Crossandra

bright indirect light (3-6 feet from a south or west window, or right next to an east window. Under a grow light, 6-10 inches away works well). Some morning direct sun (right in the window where sun actually hits the leaves. A strong grow light 4-6 inches away can substitute) is fine; avoid hot midday sun. Plants that fail to bloom are almost always not getting enough light. In low light (more than 8 feet from a window, or a north-facing room. A grow light 10-12 inches away works great if your windows are not cutting it), move closer to a window rather than reaching for fertilizer.

Moderate to high - aim for 50% relative humidity or above. Place on a pebble tray with water beneath the pot, or group with other tropical plants. Keep away from heating vents and radiators.

Loamy, well-draining mix rich in organic matter, slightly acidic (pH below 6.0). Standard peat-based potting mix works well. Roots like to be a little snug - avoid oversized pots.

Mealybugs, whitefly, aphids, and spider mites are occasional pests - spider mites are more common in dry conditions, so maintaining humidity is partly preventive. Root rot from overwatering is the most likely cause of sudden decline.