Pushing the Boundaries: Experimenting with Seed Production on our Farm
Every year, the High Mowing Production Farm reliably produces many varieties of quality seed for tomatoes, peppers, cucurbits and some species of Brassicas. This past year we grew seed for 46 varieties including: Ali Baba watermelon, Long Pie pumpkin, Tom Thumb popcorn, Jack Straw pumpkin, Indigo Rose tomato, and My Fair Lady F1 & Bling F1 sweet corn. Although we wish that we could grow most, if not all, of the varieties that we offer, it just isn’t feasible in our region because of both our limited space and our climate. Growing for seed requires a lot of land with many isolated fields separated by at least a half mile (depending on the crop) so that related varieties can’t cross. Our other major challenge is our climate. Our cold and often damp climate can prevent some seed crops from fully maturing. Over the past few years we have started doing some smaller experiments, or test productions, to push our boundaries and continue to increase our knowledge of seed production.
Seed Crops that are Most Challenging for Us: Biennials
Producing seed for biennial crops (see our recent article on this) poses a challenge in our harsh New England climate.
Biennials such as Brassicas require vernalization—a prolonged period of cold temperatures—to trigger the plant to flower and ultimately to produce seed.
Biennial plants best overwinter in temperatures that hover near freezing. The premier climate for growing biennial seed crops is best showcased by the mild, wet winters followed by hot, dry summers of the Pacific Northwest, from where we currently source many of our biennial crops. In that region, Brassica crops such as cabbages are seeded in the fall and overwintered in the field. In early spring they break dormancy, flower and produce seed in the height of the (hopefully) dry summer when the threat of disease brought on by moisture is lessened. In any given year on our Seed Production Farm, we produce about a dozen Brassica varieties, including: Ruby Streaks, Green Wave, and Garnet Giant mustard greens as well as Asian greens such as Prize Choy, Vivid Choi Pac Choy, and Shanghai Green Pac Choy. Unfortunately, we can really struggle to get high yields out of our crop due to several factors:- Our winter temperatures can simply kill the plants, rather than vernalize them. Prolonged periods of sub-freezing temperatures such as those typical of northern Vermont, do not provide the best climate for biennial crops to overwinter right out in the field, even with row cover. Currently, the Brassicas that we plant for our seed productions are seeded in the greenhouse in very early spring. They are then hardened off and transplanted in the ground long enough to trick them into thinking that they’ve had a full winter—as long as the weather cooperates!
- We have trouble with complete vernalization and therefore have had non-uniform flowering and lower seed yields. Because of the ways that we push vernalization of our Brassicas, different plants can reach different levels of vernalization. This causes Brassica plants to flower at different times and therefore yield less seed, due to something called “self- incompatibility”—a trick that Brassicas use to decrease inbreeding—they will not self-cross, or cross with other plants that are too genetically similar. While this is a beneficial trait for the plants, it makes it even more important to have the stand flowering uniformly to maximize the opportunities for pollination.
- We can have cool, wet summers. These types of conditions can pose challenges with disease, and can make it difficult for plants to be nicely dried down for threshing.
My favorite variety, especially since it's that time of year when I'm scrounging in the winter (unheated) cloche, is Giant Winter Spinach. I've tried a number of winter spinaches over the years but none has shown the vigor of Giant Winter. Not only does it grow well but the leaves are very large so the amount of food it produces is substantial, and it's easy to wash, very tasty too. I sow it thickly in the fall here in Oregon, eat the thinnings, and then around February or so, side-dress the remaining plants with a little blood meal or a liquid nitrogen booster and it really takes off for a strong flush. It usually carries me over until the new spinach is ready. Highly recommended!