I harvested about a third of my mustard plants today. The stack of plants is currently on a bed sheet, on my back porch, drying.
Not sure if this was smart, but it looks like heavy rains for the next two days, and I figured I’d roll the dice on part of the crop. I may have been a bit early.
The problem is that my mustard seeds are at just about every conceivable stage of ripeness, within that one stand of mustard. As shown above, for some plants, all the seeds pods have dried and shattered (left). For others, I seem to have fully-developed seeds in the pods, which is what I’m aiming for (right). Still other plants remain bloom (not shown).
As I read it, farmers have the option to harvest the plants while they are ripening, but not completely ripe. Much like tomatoes, the fruit (seeds in this case) will continue to ripen, and after a few weeks of drying, the partly-green crop is ready to be processed into seed (see Post G23-029).
You get a lot of guidance as to how the crop should look at that stage. Fully-formed seeds, with at least some already turning yellow in the pod. Most leaves already gone. Field turning from green to golden.
But what do you do if the plants are as above? Shoot for the median? Wait until they are all crisply dry (typical internet advice for the home gardener), and hope some pods don’t shatter?
So I cut down a third of it, where I’d classify the median plant as “mature green”. And we’ll see if I get any edible mustard out of that. I’ll harvest another third when the median seed pod has turned fully brown. I’ll harvest the last third when the entire stand is crisply dry.
A not-so-obvious mistake.
As I cut the plants, I noticed that the bigger plants looked a lot more uniform, with a lot larger seed pods, than the smaller plants.
That’s when I realized my fundamental mistake: I over-sowed the seeds, and grew too many plants per square foot.
Checking several sources, when grown for seed, you should ideally see 7 to 11 mustard plants per square foot. Above, you see a couple of shots of my cut mustard, with a folding rule for scale. Bottom line, my mustard plots have two to three times as many plants per square foot as is recommended. The result is a lot of small plants with ill-formed and possibly aborted seeds. And too few large plants with plump seed pods.
With 20-20 hindsight, I know what happened. My problem is that I followed the directions on the package of seeds exactly. Weighed the seeds down to the gram, and sowed at exactly the density listed on the package.
The issue? The seeds were sold as a ground cover, not as a crop. The instructions on the package were for growing mustard so densely that it shaded out weeds. And, because mustard (as ground cover) is considered a nuisance if it self-sows, no one would have given a thought to whether or not you could get edible seed if sown at that rate.
And, sure enough, now that I do the research, recommended broadcast rates for mustard-as-cover crop are about twice the recommended rates for mustard-as-seed-crop. That, and maybe a somewhat better survival rate than you’d get in a field-grown crop, and that more-or-less explains what I got.
Epilogue
The jury is still out, regarding whether or not I’ll get any edible mustard seed this year. That said, now that I know I over-sowed it, and now that it looks like most of the smaller plants aren’t going to produce seed I can use, my forecast of gallons of mustard seed has now shrunk to quarts. Or less.
At this point, I’ll settle for any reasonable amount of clean, edible yellow mustard seed.
Not a total loss, if I don’t get any clean seed this year. It was an exceptionally pretty, effective, and deer-proof cover crop. But I wouldn’t mind a bit if I got a ton of mustard seed on top of that.
