How to Grow a Moonflower Indoors

Fill a 12-inch-diameter ceramic planter with potting soil containing perlite. Leave 1 inch between the brim of the planter and the surface of the soil.

Insert a lightweight trellis into the soil on one side of the planter. Push the trellis into the soil until the base touches the bottom of the planter.

Set the planter next to a very large window that receives bright, filtered light for at least seven hours each day. Choose a window with southern exposure since that orientation receives light throughout most of the day.

Sow three moonflower seeds in the soil 2 inches from the base of the trellis. Press the seeds 1/2 inch into the soil.

Pour 3 cups of water into the pot to fully moisten the soil at a depth of 1 inch. Maintain that level of moisture while the moonflower seeds germinate.

Position a grow light 12 inches above the planter. Keep the light on for eight hours every day to warm the soil and hasten germination.

Watch for signs of sprouting in 10 days. Decrease watering slightly after germination. Let the top 1/2 inch of soil dry out between waterings to keep fungus from growing on the soil.

Decrease the amount of time the grow light is on each day by 15 minutes until the plants are acclimated to the natural light conditions.

Lean the moonflower seedlings against the base of the trellis as soon as they are tall enough to reach it. Gently twine the vines around the base of the trellis to train them.

Pinch back the tips of the vines to maintain the desired height. Remove no more than a few inches from the tips of the vines each time you trim the plant.

Decrease watering by half during the autumn and winter months to allow the moonflower to enter dormancy. Resume normal watering in spring.