how to grow carrots, with dr. john navazio

WHEN THE MOST COMMON CHALLENGE readers confessed in a recent story on vegetable gardening was “I can’t grow carrots,” I knew whom to call: John Navazio, Ph.D. to the rescue. John, who these days serves in a joint role as Senior Scientist for the Organic Seed Alliance and the Washington State University Extension specialist for organic seed for his home state, has grown—and bred—more than a few carrots in his time. John, whose dramatic and delicious purple ‘Dragon’ carrot is bright orange inside, was reassuring as ever. First, don’t feel bad, he said. “Carrots are one of the harder vegetables to grow,” confirms John (with flowering carrots in an OSA photo, above), and for a few reasons:

They’re such small plants when they first sprout (the seed isn’t too big, either; I like to use pelleted, shown below, and there are now pelleted ones that meet organic certification requirements).

To get really good quality you need “unchecked growth”—no obstacles either literal (like rocky or otherwise tough soil) or meteorological (extremes of heat, cold or especially dryness). “Succulence and flavor will suffer if the growth is checked,” John explains–and so can their shape.

Would that we all were surrounded by a true loam (meaning an ideal soil with equal parts sand, silt and clay)—but since we’re generally not, the answer, John says: compost.

“Adding lots of organic matter—not bagged products, but high-quality local compost in bulk—will help you grow good carrots, and it will also help solve problems many gardeners have growing broccoli, cabbage and Brussels sprouts to good size,” he says.

john’s carrot how-to:

  1. Plant your root crops, including carrots, in the least-rocky soil you have.
  2. The soil should have a good “tilth”—with plenty of organic matter in the form of compost incorporated.
  3. Plant early, but not too early. A 70-80F degree soil temperature is ideal, but if you are patient, and don’t mind slower germination, plant in spring once soil temps are consistently above 60F, or as the old-timers would say “once the weather has settled.” (Many gardeners stagger sowings to have fresh-eating carrots over a longer season, timing their “storage” types to harvest late.)
  4. Don’t overwork the soil; a fine powder (which can result from mechanical tilling) can crust over—and crusting=checked growth=bad news. Just work the soil enough to create a welcoming seedbed.
  5. Plant the seed ½ inch deep and don’t sow too thickly! Better to space correctly than to thin. “I’m a great believer in putting down the exact amount you need—not too little, and not three to five times too much!” John advises.
  6. Assuming you are using fresh seed or a leftover packet that has been properly stored, germination would be about 80 percent, so:
  7. “Take your time, and carefully place 16-20 seeds per foot in the row,” John says. If you have good seed, you’ll be ‘planting to stand,’ as farmers say—plant right, and you eliminate thinning time.” The successful plants will end up about an inch apart
  8. Alternatively: Plant staggered in 2½- to 3-inch-wide “bands.”
  9. Gently tamp down the seedbed once sown; don’t step on it, be gentle.
  10. Be prepared to wait 7-10 days for germination.
  11. Keep the seedbed evenly moist till the seeds emerge. Especially in clayey soils, crusting must be prevented or else!
  12. Make light, frequent sprinklings to a depth of 2-3 inches. If the seed’s tiny radicle—the embryo’s primary root—meets resistance? Death, says John.
  13. A trick to “mulch” the seedbed: “Sprinkle a very light layer of grass clippings on top of the row to keep things moist,” he says.
  14. Or the tip John likes best: Sow radish or even better turnip seed among the carrots. Both germinate extra-fast, and help break through any possible crust.—and also mark the row, since they sprout before the carrots.  “Pick the tiny plants and eat the baby leaves in salad,” he advises.
  15. If you planted too thickly and must thin (like the seedling below), do so in the first couple of weeks after emergence.
  16. Weeding is essential—early and often; ferny-textured carrot foliage isn’t much competition for weeds. Hand weed; don’t let any competition get established.
  17. Remember our mantra throughout the growth cycle: unchecked growth. The taproot of the carrot is below the carrot itself–meaning what John calls the “buggy whip” (like the one in the photo above), which can be 14-18 inches long, needs water. Soak deeply as the plants grow.

when are they ready to harvest?

