Spinach grows best in the cool weather of spring and fall. Mature spinach plants can tolerate temperatures as low as 10 to 20°F (-12 to -7°C). Time spinach seed starting so plants come to harvest before or after the very warm and hot weather of summer. Hot weather will trigger bolting and seed-stalk formation. Bolting can be slowed by picking the oldest leaves first, but bolting ultimately can not be stopped if spinach matures in very warm weather. Spinach matures in 35 to 50

