If you're looking for an easy way to add a spark of color to your flowerbeds, lobelia can fill the bill. Lobelia is easy to grow and is happy nearly anyplace, including borders, rock gardens, hanging containers or as a ground cover. Start lobelia seeds indoors about two months before the last expected frost for your area.
Fill several 2-inch pots with commercial potting mix. Scatter a few of the tiny lobelia seeds on the soil, and press them lightly into the soil with your finger.
Spray the soil with a fine mister, and cover it with a piece of plastic wrap. Put the trays or pots in a warm place in indirect sunlight. If you live in a cloudy climate, a grow light is the best way to ensure the seeds get enough light to germinate.
Check the soil daily, and if it appears to be getting dry, mist it lightly. Don't overwater, because excess moisture can cause the lobelia seeds to rot.
Remove the plastic when the seedlings emerge from the soil, but leave them in a warm spot or under a grow light until you're ready to plant them outdoors. When the seedlings are about 2 to 3 inches tall, thin them to one seedling per pot.
Choose a sunny spot to plant the lobelia seedlings. Although lobelia will grow in partial shade, it will bloom much more in full sun. Remove weeds from the planting site, use a hoe or garden fork to cultivate the top 8 inches of soil, and mix in a scoop of compost.
Plant the lobelia, leaving at least 6 inches between each seedling, and water them with a hose and spray nozzle. After the lobelia blooms for the first time, feed it a water-soluble fertilizer, following the manufacturer's directions. Water the lobelia every other day in hot, windy weather.