Place the plant in the hottest location of your house, or set outdoors in full sun. If you live in a location where temperatures do not drop below 50 F, then you can plant it outdoors. Otherwise, grow it as a houseplant. Water heavily and deeply the first time you bring your henna plant home.
Provide occasional, deep watering. Henna likes it hot and is endemic to regions with monsoon weather, where there are alternating periods of drought and flooding. Rather than watering daily, allow the soil to dry out each time you water. Too much moisture can result in root rot, aphids or scale insects.
Prune branches back and repot if your plant begins to shed its leaves. This will encourage new growth and vigor. Shedding leaves may result from a cold chill or pests, and is a sign that the plant may benefit from fresh pruning.
Cut leaves from the plant when it is large enough to sustain the removal. Use for clothing or hair dye. The youngest leaves have the highest concentration of petiole, the substance used for dye.
Plant henna seeds in pots when soil temperature is 75 F. Cover with a light layer of compost. Henna seeds are small, brown and shaped like polygons. Their fruit ripens in late summer and contains 40 to 45 seeds each.
Place the pots in plastic bags and store in a warm location to speed up the germination process. Germination may otherwise take months to occur.
Place germinated seedlings in a warm, sunny location.
Transplant to a larger pots in spring.