While large cranberry farms in the northern U.S. and Canada utilize man-made wetlands to grow this tart fruit on a commercial scale, you might be surprised to learn that, with a little effort, you can grow cranberries on your farm, too.
Choosing Your Cranberry Crop
Because they need a set number of chill hours to set fruit, cranberries are a perfect fit for gardeners in USDA hardiness zones 2 to 5. They require cold winters and acidic soil to perform their best.
Begin your cranberry-growing experience by deciding which type of cranberries to grow:
- North American cranberries (Vaccinium macrocarpon) are the classic cranberries used to make juice and Thanksgiving cranberry sauce. They’re extremely tart and are best eaten when combined with sugar or another sweetener. Good varieties include heirlooms, like Howes and Ben Lear, or the hybrid Stevens, which has increased productivity and disease resistance.
- North American low-bush cranberries (Vaccinium vitis-idaea var. minus) are another option. Also known as lingonberries, the low-bush cranberry isn’t nearly as tart and can be eaten fresh off the plant. Lingonberries tend to be more popular in the Pacific Northwest, though they’ll grow in any northern climate.
Cranberries are high in vitamin C and antioxidants and are low-growing, vining shrubs with runners that trail along—or just beneath—the soil surface. The plants also form upright branches on which the flowers and fruits are produced.
For quicker harvests, start with plants that are 2 to 3 years old if possible. If you can’t find plants at your local nursery, several mail-order nurseries carry them, or you can start new plants by taking cuttings from a neighbor’s.
Because they’re native to naturally boggy regions, cranberries do best in soils with low pH (between 4.0 and 5.0) and a lot of peat. Contrary to popular belief, they do not require saturated or flooded soils. Commercial cranberry growers flood their bogs at harvest time to make mechanical harvesting easier (the berries float), but cranberry plants resent having their roots completely saturated. Remember, cranberries are a bog plant, not an aquatic one.
To plant a cranberry bed, dig out an area approximately 10 inches deep, removing all the soil and setting it aside for a future project. Cranberry plants should be placed about 2 to 3 feet apart, so size the area according to the number of bushes you’d like to have.
Once the soil has been removed, fill the planting bed with 6 inches of peat moss. Add 1/2 cupful of acid-specific organic granular fertilizer, such as Holly-tone, for each plant you intend to locate in the bed. Mix the fertilizer into the peat moss. Slowly wet the peat by setting up a sprinkler and stirring up the peat every half hour or so. Peat takes a long time to absorb water, so don’t rush this step.
Once the bed has been fully moistened, rake it smooth and top the entire bed with four inches of very coarse sand. Plant your cranberry plants 2-3 feet apart and water them in well.
Keep the area weeded and water when necessary throughout the growing season. Do not keep the soil constantly saturated, but do keep the peat moist.
Do not add any additional fertilizer until the bed has been there for two or three years. Then make yearly additions of an acid-specific organic granular fertilizer and test your soil annually to ensure the optimum pH. If the pH needs to be lowered, pelletized sulfur will do the trick.
When To Expect Fruit
After a season or two, the runners will spread out and root, filling the bed with plants. Upright fruiting branches will be formed soon after. You can expect to see your first fruits when plants are between 3 and 4 years old.
Cranberries are best harvested late in the season but before the first frost. Lingonberries may produce two crops per season; one in the early summer and another in the fall. To determine the ripeness, crack open a berry and examine the seeds. If they’re brown, the cranberries are ready to harvest. The skin of the berries will also darken as the fruits ripen.
Cranberries are incredibly hardy and fully to semi-evergreen, depending on the variety. They’re self-pollinating, but they require bumblebees to shake the pollen loose.
Another bonus of growing this easy-care plant: Unlike other fruits, there’s no need to prune cranberry plants unless production drops off or the planting bed becomes too thick. If that happens, cut off some of the runners to encourage more upright fruiting branches.
Cranberry plants can live for decades, providing the grower with a lifetime of these deliciously tart fruits.