Summer 2011

By Will Bonsall

When I was a kid, I really loved turnips, even though I had never tasted one. Oh, I thought I had; didn’t we use turnips in that traditional New England Boiled Dinner we had on special occasions, along with corned beef, carrots, beets, potatoes and so on? Sure, turnips were an old Maine favorite, but I didn’t learn until years later that they weren’t really turnips – they were rutabagas!

Of course, any word means whatever we decide it means, but it’s confusing when other people don’t mean the same thing – which is why Carl Linnaeus came up with a system for classifying living things, a system that ignored “common” names in favor of “specific” groupings. There was a real need for such a system, and the “turnip” is a classic example of that need.

Crossing Species

One species of plant – Brassica rapa – that everyone agrees to call “turnip” (in English, that is) is native to central and southwestern Asia, so both wild and feral turnips grow in those areas. (Ferals are domesticates gone wild, whereas true wilds never were domesticated.) All interbreed freely. Those true turnips have spread all over the world with the diffusion of agriculture. And they all have 20 chromosomes. Hold that thought.

Another species – Brassica oleracea – grows wild in the coastal regions of Europe. It is commonly called sea kale and is the ancestor of our modern “true” kales, as well as cabbage, kohlrabi, cauliflower, broccoli, collards and Brussels sprouts. Notice the “col” root in most of their names. These are merely botanical variants of the original weed. All B. oleracea, wild or domesticated, have 18 chromosomes.

Those two different chromosome numbers mean that the two are separate species and will not ordinarily cross. But ordinarily is not the same as never, and at least once – probably sometime in the 15th century – that is exactly what happened. Presumably some Baltic farmer’s turnip field was adjacent to the wild and weedy sea kale, and even at one-in-a-million odds, numerous cross-pollinations occurred over the years, some resulting in fertile seed. Ta-da! – the rutabaga.

The name used in North America, incidentally, comes from the Swedish “rotabagge,” meaning “root bag.” The Brits call them “Swedish turnips” or just “Swedes.”

And the chromosomes? Rutabaga has 38, which means that whereas crosses between the two parent species are extremely rare, the offspring rutabaga cannot possibly backcross with either. It is a new, albeit synthetic, species (Brassica napobrassica), and to my knowledge, no feral rutabagas exist; there certainly are no wild rutabagas and never were. Sort of like triticale, beefalo and mules, although the latter cannot make fertile offspring.

Saving Seed

This knowledge is useful if you want to save seed – which you should, unless you enjoy depending on strangers for your basic necessities.

Both true turnips and rutabagas are biennials, which means that some of their roots must be overwintered in a cellar or refrigerator drawer to be replanted outdoors in early spring, after which they’ll go to seed. Then any varieties of the same species must be isolated from each other by several hundred feet to maintain varietal purity. That is, two rutabaga varieties must be isolated from one another; and two turnip varieties must be isolated. However, if you have one variety of each species, then forget about isolation. You can save seed from both ‘Early Milan’ (true) turnips, for example, and ‘Waldoboro Greenneck’ turnip (which is actually a rutabaga) planted in close proximity with no fear of crossing.

Growing Rutabagas: Sow in Summer

Some people actually don’t care for the flavor of rutabagas. Obviously those individuals do not have souls. This is not just my ornery opinion; scientific studies have shown that certain people are allergic to the compound glucosinolate, which, I imagine, is essential for the normal development of the soul. Assuming that you are a morally upright person who eats rutabagas (and likes them), I will give you some tips on growing them.

Whereas true turnips are grown either as spring or fall crops, rutabagas are really only suitable as a fall crop, because they need a longer season to reach their greater size. Also, although the young plants tolerate hot, sticky midsummer weather, when the taproots begin to swell, they prefer cooler, moister weather to size up quickly without going woody. Moreover, preharvest frosts make the flesh sweeter and more tender.

Pest control is also simplified by later planting. Flea beetles do not get such a head start on later plantings – indeed they can be avoided altogether – and root maggots are not so active later.

By late planting, I mean between mid-June and the Fourth of July. Sowings after this will yield smaller roots, but that’s not the end of the world. A well-grown rutabaga may feed your whole neighborhood, even assuming all your neighbors have souls, but smaller ones can be just as nice.

Rutabagas, like other cruciferae, don’t much care for fresh animal manure under them (nor do I, frankly), as it encourages clubroot and other diseases. In fact, I prefer well-rotted veganic (plant-based) compost or green manure for healthier root crops in general. My favorite is shredded tree leaves, shallowly tilled in the previous fall. Their abundant calcium, magnesium and potassium are well balanced with adequate nitrogen, all slowly released throughout the season.

