The exception is one study in the Netherlandsâthe Netherlands Cohort Study on Diet and Cancerâin which women (but not men) who had a high intake of cruciferous vegetables had a reduced risk of colon (but not rectal) cancer (12).
Crops: beans, celery, corn, cucumbers, New Zealand spinach, and summer squash. Temperatures: Tender vegetables grow with daytime temperatures above 55Â°F, and are intolerant of frost. When to plant: 1  Based on soil temperature, refer to Table 2.2  Soil is adequately dry to work.3  These crops may be planted (from seed) around the date of the average last spring frost.emperatures: Very tender vegetables are not only intolerant of frost, but also cool spring winds. They need daytime temperatures above 60Â°F, and prefer temperatures of 70Â°F to 95Â°F. A week of daytime temperatures below 55Â°F may stunt the crop.
Lettuce is a cool-season crop that grows well in the spring and in the fall in most regions. Lettuce seedlings will even tolerate a light frost. Temperatures between 45 F and 65 F are ideal. Garden lettuce is far superior, in both taste and vitamin A content, to supermarket brands. Because lettuce grows quickly, the best approach is to plant a small amount at a time, staggering your plantings. Find more tips for planting delicious lettuce here.