Answer: I don't see why not. Summer flowering dahlias, gladiolus and begonias can be started in a soiless mix indoors under lights. Choose a large enough pot that will keep the corms/tubers happy until transplant time. I'd start about 4 weeks before your last expected frost date in your area (mid to end of May), and then slowly hardened them off to the outdoors before planting for the season.
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