Terroir of the Turnip

Wine lovers seem to care a lot about “terroir“, or the patch of land on which the grapes used in making their wine were grown. You could have two wines that use the same grape varietal, same vineyard management techniques and the same production methods, yet one will sell for ten times the price of the other. Why? Because of the difference in taste imparted, thanks to the terroir. So then why doesn’t terroir matter for other foods, like turnips?

Ok, maybe it sounds ridiculous to use a fancy term like terroir with such a lowly vegetable. But even if the taste differences aren’t all that apparent, what about nutritional value?

Stephanie Seneff, PhD. recently published an article about sulfur deficiency, in which she hypothesizes that one reason Icelanders have such low rates of depression, heart disease, diabetes and obesity is related to their consumption of cabbage, beets and potatoes that are grown in Iceland’s sulpher-rich soil (which comes from centuries of volcanic activity). Could Americans’ health problems be related to lack of nutrients in our fruits and vegetables? Wouldn’t it also apply to meats, eggs and dairy, since they all come from animals that ordinarily would be consuming nutrient-rich grasses?

I pondered all this on Sunday while admiring a beautiful display at one of the largest stands at the Dupont Circle farmer’s market. This stand offers an impressive variety of leafy greens – all picked and prewashed, for $11/lb.  I’ve purchased their baby arugula many times and two things have always struck me about their arugula. First of all, it’s very mild – almost sweet. It lacks that nutty/peppery/zesty “zing” that arugula can sometimes have. Secondly, their arugula lasts a full week in my refrigerator before showing any signs of age. So this weekend I asked the grower about how they grow and fertilize their crop. Our conversation went as follows:

  • Grower: [showing a picture of the farm] Here are our greenhouses, the lettuce plants are grown here on these rows. For fertilizer, we typically use 10-10-10.
  • Me: That’s a chemical fertilizer that only provides nitrogen, potassium, and phosphorous. How do you replenish all of the other nutrients that are lost when you harvest the plants? Like the minerals, beneficial microorganisms and fungi? Do you rotate animals onto the land in off years or add compost or manure?
  • Grower: No, we don’t practice organic farming, but we do turn over what’s left at the end of the year, into “green compost.”

I was stunned. After all these years of buying their premium-priced lettuce, thinking that I’m actually getting the nutrients that the USDA tells me I should be getting from this vegetable, only now do I realize that there’s no way I could be. Because every time they harvest the arugula, they are depleting the soil of calcium, magnesium, iron, etc that the leaves take with it.  If we assume that 60% of the plant is harvested then turning over what’s left only puts ~40% of those depleted minerals back into the soil. Do this for 5 years and you’re left with less than 3% of the minerals that were there before you planted your first crop![1]

Disappointed, I reluctantly walked over to a neighboring vegetable stand and asked the same question. Thankfully, this answer was different. The farmer went on and on about various types of natural mineral amendments, compost and manure they use and how they don’t use any chemical fertilizers. “We’re too small to be able to afford organic certification, but the methods we use are better than you get with most certified organic,” he told me. Same with the next stand I asked. One even told me about a special organic fertilizer that’s made of seafood products! I thought to myself, “Why isn’t this guy advertising this fact?? He should at least have a sign or something!”

Hypothetically speaking, let’s say you’re at the farmers market next weekend and there’s a stand selling turnips. You approach the farmer who tells you the following:

  • My farm’s about an hour from here, in [blah-blah city], at the north-facing base of the [blah-blah] mountains, where we have the perfect conditions for growing this variety of turnips. The climate is mild,  the soil drains well and is rich in [blah-blah] minerals from years of [blah-blah geological events], which imparts a unique flavor that you only get from our turnips.  Sure, you can put them in your vegetable soup, but personally I prefer to eat them raw in a salad, shaved paper thin, tossed only with olive oil and sea salt.” 

Then let’s say you tasted one and noticed a difference. Would you be willing to pay triple supermarket turnip price for these special turnips? I know I would!


[1] I’m sure that my numbers here are inaccurate, as I don’t know exactly what percentage of the nutrients go into the leaves versus staying in the roots. Also, I don’t know what percentage of the total nutrients in the soil a single crop extracts. I suspect it depends on the type of crop, plant spacing, root depth, tilling depth and maturity at harvest. But even if my numbers are off, there’s no doubt that the general trend of year-over-year nutrient depletion still applies.


5 comments on “Terroir of the Turnip

  1. Debbie says:

    So are you still going to buy produce from the first grower with whom you talked?

    Thanks for your thoughts on this. I never thought about how the soil itself affects the taste of food, but makes total sense.

    • Nevra says:

      Good question Debbie. No, I don’t plan to buy from that stand anymore. I’ll buy the arugula from one of the organic stands, which means I can’t be so lazy and will have to wash, dry and chop it. But I’m sure I’ll be eating many more “nutritionally empty” salads from similar farms. Probably every one I am served in a restaurant, unfortunately. Sometimes I feel like Michael Pollan, where the closer I look at where my food comes from, the more surprised I am. But I’m thankful for the few good food sources I’ve found over the years. I think that if I and other peole continue to ask questions of those that grow, distribute and sell our food, and if we “vote with our dollars” by paying the extra few bucks for the more nutritious product, that we can not only help those producers stay in business, but hopefully create a market for additional producers to enter the market so that we have more options.

  2. Anita says:

    Wow, I just bought arugula at the Dupont Market myself, so I’d love to know the names of the stands you talked to so I can go to the “right” one next time! 🙂

  3. Rick N. says:

    Nice blog Nevra. Keep it up the good work!

  4. Jason says:

    Wow, $11/lb for low-nutrient greens. Makes me want to look in what I think is good food when it might not really be. Nice research!

    A tip for washing lettuce and other greens: I often think the “best” way to wash them is in a sink full of cool water. However, we have one sink and even if it doesn’t have a few dishes in it, it usually is dirty (raw meat, eggs, etc) and needs a serious scrubbing and a spray of diluted bleach to sanitize it. The solution I’ve found is to have a small plastic tub, sold as a “dish tub”, about 9″x12″, and use it only for washing vegetables. One or two fresh rinses (rinse, empty tub, refill and rinse again) usually is all we need. If I’m storing it for a while, I lay the greens out on a clean kitchen towel and gently blot dry, or a salad spinner would work well but we don’t eat raw greens enough to warrant using one. A salad spinner with a removable spinner basket could also double as the rinse tub.

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