Q. In the spirit of Thanksgiving I was thinking about how cranberries go from bog to table, and was wondering if it's possible to grow the plants at home well enough to get a small harvest; you know: "Grow local; eat local!" I've read that they're similar to blueberries in that they need acidic soil, and are usually grown in a bog but that it isn't absolutely necessary. I am currently living in Nashville, but I'll soon be moving to Chester County, Pa. Would it be possible to grow some cranberries there? Where do you get the plants? I've never seen them for sale. Thanks,
- ---Kevin Rutledge; Nashville, TN
My old buddy Lee Reich, Ph.D. is the first person that comes to mind whenever I think of weird little fruits. Although I often reference his excellent book on pruning ("The Pruning Book" from Taunton Press), Lee is actually better known as a small fruit specialist. His classic book, "Uncommon Fruits for Every Garden," was reissued in paperback earlier this year by Timber Press, and his newest book, "Landscaping with Fruits," will be published by Storey next Spring.
So I wasn't at all surprised when Lee told me that he has personally grown cranberries in his New York State garden. Several years ago, he relates, he built what he calls a 'heath bed' (as in 'heaths and heathers') out of milled peat moss and a load of old potting soil he had on hand in which he grew a number of closely related plants: Cranberries, lingonberries, lowbush blueberries, rhododendron and mountain laurel.
All of these members of what Lee called the 'heath family' have similar requirements—a very acidic soil pH (between 4 and 5.5), lots of organic matter but not a lot of fertilizer, and a good amount of water, especially during dry times. Lee tells me that he keeps the soil acidified with pelletized sulfur and feeds the plants gently and lightly with soybean meal, an organic fertilizer of which he has an abundant nearby supply.
You can forget the 'bog' business. Lee explains that commercial "Thanksgiving" cranberries are grown in bogs mostly because flooding the fields greatly facilitates their unique style of mechanical harvesting. His cranberries grew just fine in a normal raised bed; so fine, in fact, he says he became worried that the low growing plants would overwhelm the other occupants "Luckily," he tells me, "we then had two drought years in a row; and while the other plants survived, the lack of water killed off the cranberries."
Lee rates this as 'luck' because he doesn't much care for fruits that you can't eat fresh, and cranberries (Vaccinium macrocarpon) he explains, "are virtually inedible without cooking and a lot of sugar." But he adds that the closely related lingonberry (Vacciuium vitis-idaea; also known as the lowbush cranberry), "while still tart, is delicious when fresh." Lee says he pops some right in his mouth when he's out picking and eats the rest overtop of cereal, just like the lowbush blueberries growing next to them.
But all of the aforementioned plants despise dry times to some degree, and so Lee installed drip irrigation to make sure he could continue to enjoy his beloved lingon and blueberries after the cranberries were safely dead.
"The Thanksgiving cranberry has thin stems and stays VERY low to the ground," he explains, reaching only about 4 inches in height and bearing those familiar bright red fruits in the fall. The plants are evergreen, but Lee says he doesn't care much for the purple tinge the leaves take on over winter. As he discovered, they can be rapid, productive growers when they get lots of moisture, but die off if they don't get supplemental water in dry times.
"Lingonberries have slightly thicker stems," he continues, "reach 8 to 12 inches tall, and are much more ornamental. They're truly evergreen in winter, bear two crops of berries a year—one in late summer and another in the Fall—and are edible fresh off the plant. Not sweet, mind you, but deliciously tart. The berries are a little less red and smaller than cranberries, and the plants were a little harder to establish. But once they were growing well, they survived the same drought that killed off the cranberries.
"I really want to stress how ornamental and attractive lingonberries are," continues Lee. "The plants make one of the absolute best edible groundcovers, especially when grown alongside lowbush blueberries." Blueberries, cranberries and lingonberries are all native plants as well, with lingonberries occurring naturally over a huge range: Virtually all of the Northern areas of the world! And although most enthusiasts simply harvest berries from the wild, plants are available to home gardeners. "A number of specialty nurseries carry lingonberry plants," explains Lee, "and you sometimes see them pop up for sale in nurseries in the Northern part of the country."
That last part is important; these are cold climate plants! Some lingonberry sub-species can survive in practically arctic Zone 2 conditions; and both cranberries and lingonberries require a cold winter to be productive. "Anywhere South of Pennsylvania they'd be a real challenge," feels Lee. So it's a good thing our listener is moving to the Philly area; Nashville Cranberries would be much harder to achieve than those Nashville Cats they grow so well down there.