Production Guide
Description
Considered a caneberry or bramble crop, red raspberry plants grow canes from crowns and root systems. The canes grow as biennials, and the crowns and roots are perennials. The berries themselves have a hollow center when harvested. This guide centers on red raspberry production; however, other raspberry berry colors are black, purple and yellow. Purple raspberries — produced by crossing red and black raspberries — are rarely raised by Missouri commercial operations. Red raspberries that have a certain mutation produce yellow berries.
As a crop that prefers cool weather — including summer temperatures that don’t reach 85°F — raspberries may experience some challenges, such as stunting, small fruit size and crumbly fruit, when raised in Missouri. Berry flavor also isn’t as good if temperatures are warm when the fruit matures. The warm temperatures can inhibit photosynthesis in raspberry plants. Some varieties may tolerate warm summer weather better than others.
Site Selection
A raspberry planting site should have good soil drainage. Raised beds may work well in areas that otherwise don’t drain well. However, planting in raised beds may mean that soil temperatures reach higher levels. Sites that provide afternoon shade or a north-facing orientation on a slope may help with temperature control.
Raspberries prefer deep, fertile soil that lacks a hardpan and has a high level of humus. If organic matter levels are low, then growers may apply and incorporate 10 tons to 20 tons of organic matter per acre. Time the organic matter application to occur roughly six months to 18 months in advance of planting. Growing a cover crop may also add organic matter. The pH level should range from 6.0 to 6.5.
Air drainage is another site selection variable. Elevation and slope allow cool air and humid air to drain from the growing location. During the spring and fall, poor air drainage could result in cool air causing frost damage. If humid air doesn’t drain from a site, then high humidity levels could trigger disease development. A desirable site would have at least a 2 percent to 3 percent slope to facilitate air drainage.
Crop rotation is important. Avoid sites that recently have raised crops susceptible to Verticillium wilt. Examples include strawberries, brambles, tomatoes, peppers and potatoes. Selected sites should also lack proximity to wild brambles, which can serve as a source of insect pests and diseases. Eradicate all wild brambles growing as close as 600 feet to the planned raspberry planting site. Then, conduct routine checks to ensure that wild brambles haven’t re-emerged. Planting sites should have persistent and perennial weeds removed. To eradicate weeds, growers may choose to implement practices such as planting cover crops, using solarization, fumigating the site, applying herbicides or tilling the soil.
Fertility
From a fertility perspective, raspberry plants do well with soil that has 50 pounds to 100 pounds of phosphorus, 250 pounds to 300 pounds of potassium and 150 pounds to 200 pounds of magnesium — these are per-acre amounts. Producers can compute fertilizer needs based on soil test results. Often, in the fall before planting, producers apply potassium, phosphorus and magnesium as necessary. Modify soil pH if needed with lime or sulfur before planting, as directed by a soil test.
With respect to nitrogen, a good practice is to apply roughly 25 pounds per acre during the planting year. During the second year, apply roughly 40 pounds of nitrogen per acre, and in later years, an estimated 50 pounds per acre are required annually.
After establishing a raspberry planting, taking leaf samples and soil samples can help producers identify supplemental nutrient needs.
Variety Selection
Raspberry varieties are generally grouped into two categories: primocane-fruiting cultivars and floricane-fruiting cultivars. Floricane-fruiting varieties — also known as summer-fruiting raspberries — produce new canes each season called primocanes. In the second season, those canes are known as floricanes, and they flower and yield fruit in the summer. Primocane-fruiting cultivars are an alternative. They yield berries in the fall on first-year primocanes, and they produce a second crop on the same canes when they become floricanes in the second year of growth. Everbearing and fall-bearing are other terms used to describe primocane-fruiting raspberries.
Producers selecting raspberry cultivars will want to consider a given cultivar’s yield potential, berry characteristics, chilling requirement, bloom time, harvest time and fruit shelf life. Chilling refers to logging roughly 800 hours to 1,800 hours at a temperature ranging from 37°F to 50°F. Consistently cool temperatures tend to best help with accumulating chilling hours. Additionally, try to choose varieties that tend to resist Phytophthora root rot and other diseases. Because of pest pressure, varieties that produce fall fruit may not perform as well.
