With its fleshy, succulent leaves, sweetheart hoya is relatively drought-tolerant and can get by with as little as one or two waterings per month. Water deeply when the soil is slightly dry to the touch, then let the pot drain thoroughly.
Any food with a 2:1:2 or 3:1:2 is sufficient to keep the plant in good health. For wax plants that are flowering, however, switch to a 5:10:3 with a high phosphorus number to encourage blooming. Use a high phosphate fertilizer for 2 months prior to the plant's normal blooming time
This Valentine hoya tolerates relatively low light, but not full shade. However, the plant performs best and is more likely to bloom in bright or indirect sunlight. Room temperatures should be maintained between 60 and 80 F. or 15 and 26 C.
The optimum temperature for Hoya sweetheart is 65°F – 80°F, which is the range for average room temperature. People living in temperate regions can grow the plant in pots outdoors during summer and take them indoors during colder seasons. Leaves turning yellow may be an indication of too much exposure to light.
All you need to do to repot a heart-leaf hoya is to remove it from its existing container. Half-fill a new, slightly larger pot, with appropriate potting mix. Put in the plant and fill the pot with soil. The best time to repot houseplants—including lucky-heart hoyas—is in the spring, when growth is vigorous.