Ripening

• Like other garden plants, tomatoes take a predetermined number of days to ripen. While the rate of maturity varies depending on the variety, most tomato plants take between 55 and 80 days from the time of planting to the beginning of the harvest season. Planting tomatoes too late in the season, especially in cool climates, often results in inadequate time for ripening.
  
  

Temperature

• Temperature extremes are a common cause of failure to ripen in tomatoes. Six to eight days of temperatures below 50 degrees Fahrenheit can result in tomatoes that fail to turn red, while extreme heat for extended periods can cause green fruit to burst before they complete the ripening process. Continued cold temperatures early in the growing season may delay the formation of blossoms, which results in late fruit set.
  
  

Sunlight

• Tomatoes require full sunlight for optimal growth and fruit production. Although tomatoes may survive in areas with filtered sunlight or partial shade, the low levels of light have an adverse affect on fruit formation and ripening.
  
  

Considerations

• Encourage tomato ripening by planting seeds indoors about eight weeks before the final frost in your area, or purchase sturdy seedlings that give your garden a head start. Selecting a sunny planting site increases the likelihood of an abundant harvest of red, ripened tomatoes. Early cold spells don't have to result in the loss of an entire crop. Picking green tomatoes before an expected frost allows you to ripen them off the vine and enjoy them. Most green tomatoes store for up to six weeks in warm, moist conditions with proper airflow.