Summer flower bulbs are those plants with bulbous root systems that bloom during the summer months. There are many summer flowers that with roots that are called bulbs, but are in fact rhizomes, tubers or corms. Examples of summer plants that have true bulbs are lilies and hyacinths, which can be planted in the fall. Other summer flower "bulbs," such as gladiolus and dahlias, should be planted in early spring after the ground warmed up and the danger of frost has passed.
Choose a planting site. Most summer bulbous plants prefer full sun, but can tolerate and grow well in partial shade.
Improve the soil. Turn over or till the top 12 to 18 inches of your soil. Mix in several inches of organic matter such as compost or peat moss. This will make your planting bed ideal for summer flower bulbs.
Test the soil's acidic levels with pH testing strips available at most local nurseries. Most summer flowering bulbs prefer a pH level between 6 to 7, so add lime to raise the pH or sulfur to lower it. How much you should apply depends on what your acidic results were, so follow dosing instructions carefully.
Plant the bulbs. True bulbs are planted with the tips facing up. Plant them two to three times from the top of the soil as they are tall. For example, if your bulbs are 2 tall, they should be planted so the tops are 4 to 6 inches beneath the soil. Corms, rhizomes and tubers are planted closer to the soil's surface.
Backfill the soil and be sure there are no air pockets so pack down the soil firmly with your hands or feet. Water the planting bed well. Mulch if desired, which will help retain moisture and maintain soil temperatures. Do not fertilize until after growth appears, at which time use a soluble 10-10-10 fertilizer and apply about two tablespoons per 10 square feet and reapply once a month for two more months.