Honeydew melons need soil temperatures of at least 80 deg. to germinate, then they need at least 3 months of warm to hot weather to ripen fruit. This time of year, you may be better off growing them in a warm greenhouse.

Mangoes need much the same treatment, but are, of course, an investment for the future. A potted one usually takes at least 5 years to fruit, assuming it is one of the few self-pollinating varieties, and may never fruit under houseplant conditions.