Lobelia is an annual herb that comes in many varieties and colors. The plant is low growing and is used in rock gardens, for borders and works great in planters and hanging baskets. It is easy to grow from seed or you can purchase seedlings at your local nursery. Native American smoked the Lobelia plant, at one time, as a treatment for what is now known as asthma. From that it became known as Indian tobacco. You may want to grow it just to enjoy the masses of purple, blue or white flowers from summer to first frost.
Place seeds on top of moist potting soil on a growing tray. Water from the bottom or the seeds may rot before they germinate. Start the process 10 to 12 weeks before the last frost date and keep in bright light at 70 to 75 degrees. Germination should start in two to three weeks. You can also start with seedlings, ready to plant outdoors, after the last threat of frost has passed.
Thin out the seedlings as they start to grow, keeping as many as you want to plant without crowding. The seeds are very tiny and it is impossible to plant only the seeds you will need. The seedlings are ready to plant outdoors when they are 3 to 4 inches tall and the weather permits.
Prepare your garden area by working compost into the soil where you will be planting the seedlings. This location should be in full sun to part afternoon shade.
Plant the seedlings 4 to 6 inches apart by making a hole for the roots with your finger or a thin spade. Cover only the roots and not the main stem of the plant. Water carefully with a soft spray or drip irrigation while they are small.
Water to keep the soil moist and give extra water during very hot and dry periods. Lobelia prefers cooler weather so watch that soil does not dry out when it is hot.
Fertilize with a liquid general purpose fertilizer once a month from late fall through the flowering period.
Pinch off spent blooms to encourage new blooms. You may also prune off up to half of the stems after the first flowering is over to insure more flowering by the plant.