DON’T JUDGE a carrot by its seed packet’s days-to-harvest number. Catalog and labels may say 65-70 days for many varieties, but “that is not my experience,” says John. “They can take 95-100ish even.” How to tell? Pull a few to see if you’ve got “tip fill” yet–at least some degree of blunting at the end, and also to taste for full development of flavor. You can eat them sooner, of course, but why waste a mouthful?

which carrots to grow?

FOR THOSE who have had trouble growing carrots, John recommends a couple of sturdy but delicious varieties to get you started:

  • ‘Parisian Market‘ types (the early, fat, rounded little guys), or ‘Oxheart’ or ‘Atlas’ don’t develop deep roots, so these should boost your confidence.
  • ‘Red Core Chantenay,’ with big shoulders, need somewhat deeper soil, but are strong growers. “They can get as big as a coffee mug around and 10 inches long,” John says. “They’re great for cooking–those are the diced carrots in every can of soup.”
  • While delicious, Nantes types (cylindrical like a cigar, not tapered) prefer better soils. they have wonderful fresh-eating flavor, so get out the compost and go for it. John recommends ‘Scarlet Nantes’ in particular.

“I’ve put a lot of thought into how to build a better carrot,” says John, who now has his sights set on breeding carrots with strong, vigorous tops that will outcompete weeds more successfully.  “That will be a really key breakthrough for organic agriculture.”

about the organic seed alliance

THE ORGANIC SEED ALLIANCE, a nonprofit started 10 years ago, “advances the ethical development and stewardship of the genetic resources of agricultural seed” through education, advisory services, and research programs with organic farmers and other seed professionals. In his role there, John Navazio strives to foster regional seed independence through participatory breeding projects with farmers, aiming for what he calls “farmer-centric seed systems” that select for germplasm well-adapted to each particular area.

The OSA blog is a great place to keep up to date on developments in the politics, and science, affecting our seed supply; the “advocacy” section of the OSA site suggests tactics for expressing feedback to government agencies and others about developments (such as transgenic/GMO sugar beets) that threaten our organic seed resources.

You may recall I shouted them out last year in a story about why I purchase organic seed when available—and how the OSA site provides a list of suppliers of organic seed.

John’s upcoming book, “The Organic Seed Grower: A Farmer’s Guide to Vegetable Seed Production,” will be published by Chelsea Green in August 2012.

carrot how-to on my radio podcast

HOW TO GROW CARROTS was last week’s topic on my radio podcast on WHDD, the nation’s smallest NPR affiliate. You can stream it here, or subscribe on iTunes (it’s the March 12 show) or the Stitcher app.

32 comments
March 15, 2012

comments

  1. says

    Great article. Here in western washington, it’s rare to reach a soil temperature of 80F at any time consistently. more-so we worry about wetness, if the soil is dry enough and workable in early March, then you can plant carrots, even if the average air temperature is between 40 and 50F. Raised beds are the best for making sure your soil is rock-free and your drainage is good. The worst is putting in all the effort only to have your veg or seed rot in wet soil.
    The other challenge I have faced is slugs, they chew holes right into the tops and the drill through the cores of your carrots until they’re ruined. My ducks won’t eat the carrot greens, though, so I let them do a good sweeping of the carrot patch each day and it reduces slug damage.

  2. Mathew says

    This is a great article! I’ve had years with great carrot growth, and other years where it seemed my seeds barely germinated. Looking back, the better crops were ones where I took my time and planted carefully instead of pouring a row of seeds too thickly and expecting them to thrive, based on results from years where I’ve been more meticulous.

    I actually didn’t realize carrots were considered a challenge, and so now I feel more confident that it’s me – not the seed – that is the issue. I had assumed in poorer years that the seed was probably of lesser quality (being heirloom seed).

    This year I have four carrot varieties going in my garden: Parisienne (a first time for me), Amarillo (my favorite), purple Dragon, and Berlicum 2 (first time for these, also). I had planned on four rows of carrots in my 4×9 raised bed, but the onions took up more room that I anticipated, and I need to leave room for at least two rows of beets, down from the three I initially planned.

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