If you’re looking for a plant that thrives in the conditions inside most homes, try the crown of thorns plant (Euphorbia milii). Growing the plant is easy because it adapts well to normal room temperatures and in dry indoor environments. It also forgives occasional missed waterings and feedings without complaint. Crown of thorns houseplant care begins with placing the plant in the best possible location. Place the plant in a very sunny window where it will receive three to four hours of direct sunlight each day
From spring through late fall, water the crown of thorns plant when the soil is dry at a depth of about an inch, which is about the length of your finger to the first knuckle. Water the plant by flooding the pot with water. After all of the excess water has drained through, empty the saucer under the pot so that the roots aren’t left sitting in water. In winter, allow the soil to dry to a depth of 2 or 3 inches before watering. Feed the plant with a liquid houseplant fertilizer. Water the plant with the fertilizer every two weeks in spring, summer and fall. In winter, dilute the fertilizer to half strength and use it monthly.