How to Grow Haworthia
Haworthia is not considered difficult houseplants to grow—if you can keep a pot of aloe alive on a windowsill, chances are you can do the same with a dish of Haworthia. As with all succulents, the most dangerous situation is too much water, since they should never be allowed to sit in water under any circumstances.
Haworthia species like bright light, but not direct sunlight. These grow in similar conditions to other succulents. In their native environment, they are often found in the shade of a rock or other object. They do best in a room with a window facing east or west to provide bright light for a few hours a day. White or yellow leaves usually signify too much sun. If the plant isn't getting enough light, its green color will fade. If you move your indoor Haworthia outdoors for the warmer months, ease the plant into more and more direct light per day or, like a human, it may get a sunburn.
Use a cactus mix or very fast-draining potting soil. Many growers warn that mixing potting soil with sand clogs up the pores so the soil doesn't drain as well, so sand should be avoided. Instead, mix with perlite, aquarium gravel, or pumice.
Water evenly and generously in the summer, letting the soil media dry out between waterings. In the winter, reduce watering to every other month. Never allow water to collect in the rosette.
Temperature and Humidity
Haworthia species like warmer temperatures in the summer but cool in the winter (down to 50 degrees Fahrenheit). They can get a freezing injury at 40 degrees Fahrenheit. This plant doesn't need any humidity. What it does require is good ventilation, especially at night when they take in carbon dioxide for photosynthesis. You might use a fan to keep air circulating so your Haworthia can breathe.
Fertilize during the summer growing season with a cactus fertilizer. Don't feed during the winter.
Potting and Repotting
Haworthia are small (usually remaining between 3 inches and 5 inches in height) and relatively slow-growing. They are often grown in small clusters in wide, shallow dishes. Over time, clusters will naturally enlarge as the mother plant sends off small plantlets.
When the cluster has outgrown its dish, repot in the spring or early summer into a new wide and shallow dish with fresh potting soil. This is also the time to take offsets for propagation.
Haworthia can be propagated at repotting time using offsets from the mother plant. When taking offsets, use a sharp knife or snippers and cut as close to the mother stem as possible to include as many roots as possible, then allow the offset to dry briefly before repotting it (similar to cuttings from other succulents). Pot the offsets in a small pot, using the same soil as the mother plant. Put it in a warm, bright spot, and make sure to adequately water.
Varieties of Haworthia
There are about 80 species of Haworthia, but their classification can be complex. The main difference between the common species is the size of the leaves and the orientation of the white markings on the leaves. In general, the best advice is to buy the most attractive variety based on leaf form and markings, as they all have similar cultural requirements. Look for these:
- H. margaritifera has warty white projections on the leaves.
- H. fasciata features horizontal white stripes and is sometimes called the zebra plant.
- H. bolusii have "tufted" edges to the leaves.
- H. attenuata features long, pointed green leaves.