Goji Berry Culture
Goji is also known by a number of other names including goji berry, wolfberry, boxthorn, and matrimony vine. In China, where most of the world’s commercial Goji berry production is found, most plants with high quality fruit are of Lycium barbarum L. var. barbarum, though some Lycium chinense Mill. var. chinense is also grown. World-wide, other closely-related species or subspecies may also be harvested and are known by the same or similar common names, though the fruit quality and productivity is likely to be lower. Plants can be found growing in nearly all U.S. states and Canadian provinces.
There have been various attempts at growing Goji undertaken throughout the U.S. and Canada. Probably the largest-scale attempts in the East are taking place in Ontario, where 4 acres are under cultivation. As many as 18 acres were under cultivation at one point in California.
The Goji plant is a slightly thorny deciduous woody shrub, typically 3 to 6 feet tall when cultivated and pruned, though plants can reach 12 feet tall in their natural state. Goji is a member of the solanaceous (tomato or nightshade) plant family, so its cultural and nutritional needs are similar.
Current Growing Recommendations
Soil Type and Site Selection
Goji plants are adaptable and grow in a range of soil types, with a preferred pH of 6.5 to 7.0. Goji won’t tolerate salinity well (though information can be found indicating that some of its relatives will) and prefers high fertility soils. The best growth is made in relatively light soils that are well-drained such as sandy loams or loams and in areas with plenty of sunshine. Plants can be grown in USDA Hardiness Zones 2 to 7.
Breeding efforts in North American have been undertaken only within about the last decade. Currently, only two named varieties, ‘Crimson Star’ and ‘Phoenix Tears,’ are available to all growers. A Canadian company in Saskatchewan, Wolfberry Agrodevco, offers plants of ‘Sask Wolfberry’ to cooperating growers only.
Otherwise, plants may be grown from open-pollinated seed, but plant growth habit and productivity may be variable. Growers who intend to buy plants may wish to ask whether the plants were vegetatively propagated from superior clones or were grown from seed. Some nurseries that sell Goji plants are listed on the Cornell berry supplier web site under the “Miscellaneous” category.
Plants grown from seed are similar in appearance to tomato seedlings at first. Seedlings and young plants are likely to be variable in appearance, and can be grown in a nursery until the following year, when they can be transplanted to the field. Dormant nursery stock should be planted in spring once danger of frost is past.
Mulching after planting with an organic mulch can keep down weeds, moderate root temperatures, and promote establishment. Irrigation is highly recommended especially during the establishment year, as the root system is fine and can easily dry out, and the fruit are prone to blossom end rot under conditions of low or uneven moisture. However, overwatering should be avoided. Plants should be spaced 3 to 5 feet apart within the row and at least 6 to 8 feet between rows, though wider between-row spacing may be needed to accommodate equipment.
Time to maturity and yield
Plants will begin fruiting two years after seeding, or the year after planting if one-year-old transplants are used. Full yields will be reached four to five years from seeding. Maximum yields in China are reported to be about 7000 lb/acre.
No work has been conducted on fertility requirements in the region; however, a good starting point would be to amend the field as for tomatoes. Nitrogen at 75 to 90 pounds per acre per year is recommended for a mature planting, split into three applications applied at budbreak, at flowering, and then as fruit begin to ripen. Plants are sensitive to high salt levels; compost can be used to provide nutrients as long as salt levels are not excessive.
Fruit are borne on the current year’s wood, mainly from that which is grown in the spring and fall. The goals of pruning are to limit plant height, improve ease of harvest, encourage light penetration into the plant, improve foliage drying, and encourage formation of lateral branches to maximize fruit production. Canes that are untipped will continue to grow and produce few lateral branches while canes that are headed back will produce more laterals and higher yields.
Little research has been conducted to determine the best pruning methods for our region. However, in other production areas, plants usually are limited to one single main stem. Pruning is done during the dormant season to remove spindly canes, remove dead and damaged wood, improve plant shape, and shorten laterals. During the summer, pruning is done to head back growth, encourage lateral formation, and remove new shoots. One of the most important goals of pruning is to produce an open canopy structure that allows plenty of sunlight infiltration.
Plants first bloom in late spring to early summer, and fruit will begin to ripen in mid-summer. Currently harvesting is completed by hand, as the berries leak juice and turn black if they are bruised, or squashed. Berries are currently sold mainly as a dried product, but they can also be sold and eaten fresh, or turned into juice. Labor requirements are substantial.
Pests and Pest Control
In Ontario, pests of goji included potato leafhopper, Japanese beetle, thrips, aphids and spider mites. Spotted wing drosophila adults have been present in production fields though extent of fruit infestation by larvae was not determined. Diseases included anthracnose, early blight, and powdery mildew. Blossom end rot was an issue as well if moisture levels were uneven. Aphids and a gall mite have been problematic in other countries, and birds are reported to have an affinity for the fruit. Goji is included in Crop Group 8-10 (Fruiting Vegetables) and subgroup 8-10A (Tomato Subgroup). Thus Goji appears on products that are labeled for this entire group or subgroup.