Issue: April 21, 2007
Can I harvest over-wintered turnips and collards?
We planted collards and turnip greens last year, but didn't plow them under or pull them up by their roots at the end of the growing season. Now they are about to go to seed. Can the leaves be used for greens or will they be bitter. What if I cut off the tops so they don't go to seed? Will that help?
You didn't give your location. Your location in New Mexico affects the answer to your question. In Northern New Mexico where it is still cool, you can continue to harvest and eat these crops. In Southern New Mexico, these plants may have started to bolt. That is, a blossom stalk has formed. Once the plant has bolted, the quality of even the leaves will be degraded. They will become more fibrous and develop the bitter flavor you mentioned. The turnip roots will definitely become pithy by this time. You can try harvesting them to see if the bitterness has developed or if the leaves are too fibrous.
Cutting the tops will not help. Biennial crops such as these grow as a rosetted plant during an initial growing season. This is the season we normally harvest the leaves and roots. After a period of vernalization (cold weather in the winter in the case of these crops), biochemical changes occur within the plant. These changes lead to bolting and flower production that occurs during the second growing season of a biennial. Bolting can't be stopped by cutting the tops; they will just form branches that try to flower.
At this point, many gardeners allow the plants to flower and produce seed. Some harvest the seed to plant later, others just let the plant self-sow its seeds. This practice is good if you have room and want to do it. Another consideration is whether or not the plants you were growing are hybrids (not likely with the crops you named). Seeds from hybrid plants will not produce new plants with the same characteristics and quality as the parent plants. Some of the offspring may produce good quality vegetables, others may be very poor quality. Saving seeds from hybrids is not recommended as a general practice. However, if you have the room and interest, it is interesting to see what develops when seed from hybrid plants are grown.
Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: firstname.lastname@example.org, office: 505-865-7340, ext. 113.
Please copy your County Extension Agent and indicate your county of residence when you submit your question!