My head has been full of garlic lately – garlic scapes, garlic bulbils, and currently we’re knee deep in garlic harvest – but the end of July also happens to be annual brassica seed harvest time!
Last week, we pulled in a big Mizuna seed crop. Today, to celebrate the occasion we’ll talk brassicas, specifically
- Different brassica species and biennial vs. annual seed production
- Growing annual brassicas for seed
- Harvesting brassica seed
Brassica Species and Biennial vs. Annual Seed Production
The Brassicacea family (Brassicas for short) contains multiple species:
- Brassica Oleracea (broccoli, cauliflower, cabbage, some kales, and more!)
- Brassica Napus (other kales and rutabage)
- Brassica Rapa (chinese cabbage, turnips, rapini, mizuna, …)
- Brassica Juncea (spicy mustards)
- Eruca Sativa (arugula)
- Raphanus Sativus (radishes)
Each brassica will only cross pollinate within it’s own species – i.e.a B. Rapa won’t cross with a B. Juncea. As such, you can grow one type of each species side by side. Brassica seed also stores quite well. I grow enough seed of each type to last about 3 years before I will have to grow it out again.
This year I am growing Mizuna as my main annual Brassica Rapa. Mizuna is a mild Japanese green with a slight bite. It can be eaten in raw salads or stirfried but it is also great as a pickled condiment.
All brassicas can be grown as biennials (planted in late summer and overwintered to produce seed in their second year) but only a few can also be grown as annuals (leafy B. Rapas, B. Juncea. Arugula, Spring Radishes and short season Broccoli and Cauliflower). On our farm we grow quite a bit of overwintered brassicas, which also happens to mature about a month earlier than annual brassicas (see this post for our overwintered brassica seed harvest and this post about growing out radish seed as an annual.)
Growing Annual Brassicas For Seed
Annual brassicas are a lot easier to grow than biennials since you don’t have to worry about plants dying over the winter. The only trick is planting early enough for seed to mature, but not so early that plants suffer from severe cold snaps.
May 1st, we transplanted the Mizuna.
Early June, the plants were established and had sized up.
Early July, flowering was over and green seed pods were on.
Last week, the fields were drying to a nice brown. Well, except for the green weeds that exploded in the heat, despite weekly weeding. (This is a case of do as I say not as I do. Earlier this Spring, I posted on the importance of good weed control in seed production.)
Harvesting Brassica Seed
We cut the plants with secaturs and stuffed them (ever so delicately) in rubbermaid bins.
We brought in three wagonloads of bins.
And now, the Mizuna is sitting on tarps in the barn waiting to be threshed. (Not pictured in the photo are the fleet of fans on ventilation duty.)
I will wait for a nice dry sunny day to thresh the Mizuna. Hopefully sooner than later, but we’ll have to fit threshing in amidst garlic and onion cleaning and grading, the weekly seed tomato harvests, and all those other August tasks!
I’ll keep you posted on the brassica front.