When most people think of cacti, this type usually comes to mind. Adapted to living in desert conditions, these cacti are often heavily armed with spines. While many have beautiful and delicate flowers, they are mainly grown for their unusual shapes, colors and textures.
CULTURE OF ARID CLIMATE CACTI

Watering properly is the most important factor in growing cacti successfully. Their soil must be very well-drained. During the growing season from March to September, cacti will grow rapidly. Water them as any other houseplant that prefers to dry slightly between waterings. In winter, while the plants are dormant, they should be allowed to get very dry between waterings. Water them just enough to keep them from shriveling. Usually this will mean a light watering every few weeks.

The plant must never be permitted to stand in water. Waterlogged soil will quickly lead to rotting of the roots.

Arid climate cacti need bright sunlight. Windows facing south or west where they will receive direct sunlight for several hours each day are ideal. Artificial light may be necessary to supplement natural light.

Cactus plants actually prefer a rich soil if it is free-draining. Packaged, commercial cactus potting soils may be used or you can make your own by combining equal volumes of peat-based potting soil and very coarse sand or grit.

Cacti generally like to be slightly pot bound. They should be repotted only as needed. April is the best time to repot cacti, just as they begin summer growth. When repotting be sure to wear heavy leather gloves or wrap the cactus in several layers of newspaper for handling. Repot cacti into a container only slightly larger than the present one. If the container is too large, the soil may stay moist and lead to rot. After repotting, wait several days before watering.

Use a low nitrogen fertilizer such as 5-10-5 once a month from June through September. Time-released fertilizers can be used, applied once in the spring. Do not fertilize repotted plants or arid climate cacti during the winter.

Cacti prefer temperatures from 65 to 85 ° F during the growing season. Dormant cactus plants do best at temperatures from 45 to 55 °F in winter. An ideal placement for a cactus in winter would be a sunny cool room or near a window where it is cooler. Most will tolerate normal house temperatures, but they are more likely to flower and prosper if kept cool in winter.

Cacti can be moved outdoors during the summer, and will respond well to the change. Be sure to place them in partial shade for the first few weeks, allowing them to adjust to brighter light.

Cacti can be propagated from seeds, cuttings, grafting or offsets.
TYPES OF ARID CLIMATE CACTI

Star Cactus (Astrophytum species): These easy-to-grow, green spineless cacti have white flakes on the outside of the ribs.

Sea Urchin Cactus (Astrophytum asterias): This small spineless cactus has a gray-green to white-green body. Bright yellow flowers with red throats appear after about five years. In winter, when dormant, the saucerlike body shrinks to a flat disk.

Goat’s Horn Cacti (Astrophytum capricorne): Wiry, gray to brown spines twist around this small cacti. Flowers often have a wine-red throat.

Bishop’s Cap (Astrophytum myriostigma): Spherical, covered with tiny white-wooly scales along ridges of brown, spineless ribs. Flowers are yellow.

Star Cactus (Astrophytum ornatum): Spherical when young to columnar when mature, ribs with cross bands of wooly scales between brown or yellow spines. The flowers are yellow.

Golden Barrel cactus (Echinocactus grusonii): Upright barrel-shaped green body is covered with heavy gold-yellow spines. The flowers are gold. This cactus is good for beginners.

Giant Saguaro (Carnegeia gigantea): This is the familiar cactus shown in western films. It has a solitary trunk and outstretched limbs that resembles arms. White flowers appear in spring. It makes a nice container plant when young.

Barrel Cacti (Ferocactus): Ferocactus have extremely fierce-looking, long and ornamental spines. These cylindrical cacti are usually around 5 to 6 inches in diameter, but can grow up to a foot or more. Large flowers appear in summer on older specimens.

Compass Barrel Cactus (Ferocactus cylindraceus): The long, hooked flame-red spines of this barrel cacti become very dense with age. Bell-like flowers are orange and yellow.

Crow’s Claw Cacti (Ferocactus latispinus): With age, the red spines become broad and hooked and lay flat against the ball-shaped barrel. A mature plant reaches about 10 inches tall by 15 inches wide. Cream to purple flowers appear in spring.

Candy Barrel Cactus (Ferocactus wislizeni): Distinctively patterned red and white spines and yellow, orange or red flowers. It tolerates abuse and neglect well.

Prickly Pear Cacti (Opuntia species): Low mat-forming prickly pears are very easy to grow. Always wear heavy gloves when handling prickly pears. They have tiny barbed bristles on their stems that can cause more pain than larger spines and are difficult to see. Most have large, flat, oval pads and showy flowers. They produce colorful, edible pear-shaped fruits. Many types are also hardy outside.

Bunny Ears Cactus (Opuntia microdasys): Grows up to 2 feet tall and wide. The round stems are velvety green. The flowers are bright yellow.

Grizzly Bear Cactus (Optunia polyacantha v. trichaphora): This species has a unique form when mature. It is a large padded variety with white spines.

Hedgehog Cacti (Echinocereus species): Small globular cacti covered with short spines; flowers profusely. They are easy-to-grow plants and good for beginners.

Claret Cup Hedgehog Cacti (Echinocereus triglochidiatus): They have prominent ribs and brilliant scarlet flowers in summer. When mature they may spread to form a 2-feet-wide clump.

Rainbow Cacti (Echinocereus rigidissimus v. rubrispinus): The short spines of this small clumping cacti occur in red and white bands. A ring of pink to magenta flowers appears on the crown of each stem. Flowers when relatively young.

Chin Cacti (Gymnocalycium species): These small compact cacti are perfect for windowsills and limited spaces. They will flower at an early age and flower often. Flowers are white and pink, sometimes red.

Pincushion Cacti (Mammillaria species): This is a large group of small, free-flowering cacti that are easy to care for. Most are densely spined, and in many types the spines are so elongated and soft that the plant appears hairy.

Giant Snake or Crawling Log Cacti (Mammillaria matudae): Mature specimens develop into a low mound of long, snaking stems.

Snowball Pincushion Cacti (Mammillaria candida): The body of this small clumping cactus is cloaked in dense white spines, which are often pink-tipped. It produces rings of flowers in spring, that begin cream colored, then turn pink.

Powder Puff Cactus (Mammillaria bocasana): It grows as clumps of spherical blue-green stems covered with short, dense, wooly spines. The flowers are small and white or yellow.

Snowball Cushion Cactus (Mammillaria candida): Spherical cactus is greenish white, with felted pink spines.

Old Lady Cactus (Mammillaria hahniana): This is a solitary cactus that is spherical, with short, dense, white hair and purplish red flowers.

Rose Pincushion Cactus (Mammillaria zeilmanniana): This cactus grows in hairy white clusters with red-violet flowers.

Golden Ball Cacti (Notocactus species): This is a globular, clustering cactus with harmless yellow spines and beautiful yellow flowers.

Golden Powder Puff (Parodia chrysacanthion): Mature plants are covered with golden spines and dense white wool on new growth. Small, yellow flowers appear in spring and summer.

Column Cactus (Cereus uruguayanus): These upright cacti grow up to 3 to 6 feet indoors. They are a smooth blue-green with brown spines. The flowers are white with outer petals tipped various colors and open at night.