Monday, March 16, 2015

Brassicas on the Brain

Living in a cool climate, brassicas should be a no-brainer, right?  Sadly, I've not been doing them justice.  I brushed it off as simply not having a long enough growing season, I get what I get and don't cry about it.  It wasn't until after I posted my greenhouse plans for 2015, and read my own writing about companion planting and cabbage worms, that I thought I should really do a little research, and put more effort into the brassicas.  After all, if I can manage to harvest ripe tomatoes in an 89 day growing zone, surely there is no excuse for my brassica failures.

2015 - The Year of the Brassicas

Brassicas- Broccoli, Brussels Sprouts, Cabbage, Cauliflower, Chinese cabbage, Kohlrabi, Radish, Kale, Collard Greens, and Turnip

Companion Plants:

Helps-  Beets, onions, potatoes, cereals

Helped By-  Beets, spinach, chard, Aromatic plants or plants with many blossoms, such as celery, chamomile, and marigolds. Dill, sage, peas, peppermint, spearmint, spurrey, rosemary, rye-grass, garlic, onions and potatoes. geraniums, alliums, nasturtium, borage, hyssop, tansy, tomatoes, thyme, wormwood, southernwood, beans, clover

Growing Tips:

 Ideal temperature- 65°-75°F (18°- 24°C)

Start indoors counting back from first fall frost 120 days.

Transplant 2 to 4 weeks before the average frost date in the spring, no sooner and not much later.

All brassicas need a steady supply of water.

Organic mulch over the root zone will hold in moisture, reduce weed competition, and insulate soil against temperature extremes.

Brassicas need a soil pH between 6.5 and 7.0, high in nitrogen.

Midseason applications of fertilizer are especially helpful in nutrient-lean sandy soil.

Hand pull weeds to avoid damaging shallow roots.

In early spring, be ready to cover your plants for protection if needed. 

Summer- shade them if they need protection from the heat. 


Cabbage maggots, imported cabbageworms, cabbage loopers, and cutworms. The harlequin bug, a small shiny black insect with red markings, causes black spots and wilting leaves; control by hand picking or applying insecticidal soap. Slugs may chew ragged holes in leaves.

Marigolds repel cabbage moths. Nasturtiums repel aphids.
Tomatoes and celery repel cabbage worms.


Frosts improve flavour.

Entire broccoli plant is edible.  Harvest when the flower shoots are well formed, but before the small flower buds have opened. Timing is important, as once in flower, the shoots are woody and tasteless.

Brussels sprouts are the most cold-tolerant of brassicas, leave the plants to keep producing well into fall, sometimes after snowfall. The top is edible too; cook the leaves as you would kale.

Kale, start harvesting at the crown of the plant, removing a few young leaves at a time. This stripping of the crown encourages the development of succulent side shoots.

 After researching, I made a few adjustments to my brassica greenhouse plans, removing the carrots and adding more tailored companions.

Because tomatoes repel cabbage worms, I will start 4 cherry tomato plants to grow around the cauliflower.  Does it look crowded enough yet?  See?  I just can't help myself.  All of that wonderful goodness to squeeze into such a small space.

In addition, I'll add a few brassicas in the garden with their other companions, just to see how they fare.


  1. Wendy - i haven't had much success with the brassicas either. the year before last we just got way too much rain - most of the plants enjoyed it but where i had the brassicas planted just stayed like a mud puddle. arghghg. learned my lesson last year and just as i was starting to get proud of my broccoli, cauliflower and brussel sprouts, from out of nowhere came 9 million slugs and just destroyed the brassica bed in a couple of days!!! arghghgh! so after some research i have learned that if i staple plastic all around the beds, it makes it much more difficult for them to climb up the plastic than just up the bed. they will hit the plastic AFTER they make it past the salty sand that will be around all of those beds. dang slugs!

    your plans look very good and i am doing the same brassicas as you minus collard greens and kohlrabi. question: do you eat a lot of kohlrabi? do you can and/or freeze it for winter months?

    your friend,

    1. That's pretty much the way it went the last time I planted cauliflower. Everything was coming along beautifully, and then the sudden cabbage worm invasion all over everything! I'm still nervous to try cauliflower again, but I'm hoping the companion plants will ward off the bugs.

      Last year was the first year I planted kohlrabi. I guess I didn't water it very evenly. It all split. Very hard and woody when I harvested it, and we didn't eat it. Will try again. Collard greens will depend on if I can find seed locally, since I already placed my seed order online for this year. I think it might like the greenhouse better than kale though.

  2. I need to do the same study for zucchini, as I plan to have lots. Good job on the research.