of the pot space should be filled with crocks, covered with coarse leaves, and the soil must be made firm with a potting stick. After repotting, no water is given until the soil becomes almost dry.
When the plants are established, the compost is kept moist from April to October. From November until March less water is required, sufficient only to keep the stems from shriveling.
When Cacti are grown for window gardens, or window boxes, where winter temperatures are markedly higher than those recommended above for Cacti grown in greenhouses, more frequent watering is needed during the winter months.
How to Take Cuttings of Cacti
Parts taken from anywhere on the Cacti can be readily rooted. When cuttings are taken they should be laid in the sun for a day or two to allow a corky skin to form over the cuts, which prevents rotting, They are then inserted in pots of equal parts moist peat and sand or in sand alone. They should then be placed somewhere the greenhouse were it will get light. A propagating case is not necessary, although slight bottom heat will induce quicker root formation.
Cacti can also be raised from seeds.
They should germinate with temperatures of 60 to 70 degrees. Keep the seedling somewhat shaded from strong sunlight, and carefully watered until large enough to pinch off at an inch apart in pans of porous compost. Later, they are transferred singly to small, 1 inch wide pots.