Pot up tender summer bulbs such as tuberous begonias, cannas, and dahlias to get a jump on the season. Here are five tips from the Netherlands Flower Bulb Information Center for starting bulbs indoors:
1. Select bulbs that are firm to the touch.
2. To get earlier blooms, plant bulbs in pots about six weeks before you plan to plant them outdoors. Choose clean containers with drainage holes. Use a commercial potting mix blended with equal parts peat moss and a drainage material such as sand or perlite.
3. Place bulbs in the potting mix, following planting directions. Different types of summer bulbs require different planting methods.
4. Keep soil moist, but not wet. Warm, humid settings are ideal for growth. Bulbs won’t need any light until they’ve sent up sprouts. Then you can place bulbs in a sunny window. 
5. Plant outside only when the threat of frost has passed.

Photo courtesy of the Netherlands Flower Bulb Information Center.