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. Lettuce is a fairly hardy, cool-weather vegetable that thrives when the average daily temperature is between 60 and 70Â°F. It should be planted in early spring or late summer. At high temperatures, growth is stunted, the leaves may be bitter and the seedstalk forms and elongates rapidly.ipburn is a physiological condition that causes lettuce to die back at the edges of the leaves. It results from a change in the moisture relationship between the soil and the plant. Clip off any brown leaf tissue and use the remainder of the leaf.