Last year I started several dahlias indoors and by mid-spring they were blooming. However, by mid-summer it seemed they were all bloomed out. Is there a way to keep them blooming longer?

Alan, i've grown dahlias for years. They r some of the easiest and most rewarding flowers to grow. if u r from a northern climate, generally they will have a chance to bloom one time ( i know because i used to live in Vermont). I live in SC and i have had success with getting them to bloom twice. They will bloom in early summer and then the intense heat comes around the end of june thru august. During those months of intense heat i just let them go... they barely hang on, and sometimes in the case of drought we've been having,completely die down. Around the middle of august i'll cut the stalks complely down to the ground. As the days start to get cooler they come right back and around the middle of september they are flowering once again!
In the south u can leave the bulbs in the ground all year (the ground doesn't freeze),but i find that dahlias do much better when they r dug up and separated in the spring. gardendreamer03@aol.com

alan...it also helps to keep the blooms cut! It takes alot of energy for the plant to support the life of the blossom, so help it conserve its energies for repeat bloom by keeping the fully open blooms cut and in a vase or in a large float container! You probably know they keep for along time when cut. I had 72 dahalias one year! It got to the point that I had to tell my neighbors to help themselves in order to keep the blooms cut. Some I have given to nursing homes, restraunts, etc.