How to Grow Euphorbia Plants

Provide the selected variety of Euphorbia full sun or at least six to eight hours of direct sunlight every day. Select a well-draining planting site if you're growing the Euphorbia outdoors. For indoor growing, use a pot slightly deeper than the root system of the Euphorbia, and fill it with equal amounts of sand, compost and potting soil. If required, drill evenly spaced drainage holes through the base of the pot to prevent root rot.

Provide a slow and steady stream of water to the Euphorbia plant once every week during the growing season. Let excess water drain out through the base of the pot, and reduce the frequency of irrigation to once every five to six months during the winter.

Spray the indoor Euphorbia during the summer to increase humidity. Alternatively, place a humidifier near the plant. However, skip this step if growing the Euphorbia outdoors.

Feed the Euphorbia a 5-10-10 or low-nitrogen fertilizer diluted to half its strength in late spring or summer. Water the plant lightly before fertilizing it.

Dislodge pests such as spider mites, aphids and mealybugs on the foliage or stems of the Euphorbia plant with a jet of water from a garden hose. Treat fungal diseases such as powdery mildew with a registered fungicide, and avoid overhead watering to reduce chances of this common disease on Euphorbia species.