A curry leaf plant (Murraya koenigii) should grow well in a sunroom. These plants only grow well outdoors in the warm climates U.S. Department of Agriculture plant hardiness zones 10 through 12. Proper care, temperatures that never dip below 40 degrees Fahrenheit, and plenty of sunshine -- at least six or more hours -- encourage healthy growth. Use the leaves in cooking or to mix your own curry powder. If your sunroom is warm enough, you can also help prevent the curry leaf plant from going dormant in winter, but even if it does, it will return with full vigor in spring.
Fill a clay pot with well-draining potting soil. Slide the curry leaf plant out of its current container and place it on the soil. Fill the soil around the root ball so the plant is sitting at the same depth as it was in its previous container. A clay pot with drainage holes resists tipping and helps keep the soil at the right moisture level. water the plant well after repotting.
Water curry leaf when the soil feels dry to the touch about 2 or 3 inches deep. Pour enough water that you see some of it drain out of the bottom of the pot. If water collects in the drainage dish, dump it out. If the tree loses its leaves, despite the warm temperatures in the sunroom, and goes into winter dormancy, allow the soil to completely dry out between waterings.
Fertilize curry leaf once a week at watering time with a water-soluble houseplant fertilizer for leafy plants. These often contain a 20-20-20 nutrient analysis. Apply half the recommended dosage that is written on the label, often 1 tablespoon mixed with 1 gallon of water is enough. If the curry leaf plant stops growing and goes into winter dormancy, stop fertilizing until spring.
Prune damaged or dead curry leaf branches back to healthy growth at any time to keep the tree attractive. Also, cut off suckers -- which can be used for propagation --- that grow from the bottom of the tree. Use sterile pruning shears that have been disinfected with rubbing alcohol or a disinfectant spray.