Peas are frost-hardy plants but the flowers are not. Frost-damaged blossoms can affect your crop, so plant your peas to avoid flowering during frosty periods. Depending on the variety and temperature, peas can take between seven and 11 weeks to flower. In warm and sheltered areas, peas can be sown now through July. In very cold areas, you may wish to wait till August. Seeds germinate in soil temperatures as low as 4°C and grow well in air temperatures between 10 and 16°C. You can extend the season, of course, by growing in greenhouses or tunnel houses. Peas require full sun and fertile, well-drained soil for maximum yield. Dig in plenty of organic matter before planting. A handful of superphosphate is beneficial as well.