Today's Gardener (todaysgardener.com) is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. This site also participates in other affiliate programs and is compensated for referring traffic and business to them.
Keep the temperature between 10 and 21 degrees C during the warm summer months. These plants cannot tolerate frost and the minimum they can take is 5 degrees C. Keep away all Haworthia types from droughty windows and move them inside when everything becomes covered with a white winter blanket.
Regular household humidity will suffice.
Position and light:
It does not require continuous sun, but grows best in a spot that receives bright light for 3 hours and some full sun around 1 or 2 hours a day, ideally near a windowsill that’s not in direct sun or on a high shelf near the top of the greenhouse. Southern or western exposure is advisable. Shade greenhouses in the summer. Provide a slight breeze and fresh air.
Plant haworthias in humusy, sandy, or gritty loam-based potting soil with compost included or soilless potting mix with 30 percent sand for good drainage.
Since Haworthia types store water in their leaves, water them only when the soil is dry and never water during the resting period which is four to six weeks at the peak of summer. Water every two weeks in spring and summer, weekly in hottest months, but always allow the soil to dry out first. Keep dry in winter.
Apply high-potash fertilizer 3 times in the summer. It performs well with no fertilizing, though.
Repot every spring in a pot that’s one size larger than the previous one. Shallow-rooted plants perform better in half pots. Refrain from watering for 2 weeks.
Propagate by cutting offsets and potting up. You can also start a new plant from seeds. Remove whole shoots or individual leaves with a sharp knife. Apply rooting powder and tap. Dry for 3 days. Pot in fresh soil. Water after 3 weeks, when roots are formed.
Spider mites or mealybugs may appear on any Haworthia types. Remove them with a small paintbrush dipped in alcohol. Repeat the process in the growing season.
If ends shrivel, the air is too hot and dry. If the leaves are long and pale, it is too dark, hot, or wet. If plants grow slowly, you are likely overwatering or soil is too heavy and compact. So check the roots and repot in fresh soil after applying rooting hormone with 30 percent coarse sand.
If leaves blacken, it is too cold and wet and humid. Cut off the affected leaves and allow the soil to dry out.