Succulents work well in containers, and many of them thrive indoors. The group of plants known as succulents includes cactuses and many other plants with fleshy leaves and stems designed for storing water. Succulents grown as houseplants have a few special care requirements, and some species are better suited to indoor growing than others.
Choosing Indoor Succulents
Succulents vary in form and size. Some are suited to hanging baskets, while others have upright growth. Small succulents work well for cramped spaces or mixed planters, while others are large enough to grow as a statement plant. Not all have the same growing requirements, so choose carefully.
- Aloe (Aloe vera) doesn't need much care and will grow in low light or bright light. It can grow for years with no other care than watering every time the top 1 inch of soil dries out. Outdoors, aloe grows in U.S. Department of Agriculture plant hardiness zones 8 through 11.
- Jade plant (Crassula ovata, USDA zones 10 through 11) is a slow-growing succulent that prefers partial shade and can eventually reach 2 to 4 feet tall. The leaves are typically dark green, though some cultivars have leaves with red margins or white variegation.
- Paddle plant (Kalanchoe thyrsiflora, USDA zones 10 through 11) has flat, layered leaves on stems that can reach about 12 inches long. This succulent becomes gangling after blooming, and should be pruned once the flowers wilt. It will produce tiny plantlets you can repot to get new plants. It prefers bright, indirect light.
- Pencil cactus (Euphorbia tirucalli, USDA zones 9 through 11) is a branching plant that can reach 2 to 3 feet tall. The stems contain a white sap that may cause skin and eye irritation, so wear gloves when working with this plant and avoid touching your eyes until after you wash your hands. It grows best in bright light.
- Pincushion cactus (Mammillaria grahamii, USDA zones 8 through 11) is one of the easiest cactuses to get to flower indoors. It grows about 8 inches tall and thrives in bright light or partial shade. To make this plant flower, water a little more in spring and summer than usual.
- String of pearls (Senecio rowleyanus, USDA zones 9 through 12) works well in hanging baskets because of its trailing stems. The leaves of this plant are spherical like beads or green peas. It prefers bright light.
- Zebra plant (Haworthia fasciata, USDA zones 9 through 11) is a small, upright rosette plant that prefers lower light and has dark green leaves banded in white stripes. It grows best in shallow pots.
Pots and Soil
Both plastic and clay pots work for succulents. Clay pots dry out faster, so they are a good choice if you tend to overwater. They are also heavier, which helps keep large succulents, like jade plants, from falling over. Clay is more likely to break than plastic. Plastic pots are lighter in weight, unlikely to break and need less frequent watering. Standard pots that are taller than they are wide work well, but shallow pot are also good for succulents, especially shallow-rooted varieties like zebra plant. Make sure any pot you choose has drainage holes.
Succulents need potting soil that drains freely. Commercially available cactus mixes work well, or you can make your own. Mix 3 parts sterile soil-based potting mix, 1 part peat moss and 1 part 1/4-inch gravel. Do not use regular potting soil or garden soil, because it compacts too easily and will not drain well enough for succulents.
By itself, gravel is not a good planting medium because it does not hold nutrients or moisture. Small gravel can be used as a top-dressing to cover the soil's surface after planting. Top-dressings are a thin layer of inorganic material used like a mulch to reduce soil movement when watering and conserve moisture.
The biggest challenge when growing succulents indoors is providing enough light. If you have access to a bright, sunny window facing south or west with few trees outside to block light, you can grow most succulents. For parts of the home with less light, choose succulents that have a higher tolerance for shade.
For indoor areas without enough natural light, you can use artificial light. Fluorescent lights work well, but they must be close to the plants. An office lit with fluorescent bulbs in the ceiling won't be bright enough for succulents unless supplemented with natural light from a window or by placing grow lights above the plants.
A lighting fixture with one cool white and one warm white bulb placed 6 to 12 inches above the plants and lit for 12 to 16 hours daily provides enough light for succulents. If you want to grow succulents in a lower-light area, rotate them once a month to a spot with brighter natural light or closer to a fluorescent light.
Do not place succulents in drafty areas or where the temperature fluctuates. The tops of computers and areas near heating ducts can get too warm, while the temperatures near doors, air-conditioning units and on windowsills can get too cold.
Some succulents need more water than others, but as a general rule you should water after the soil completely dries out. During the growing season, this could mean only watering about once a month. If you overwater, the succulent's leaves will start to fall off or the plant will get mushy and rotten. If you underwater, the leaves and stems will start to shrivel.
Every time you water, give enough water that it drains freely out the holes in the bottom of the pot. After a few minutes, throw out the excess water that collects in the saucer under the pot. Succulents should never be left in standing water, which can lead to root rot.
Succulents need little fertilizer. Use a houseplant fertilizer once or twice a year for cactuses and three to four times a year for other succulents. Choose a fertilizer that contains more phosphorous than nitrogen, which means the second number on the N-P-K number on the label should be larger than the first number -- a 15-30-15 fertilizer.
Mix the plant food at half strength, and apply to the soil in place of a regular watering during the spring and summer when plants are actively growing. For a plant food with an N-P-K ratio of 15-30-15 that is normally applied at a rate of 1/2 teaspoon in 1 gallon of water, mix 1/4 teaspoon in 1 gallon of water for succulents.