The familiar Jade plant, Crassula argentea, has long been a popular houseplant. How it came into cultivation is clouded in history. Dutch explores and developers of shipping routes around the Cape of Good Hope in the 17th century sent back to Holland collections of living plants and seeds. This succulent plant, which grows naturally in broad areas from east to west in South Africa, was undoubtedly among those collected. A French naturalist reported in 1786 that the plant had been "growing for a long time" in the Jardin du Roi in Paris and he believed it came from Africa.
The popularity of the Jade plant as a houseplant is understandable because it will survive and even thrive under a wide range of conditions. It tolerates low levels of illumination and survives repeated dessication. Naturally, much healtier plant is produced in a sunny window with an adequate water supply.
The following cultural information is based on recommendations of horticulturists at Longwood Gardens as reported by the American Horticultural Society.
For optimum growth your Jade plant requires quite a bit of sunlight. Give it four hours of direct sunlight daily indoors, for instance in a west or south window.
The plant should be grown in a potting mix that drains well, such as one part shredded peat moss, one part soil, and one part sand. When the plant is root bound, transplant it to the next larger size pot or give it a top dressing of fresh soil.
From May through August water your plant sparingly. In winter months, soak the plant once a week. Let the soil dry out completely between waterings. Gradually increase the frequency of watering from September through February; gradually decrease, starting in March; this applies to young as well as old Jade plants. Too much water will cause leaves to split. Too much or too little water will cause leaves and whole stems to drop.
The Jade plants doesn't grow very much during the summer, yet it needs lots of fresh air; it can be moved to a sunny porch or patio during summer months. It enjoys warm temperatures in summer; in the fall and winter, keep it at 70 degrees in the daytime and 55 at night. Cool nights are a must for flower bud formation; rudiments of buds are formed in October; blooms come during December and January - on mature plants.
Fertilize only when the plant receives large amounts of water. Use an evenly balanced houseplant food (such as 20-20-20) once a month from October until it flowers; dilute the fertilizer to half strength, that is, use twice as much water as directions specify.
Red edges on the leaves of an older plant are a healthy sign. This means that the plant is getting enough sun. Old leaves are slightly spongy and full off the plant naturally, starting at the bottom and working up.
Avoid spraying pesticides, particularly malathion and meta-systox-R, in the area of a Jade plant. When the spray touches the leaves the leaves fall. The preferred means of getting rid of insect pests is to provide a brisk shower at the kitchen sink or spray the plant with mild soapy water and then rinse.
Jade plant leaves can be sponged occasionally with room temperature water to remove dust and restore their gloss. Never use a leaf-shine preparation; such products clog the leaf pores and inhibit the plant's growth processes.
The Jade plant has a distinctive character which accents modern decor, and because of its long history as a favorite houseplant it fits in traditional settings, too.
It is possible for the indoor gardener to bring a Jade plant into bloom although this seldom occurs except when the plant is mature and has been grown under high light intensity. However, the flowers are insignificant and should not be considered a measure of the worth of this plant or your success in growing it.