“Growing vegetables is a fun introduction to gardening,” says Sullivan. They don’t take as long to grow, so if you make a mistake you won’t have wasted months and months of your time. Sunflowers are also a good option, since they grow quickly and tall, or try easy-to-grow ferns—both of these can be grown all across the United States. “Early success is inspiring,” he says. “It will make you want to start planting more complicated plants. Have fun with it!”