Answer: Your Crown of Thorns (Euphorbia milii) should be an easy plant to care for indoors. It likes a south facing window with lots of light, and prefers temperatures about 70F degrees. If you feed your plant too much, it may become leggy, but you can give it diluted (half-strength) liquid fertilizer during the summer months if it doesn't seem to be thriving. Overwatering or lack of sufficient light can cause the leaves to turn yellow and fall off. I'd move it to a brighter location and see if that doesn't help perk it up. You'll probably need to water less during the winter months, so don't let the soil completely dry out, but wait until the top half-inch is dry before supplying water to your plant. Expect that the plant will rest a bit this winter, but should begin growing again in early spring when the days get longer.
Best wishes with your Crown of Thorns!
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