The Brassicaceae Family — it’s all about the planning

plant profile

Within the large, extended Brassica family are many veggies that may not seem related, but that are, in fact, descended from a common ancestor. Members include many of the most popular vegetables — broccoli, kale, collards, turnips, mustards, cabbage, and radish. When you stop to consider the varieties that exist within those groups, you get a sense of this family’s enormity.

Of all the plants from which I have saved seed, cole crops are — from a labor standpoint — among the easiest to harvest. But that doesn’t mean saving their seed is easy. On the contrary, cole crops require a bit of forethought before your plants begin to flower.

The greatest challenge to the gardener is knowing which species their plant belongs to. This is crucial because plants within the same species will easily cross with one another, producing hybrid seed that will be worthless the next year. Unfortunately, most of the brassicas that gardeners like to grow come from the same species, Brassica oleracea.

Brassica oleracea includes broccoli, Brussels sprouts, cabbage, cauliflower, collards, kale (excluding some types of Siberian kale), and kohlrabi. If you’re like me, then you generally plant at least two members of this species during a given season.

steps for saving seed

  1. The first step in saving brassica seeds is to decide what type of plant you want. Let’s say your garden contains broccoli, collards, and kale, and you especially want to save kale seed.  Eat from all three varieties throughout the spring, but  don’t decimate one kale plant. Rather, pick leaves from each  in order to spread the harvest among all.
  2. As temperatures increase and your plants begin to flower, remove your broccoli and collards.
  3. Unlike other species, many cole crops are self-incompatible, which means that good seed production will depend on having multiple plants available for pollination. Some resources recommend having a minimum of 6 plants. I find that 4 works well for the small gardener. If you’re growing on a larger scale, you may want to have as many (or more than) 20 plants. The more plants you have, the better the quality of your seed.
  4. Soon, your plant will put forth seed stalks and small yellow flowers (Cole plants used to be classified as Cruciferaes because the flowers form small crosses). After the plant has been pollinated, it will produce a series of elongated seedpods. You must allow the seeds to mature while the plant is alive. Mature pods will dry and turn a light brown. They are then susceptible to shattering.
  5. Once the pods are mature, carefully remove the plant from the ground and allow it to cure for a few days. I usually place a mature plant upside down in a five gallon bucket.
  6. After the plant has cured, shake it in the bucket which will shatter the pods and release the seed. You can also shatter the pods by hand. Another technique is to shatter them over a white sheet.
  7. Finally, winnow the seed from the pods, store, and save. Sometimes, if you time it right, you can plant spring’s seeds for the fall garden!

tips for cole crops

  1. I wrote the steps above for those who have limited space and/or time. If you want to grow multiple plants from the same species and save seed from each, the surest way to avoid crossing your plants is to cage them. In this scenario, you expose your kale plants for a day or two while placing your broccoli and collards inside cages with wire mesh that is small enough to prevent bees, wasps, and other pollinators from entering. Then cage your kale and collards and un-cage the broccoli. Repeat these steps until all plants have been pollinated. Although this is a more time- and labor-intensive method, it is the only workable option if you are gardening in a confined area.
  2. My Cole crops have always had problems with insects — from aphids, to cabbage loopers, to leaf miners, to cutworms, all creatures seem to find the mighty brassica tasty. One option for dealing with this problem organically is to plant a catch crop. Catch crops are those which farmers plant to draw the bad bugs away from the crops they want protected. In my experience, mustards make a great catch. I don’t know why this is. Perhaps the bugs enjoy the tang of a mustard as much as I do.
  3. Brassicas are heavy feeders. Make sure that you have a good supply of fertilizer to keep them happy.
  4. In some parts of the country, the climate is mild enough that you can overwinter certain Cole crops. When planted in the fall and allowed to get established, they will become dormant during the winter. Then, early in the spring, you will have veggies far ahead of most other people. Champion collards and Purple Sprouting broccoli were two varieties that worked well for me. Unfortunately, Kentucky winters are too harsh for overwintering without the aid of a greenhouse or other cover.
  5. Saving cabbage seed can challenging because, as with head lettuce, the seed stalk sometimes has difficulty piercing the head. Some farmers rap the head with their palm or slit the top to help the seed stalk emerge.
  6. Because the Brassica family is so large, crop rotation becomes a little trickier than with other plants. For instance, growing radishes, broccoli, and turnips in the same bed will attract the same insects and allow the for the build up of damaging bacteria in the soil. When planning your garden, be aware of the many different members of the Brassica family and try to rotate in non-Brassica crops every 2-3 years.