I have debated saving some seed from my cabbages this year. Debated because cabbage seed is a weird thing. Some will cross readily and some will not. Some are annual and others are biannual. Either way, they make tiny okra pod looking things that you wait for the plant to die back and the pods to get crispy. That is the long and short of saving cabbage seed.

Cross Pollination

Now, I have not done a bunch of seed saving. My garden is small after all. This is doubtfully the end all, be all of seed saving posts but I do know a few things about saving cabbage seed as a home gardener. The first of these challenges is not to grow some mutant cabbage by planting and allowing to flower species that are too close to each other.

A general rule of thumb requires you to pull out your Latin to English dictionary or kidnap you local Catholic priest. After securing your prisoner, look up on the seed packet the Latin name of the plant you are growing.

In my case we have:

• Brassica Rapa- Suzhou Baby Bok Choy
• Brassica Oleracea Gongylodes – Early Purple Vienna Kohlrabi
• Destiny Hybrid Broccoli.
• Brassica Juncea – Florida Broad Leaf Mustard
• Brassica Oleracea Var Capitata – Early Golden Acre Cabbage

Hybrids Side Note

Now you might be asking why not include your broccoli in the Latin game we are playing. This is simple. Anything that says hybrid do not save the seed. Because a hybrid is two heirlooms mixed for superior characteristics, they are not genetically stable and do not breed true. It will be a crap shoot about what will come out of that mixture. It can be a fun experiment but not something you want to do for something that is critical to your garden. I tend to focus on opportunity costs savings in my garden to justify its existence. Playing that way tends to decrease that value.

So no hybrids but what does the Latin tell us. First, it tells us that we are playing in cabbage land. Brassica is cabbage. It’s Genus in botanist. If this is some other value, you don’t have to worry about cross pollination as much as a practical reality and as a absolute fact in a perfect world. We don’t live in perfect.

Back to the Show

Next, we have the species. This means there is a pretty good chance you won’t have cross pollination so long as it is different. If it is the same then it is the same plant. Under this scenario, we have the Kohlrabi and Cabbage to be concerned about. They are both Oleracea. They will crossbred so only do one set or the other for seed. You do both and you will be unhappy.

If you must do both then try to hand pollinate and bag the flowers. Cabbages can wind pollinate so try to separate as best you can.

While inter-species breeding is possible, this will at least give you a rule of thumb to run by.

In The Real World with Seed Saving Cabbage

I was reading a paper out of New Zealand about cross pollination in Cabbages. From their findings, the Oleracea are largely resistant to contamination from other cabbages and in this case radishes. Less than 5% seed set on foreign pollinated flowers in the most ideal setting. Don’t worry too much about the radishes, while they can do it, they are highly unlikely to do it without you purposefully playing the Island of Dr Moreau.

The Juncea is the most accommodating to everyone.

Rapa and Napus, one that I am not growing this year because it is rapeseed, are functionally the same species and will readily cross pollinate.

Now their findings were hand pollinated, under lab conditions so it is not likely that bad in the real world. Also the hybrid seed is significantly less viable and smaller than the same species seed. Remove the smallest seed and you will get most of the bad seed out.

Unfortunately distances to prevent cross pollination are difficult to impossible for home gardeners or even many homesteaders. I have seen ranges from a quarter mile to over 3 in order to keep purity. Basically, even if you grow only one seed, your neighbors could screw you in your seed saving attempts. I saw a 2014 presentation about Quarantine zones from Washington State. It makes seed saving sound impossible.

It is possible. People have been doing it for thousands of years.

Genetics

One thing that many home gardeners are probably not thinking about is inbreeding. You can’t just grow a couple of cabbages and let them go to seed and think that is sustainable. Yeah, it will work for a few generations but bad things will happen eventually. You are turning a family tree into a family shrub after all. To create stable genetics you need a slight bit more than 2 or 3 plants. Lets say something like 80-100.

Now, I don’t know about you. I don’t have space to allow that many plants to go to seed and do anything but produce seed. How is a small gardener going to handle such problems?

Don’t gnash your teeth, remove your sinning hands or anything biblical. Your initial seed packet probably has your solution. What you want to do is plant out your initial round of cabbage over the next few years.

The Seed Saving Cabbage Genetics Plan

First you are going have to dedicate a significant chunk of your garden to save seed for the long term. Save 16 plants per year for 5 years from that initial packet. That will give you your 80 plants worth of genetics.

Notice how you have not replanted any of your child seed over 5 years. In year 6 you want to grow out 8 from year 1 seed and 8 from whatever will grow from the initial packet. The initial packet seed will be old but you should get some germination if you have stored your seed properly. You want to keep having half of your seed plants from the packet for as long as possible. It will run out and you have your baby seed to rely upon. In this example, lets say you get 7 years from your initial seed before you run out.

After the initial packet. You want to push out each year in cycle as half the of a specific year and 2 plants per year on the 5 year rotation to keep your 16. You want to plant out your oldest seed to use it up for food.

Will this keep you seed saving cabbage forever?

Honestly, I don’t know. It should go a really long time, if not forever. You have the number of plants required for stable genetics. You are just not breeding at the same time. Each one of your generations are mixing every year. Nothing says they all have to exist simultaneously. We just need them to swap genes on regular.

That is my best theory on how to save seed when you need so many plants. I intend to setup a test garden but need to figure out the model to gauge success.

That all I got to say about that. I feel a strange urge to offer you a chocolate.