Growing nasturtiums from seed is the perfect project for the beginning gardener. They are easy to grow and require very little care. The child gardener will particularly enjoy the fact that the entire plant is edible: leaves, flowers and seeds. There's a variety of nasturtium for every gardener, from the dwarfs for container-growing, trailing varieties for hanging planters, and vining varieties to train on a trellis. Plant your nasturtium seeds after the last frost. If you plant in early spring you should have blooms through the fall. Nasturtiums are hardy in USDA zones 9 to 11.
Soak the nasturtium seeds overnight in water.
Locate an area of the garden that gets full sun all day. Amend the soil in the gardening area by adding a 3-inch layer of sand to the existing soil. Mix it in well and water deeply. Allow the soil to drain.
Plant your nasturtium seeds 1 inch deep and 5 to 10 inches apart. Cover the seed with soil.
Water the planting area frequently to maintain a moist soil. Your seeds should sprout in one to two weeks. At that point, water them weekly, but more often during periods of excessive heat.
Fertilize your nasturtium only if the soil is deficient in essential nutrients. Fertilizing the plant promotes leaf growth but limits the number of blooms on the plant.
Check the plants frequently for infestations of aphids, caterpillars, spider mites and whiteflies. If you plan on consuming the nasturtiums you will need to use an organic insecticide, such as Neem Organic Insecticide, to treat infestations.