The following table lists red raspberry varieties to consider for Missouri production.
Red Raspberry Varieties for Missouri
| Variety Name | Variety Type |
| Caroline | Primocane |
| Heritage | Primocane |
| Josephine | Primocane |
| Polana | Primocane |
| Autumn Bliss | Primocane |
| Prelude | Floricane |
| Autumn Britten | Primocane |
| Canby | Floricane |
| Reveille | Floricane |
| Titan | Primocane |
| Lauren | Floricane |
| Nova | Floricane |
| Himbo Top | Primocane |
| Polka | Primocane |
Planting
At planting, growers can choose to plant dormant rooted cuttings or tissue-cultured plants. Transplanting from patch to patch isn’t recommended because the transplants may introduce viruses or diseases to the new planting site. Planting timing varies according to the planting stock used. With dormant raspberries, plan an early spring planting date. With tissue-cultured plugs, plant after frost risk has passed, and harden off the plugs before planting by periodically moving them into the sun.
When planting tissue-cultured plugs, ensure that the top of soil level around the plug is about 0.75 inches deeper than the planting site’s soil surface. Bare rootstock and mature tissue-cultured plugs should be planted as deep as the nursery had planted them, and cut stems to 5 inches. Rows typically are spaced at every 8 feet to 12 feet, and within a row, 2- to 3-foot spacing works well. To prevent sunscald on fruit and encourage high-quality fruit production, consider orienting rows from north to south. If wind poses a risk, then add a windbreak.
After planting, growers may apply 3 inches of weed seed-free organic mulch around plants. Options include straw and bark chips. Mulch may keep soil temperatures cool and minimize weed pressure and erosion, but mulch in an established raspberry patch may also enhance the likelihood of root rot and disease pressure. The mulch could also serve as a rodent habitat.
Water Management
Raspberries are a shallow-rooted crop. This characteristic makes irrigation essential. Raspberry plants often require 1 inch of water every seven to 10 days. Water needs increase during hot, windy conditions.
Drip irrigation systems work well as they efficiently use water and minimize contact between irrigation water and raspberry plants. With a drip irrigation system, producers also have an alternate method to supply fertilizer to plants.
Overhead irrigation systems are another option, though using them may increase disease risk as an overhead water application can expose leaves, flowers and fruit to moisture. Not only do the overhead systems have the potential to apply irrigation water for plants to absorb, but they also may protect plants from frost and keep them cool when temperatures are warm during the harvest season. If using overhead irrigation systems for their evaporative cooling benefit, then the moisture on plants and fruit should have an opportunity to dry before dusk.
Cultural Management
Without adequate pollination, raspberries may develop a crumbly-like appearance because too few druplets form. To facilitate pollination, producers may provide two strong beehives per acre. Operations with relatively large raspberry patches may particularly require an investment in beehives to support good pollination.
Raspberry canes require pruning, but the specific pruning needs depend on the cultivar. Summer-bearing raspberry plants produce canes that live for two years. After floricanes yield flowers and fruit, they die. When the plant is in dormancy, prune those dead canes by hand. Also, remove dead or diseased canes from plants. Other pruning needs for floricane-fruiting varieties includes thinning canes. Per square foot, choose to keep three or four canes. Also, spring pruning for floricane-fruiting raspberries will require cutting back canes to a height not taller than 4 feet.
Pruning differs for primocane-fruiting plants. In the winter following the berry harvest, operators often mow the canes. The canes could yield a limited number of berries in the following summer. However, mowing canes can reduce the labor effort needed for pruning and serve as a good insect and disease management strategy. When new canes reach a 1-foot height, growers can mow canes again in an effort to prevent the primocane-fruiting plants from bearing fruit too early in the year.
