Planning Garden Beds: Oh, Where Oh, Where to Plant:
I like talking with neighbors about their plants — I like the sense of community, and it gives me a chance to prevent problems in my own garden. Recently, a neighbor was telling me about club root in her garden. Since I don’t want club root in my garden, her story reminds me to prevent it! Club root infects the brassicas: a long list of the plants we really like to grow here, including cabbage, broccoli, cauliflower, collards, kale, mustards, turnips, and radishes. (And the weedy herb shepherd’s purse harbors the disease—a good reason to closely manage its re-seeding!)
Club root dramatically decreases the productivity of the plant, which becomes mal-formed and susceptible to aphids and blights. You’ll notice that the plant wilts at midday and slightly recovers by morning and becomes increasingly stunted. Its leaves get big yellow spots and turn brown and in general: the plant will look just awful. Its roots are malformed and covered with a whitish growth. What has happened is that disease spores have become imbedded in the plant roots; as the roots and crown of the plant disintegrate the spores spread into the soil. These remain dormant in your soil for 3-5 years, waiting for a chance to infect other brassicas.
What to do?
Prevention: Rotate crops every year: if you had club root barely starting in one part of your garden, don’t give it brassica roots to feed on again the next year.
If you had club root: you cannot grow any of the brassicas in that spot for 3-5 years – not collards, kale, the mustards, broccoli, cauliflower, turnips, or radishes! You’ll need to pull sheperd’s purse and stray mustards!! Seattle Tilth suggests dividing the garden into thirds, rotating the tomatoes, brassicas, and squashes into a different third each year. Don’t put affected plants into your home compost; isolate them in black bags and send them away.
We can’t do much about the rain that keeps our soils so moist in the winter: but we CAN improve the drainage of our plots. By using lime we can grow in soil that’s more towards the alkaline side rather than the acid side. King Conservation district test your soil for free or you can use a kit from a garden store.
The King Conservation District http://www.kingcd.org/pro_far_soi.htm
Pacific Northwest Vegetable Extension Group (WSU website) mtvernon.wsu.edu/path_team/vegpath_team.htm accessed February 16, 2015
David Deardorff & Kathryn Wadsworth, What’s Wrong with my Vegetable Garden, Timber Press, Portland Oregon (2011) (available at the Seattle Public Library)
Kathryn True, editor, Carl Elliott and Robb Peterson, Seattle Tilth’s The Maritime Northwest Garden Guide, Seattle, Washington (2009) (available at the Seattle Public Library)