How to Grow Swiss Chard Indoors

Fill a container with rich, well-drained potting mix. Choose a container at least 8 to 14 inches wide and deep for up to 3 plants. Work organic fertilizer such as compost or peat moss into the potting mix to nourish the plants as they grow.

Plant seeds 3 inches deep into the soil. Sow several seeds in your container. Though you will only keep up to 3 strong plants, planting several seeds allows you to choose among the healthiest seedlings to keep and grow to maturity.

Water the seeds, making the soil in the container moist. Soil should never become soggy or muddy, but should stay moist and hydrated at all times. Water regularly to achieve proper soil moisture. Some types of containers may require daily watering to see these results, while others require more infrequent watering.

Place the container in a full sun area. Choose either a sunny window or a sun room, or use an ultraviolet light in rooms with little or no sun exposure. Chard requires at least 6 hours of sunlight daily. Some ultraviolet lights need to be turned on longer than 6 hours to achieve the same amount of sun exposure as natural light, so refer to the instruction manual of your light for proper light schedules.

Thin the seedlings once they reach a height of 3 inches. Some seedlings may have more than one shoot coming from the base, so thin these seedlings to only one shoot per base. You should end up with 1 to 3 healthy, single-shoot seedlings spaced 6 to 8 inches apart in your container.

Harvest leaves as soon as they are large enough to eat. Youngest leaves are most tender and sweet, while harvesting from the outer leaves encourages fresh new growth in the center of the plant.