Depending on the producer’s preference, a trellis system can be used for raspberry production. Using a trellis can encourage air to circulate. Post-and-wire systems structured as an I-trellis, two-wire trellis or V-trellis are options. The I-trellis and two-wire trellis work well for trailing cultivars. With an I-trellis, tie canes to a single wire positioned 3 feet or 4 feet from the soil surface. A two-wire trellis enables growers to weave floricanes through the wires or tie the canes to resemble a fan. The wires are placed 3 feet and 5 feet above the soil surface. With a V-trellis configuration, posts form a “V” shape, and wires run from one set of “V” posts to another. Growers tie floricanes to the wires to create a “V.” As primocanes emerge, they grow upward in the middle of the “V.” If they don’t grow in a trellis, then red raspberry plants develop a hedgerow.
A high tunnel refers to a plastic-covered hoop house. Raising raspberries in a high tunnel or greenhouse may aid growers in producing berries that are larger and firmer, and productivity may improve. Growing raspberries in a covered high tunnel may also reduce pest pressure, and at the plant level, high tunnels may provide improved temperature stability. Suitable sites for constructing a high tunnel are those that are level and offer good drainage. Ensure that a high tunnel has enough space between it and other objects that could block light or inhibit air flow. Good ventilation can manage relative humidity levels to prevent disease; powdery mildew and rust are particular challenges in environments with high relative humidity levels. To ventilate high tunnels, producers may open the sides or the end doors. Adding roof vents or vents in the end walls may also facilitate air exchange. Taller high tunnels may offer better temperature control and air circulation. A moveable high tunnel serves as another option for raspberry producers.
Growers may choose from several approaches when planting raspberries in a high tunnel. Planting in the soil under a tunnel serves as one option. An alternative involves establishing the raspberry plants in pots or bags, which can move in and out of the high tunnel as needed. Raspberries can also occupy one production plot for a movable high tunnel, as the protection afforded by the tunnel is needed primarily during the growing season. Given that the plastic-covered structures prevent rainfall from reaching plants, an irrigation system and access to irrigation water are critical. With a drip system, producers can also supply nutrients via fertigation as necessary. If raising raspberries that bloom early, then adding a beehive can encourage better pollination. Periodically, operators may need to remove the plastic from a high tunnel structure to encourage soil salts to leach from the site soil with rainwater. Also, as mentioned earlier, raspberry plants do not tolerate hot temperatures as well as other fruit crops. Growers raising raspberries in a high tunnel may use shade cloth to keep temperatures cooler and minimize sun-related fruit damage.
Weed Control
Weed pressure is particularly important to control as raspberry plants establish themselves; the first two years are critical. Ideally, 2 feet on both sides of a row will lack weeds. Growing sod between rows can help to control weeds. To manage weeds, producers may use a combination of cultivation, mulching and herbicide applications.
If using cultivation to control weeds, then monitor the cultivation equipment to ensure that it doesn’t damage plants. It should stay at least 2 inches from canes and disturb no more than the top 2 inches of soil. The mulch may control annual weeds. Organic options may have soil fertility benefits, but plastic mulch is another option, though it can cause soil temperatures to increase and may make it more challenging for primocanes to grow. To manage weeds by spraying herbicides, a good practice is to choose herbicides meant to address specific weeds rather than use a broad-spectrum systemic alternative.
Insects and Diseases
Insect pests may target fruit or the raspberry plants themselves. Pests known to affect raspberries include mites, cane borers, aphids, Japanese beetles, spotted wing drosophila, stink bugs, green June beetles and raspberry crown borer. Nematodes present another risk as they could introduce viruses. The spotted wing drosophila — a type of fruit fly — can present significant challenges, particularly if raising red raspberries that bear fruit in the fall. In fruit, including undamaged berries, the female spotted wing drosophila lay eggs. After the eggs hatch, the berries experience rapid deterioration.
Pest management practices include identifying a suitable site, rotating crops, choosing suitable varieties, applying pesticides and selecting plants that lack disease. In some cases, operators may choose to remove pests by hand; this approach may work in small plantings for stink bugs, Japanese beetles and green June beetles. Planting sites that have nematodes may require fumigation, and regularly spraying for the spotted wing drosophila is necessary. For small acres, another option to prevent damage from spotted wing drosophila is to place row covers over rows at harvest time. If growing raspberries in a high tunnel, then covering the sides and ends with a mesh screen may prevent pest damage. Beneficial insects such as parasitic wasps and ladybugs can target some harmful insects.
