The gardener who plants a crop too early runs the risk of losing the crop due to frost damage. Likewise, planting too late in the season may result in no harvest if there is an early winter. The list that follows and garden calendars provide guides for the best planting dates for vegetables. Cool-season crops generally perform poorly during periods of extended hot temperatures. Leaf lettuce and other greens BOLT and produce flowers and the foliage tastes bitter.
Peas stop producing pods.
Other crops, such as onions and potatoes, require cool weather to become established before producing the harvest during the summer months. Warm-season crops do not grow well at temperatures below 50 degrees Fahrenheit and are killed by frost. Seeds of these vegetables will often rot if planted in cold, damp soil. Not only is their growth retarded by cool weather, but also fruit set will be delayed. Crops not injured by light frost are asparagus, broad bean, broccoli, brussels sprouts, cabbage, collard, garlic, horseradish, kale, kohlrabi, leek, onion, pea, radish, rhubarb, shallot, spinach, turnip.