Boron deficiency can be a problem, especially if, like me, you don’t routinely import amendments onto your land, and if the soil is naturally lacking in this micronutrient. (Maine soils vary greatly in this respect.) A deficiency typically results in deformed roots with cracked, hollow or brown interiors. If you suspect such a problem, boron is easy and cheap to add; indeed, don’t overdo it. Five to 10 pounds per acre should be ample; better to use too little and adjust it next year.

I add boron as calcium tetraborate, or borax. Older readers may recall Ronald Reagan when he peddled Twenty Mule Team Borax on “Death Valley Days.” That’s the stuff; no detergent, just borax powder mined from a dry California lakebed. Once added, boron should continue to cycle in the soil indefinitely, unless it is lost from your system by water erosion or that most pernicious form of soil depletion: marketing crops.

If flea beetles are a serious pest for your crops, several products can counter them. However, I’ve discovered an effective home-grown remedy: I pull rhubarb stalks and prepare them for the freezer, saving all the leaves and flower stalks. These I chop into a 5-gallon bucket, cover with a little warm water, and bash with the end of a wooden baseball bat. Then I add more water and let the mix sit in the hot sun for a day or three. I strain the liquid through a cloth and fill my backpack sprayer with it, adding more water if necessary.

On a still, sunny day, I spray the young plants with a fine mist – not so much that it beads up and runs off – and let that dry. Two or more sprayings are usually required to make a thin glaze of oxalate on the leaf surface. If there’s much rain, I have to apply the spray again (I’m sure any kind of added “sticker” would be useful here), but often by the time that happens, the plant have outgrown the danger. Early response is critical with flea beetles, lest they weaken the tiny seedlings. [Ed. Note: Homemade products used to control pests are considered unregistered pesticides when the EPA has not established a tolerance level for them. See “BPC Adopts Policy on Homemade Pesticides” in the March-May 2011 MOF&G.]

Rutabagas don’t tolerate weeds well; frequent but shallow cultivation is well rewarded. Better yet, do an initial hoeing and thinning, followed by mulching a day or two later. Not plastic mulch – that’s really perverse – and preferably not hay nor straw, which takes forever to apply, especially since my rows are only 18 inches apart and plants are thinned to 6 to 8 inches within rows. The best mulch for such closely spaced crops is shredded leaves from deciduous trees. I prefer maple; use what you have. They come out of my shredder looking like cornflakes or confetti.

They’re extremely quick and easy to apply – I just fill a large rubber trash barrel and walk down the path with it on my shoulder, strewing a blizzard of confetti over the whole bed, plants and all. Assuming the plants are at least 2 inches tall, the mulch settles neatly around them, leaving no bare spots. Compared with hay mulch, a relatively thin layer of leaf confetti will settle into an impenetrable weed barrier through which moisture can enter more easily than it can escape. The fluffy carpet also prevents soil compaction, even where you must walk, and keeps the earth consistently cool, which brassicas love.

Compared with crops such as beans and tomatoes, rutabagas display little obvious variation – I suppose because they’re a relatively new species and would have shed a lot of the parent species’ gene pool in passing through the window of speciation. I’m particularly aware of the lack of diversity, since I curate the rutabaga collection for the Seed Savers Exchange (SSE). Although the SSE has only a few hundred accessions (compared with thousands of beans or tomatoes), its rutabaga collection is one of the largest of its kind.

Rutabagas inherit the swollen taproot and pungent flavor of their turnip ancestry, and the milder, sweeter taste and smooth blue-green foliage of their wild kale forebears. As a rule, rutabagas are yellow fleshed, owing their high carotene content to the kale side, whereas turnips tend to be white fleshed. There are, however, a few white-fleshed rutabagas and a few yellow-fleshed turnips.

In the past century, rutabagas have been improved greatly through selective breeding. Indeed, one of the hallmarks of the old heirloom varieties (such as ‘Gilfeather’) is their rougher texture, inside and out. They were often grown primarily for livestock, whereas more modern sorts have been refined for the table, ridding them of side roots and irregularities.

Do I have favorite varieties? Perhaps, but I tend to change my mind from year to year, and I haven’t given most a fair trial – but I never met a rutabaga I didn’t like. The good news is that you can access dozens of rutabaga varieties, including all I currently have to offer plus many others, in the annual yearbook of the Seed Savers Exchange (, or SSE, 3094 South Winn Rd, Decorah, IA 52101). Still other varieties are in the Garden Seed Inventory (also from SSE), which lists all vegetable varieties offered by U.S. and Canadian commercial sources. You can grow and rate these for yourself, but just remember: They’re not really turnips!

About the author: Will Bonsall lives in Industry, Maine, where he directs Scatterseed Project, a seed saving enterprise. His extensive, bountiful and beautiful gardens are open for tours two days each summer. Dates are listed in the “Daytripping” feature in this MOF&G. He is also a favorite speaker at the Common Ground Country Fair, and author of Through the Eyes of a Stranger, Yaro Tales Book One, available from Bonsall at 39 Bailey Rd., Industry, ME 04938.

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