The pea is a green, pod-shaped vegetable, widely grown as a cool season vegetable crop. The seeds may be planted as soon as the soil temperature reaches 10 °C (50 °F), with the plants growing best at temperatures of 13 to 18 °C (55 to 64 °F). They do not thrive in the summer heat of warmer temperate and lowland tropical climates but do grow well in cooler high altitude tropical areas. Many cultivars reach maturity about 60 days after planting. Generally, peas are to be grown outdoors during the winter, not in greenhouses. Peas grow best in slightly acidic, well-drained soils.