Several types of diseases may target raspberry plantings. They include anthracnose, cane blight, spur blight, crown gall, Phytophthora root rot, crown rot, fruit rot, mosaic virus and Verticillium wilt. To minimize disease incidence, choose raspberry varieties that tend to resist problematic diseases, always plant virus-tested nursery plants, and apply fungicides as necessary. Selecting a suitable site can also help to limit disease risk. Regularly harvesting berries as they ripen is a tool to reduce fruit rot. If air can circulate well, then fruit rot may also be less likely to occur.
Harvest and Storage
Because raspberry crowns are perennials, the crop requires an establishment period before it reaches full production. In the third year, summer-fruiting varieties will yield the first significant crop, and for everbearing varieties, plants begin producing significantly in the second year. Harvest relies on hand labor if marketing raspberries as a fresh product. Berries intended for processing may be mechanically harvested. Missouri-produced raspberries, however, are most frequently consumed fresh. As an alternative to hiring workers to pick berries, producers may operate a pick-your-own raspberry patch.
At harvest, berries should detach easily, and they should feel firm. In terms of color, look for bright red berries. At that stage, the berries are ripe and firm, and they’re less likely to be “leaky.” Berries that are dark red are softer and would require careful handling and immediate marketing.
Raspberries being marketed should lack insect damage and rot. Pickers should also remove berries infected by disease or damaged by pests, and the damaged berries should be destroyed somewhere other than the growing location. If not picked in a timely manner, then the berries may rot and draw pests. When the weather is hot and rainy, growers may need to increase the raspberry harvest frequency.
Harvest berries in the morning, after dew has dried but before air temperatures warm. At that time, berries are tugid and firm, and easier to handle. Because raspberries are delicate, pickers should place harvested berries in containers in which the berries will be marketed. Place no more than two or three layers of berries in a container, or the weight of the berries may crush fruit at the bottom of the containers. Plastic clamshells that protect the berries allow for stacking.
Quickly after harvest, cool the picked berries to minimize quality deterioration. A forced-air cooling system tends to work well. The storage area should have a temperature that ranges from 30°F to 35°F. Relative humidity levels should range from 90 percent to 95 percent. During berry transportation, cool temperatures are also important, and those handling the berries should avoid damaging the fruit.
Sources
Bordelon, Bruce. 2001. Raspberries. Purdue University Cooperative Extension Service. West Lafayette, IN 47907.
Demchak, Kathy, Jayson K. Harper and Lynn Kime. 2017. Red Raspberry Production. Penn State Extension. Building University Park, PA 16802.
Eaton, Touria and Patrick Byers. 2017. Red and Yellow Raspberry Cultivars Recommended for Production in Missouri. Lincoln University Cooperative Extension. Jefferson City, MO 65101.
Fernandez, Gina, Frank Louws, Jim Ballington and Barclay Poling. 2014. Growing Raspberries in North Carolina. NC State Extension. Raleigh, NC 27695.
Fiser, Spencer, Luke Freeman, Heather Friedrich, M. Elena Garcia, Donn Johnson, Leah Malvar, Jennie Popp, H. German Rodriguez, Curt Rom, Julia Stover and Christopher Vincent. Pruning Raspberries, Blackberries and Gooseberries. University of Arkansas. Fayetteville, AR 72701.
Kaiser, Cheryl and Matt Ernst. 2016. Raspberries. University of Kentucky. Lexington, KY 40506.
Koester, Kurt and Marvin Pitts. 2003. Greenhouse Raspberry Production Guide. Cornell University. Ithaca, NY 14850.
Pritts, Marvin, Laura McDermott, Kathy Demchak, Eric Hanson, Courtney Weber, AJ Both, Greg Loeb and Cathy Heidenreich. 2017. High Tunnel Raspberries and Blackberries. TunnelBerries.
Warmund, Michele. 2016. Fruit Production. University of Missouri Extension. Columbia, MO 65201.