How to Keep Cats Out of Houseplants: 10 Safe & Effective Tips Almanac.com Filtration systems Effective Water Treatment Perennials Plants The English Garden How to Get Rid of Aphids Naturally, According to Experts How to Plant and Grow Ornamental Pepper Plant your poppies when it's cold! Poppy seeds require a period of cold to germinate and grow, so they generally do best when planted in the late fall or early spring.