PROJECT RESULTS

Growing Grapes in Manitoba

Applicant: 

Thomas Menold
Carman, Manitoba  R0G 0J0  Canada

Table of Contents:

• Background and Objective
• Procedure and Project Activities
• Results and Discussion
• Conclusions

ARDI Project:

#98-235

Project Status:

Completed May, 2002

Background and Objective:

Grapes are nothing new to Manitoba. Native wild grapes can be found throughout the province. They are very hardy, able to survive the short growing season and severe winters. These two factors being the reason for the difficulty of consistently producing mature fruit and wood from cultured grapevines. The major limiting factor being the severe Manitoba winters. Most varieties are unable to withstand extremely cold winters without use of special cultural practices. New varieties are being developed that combine good quality with extreme cold hardiness.

Procedure and Project Activities:

Choosing Plant Stock

When choosing planting stock, it is best to deal directly with a reputable nursery, order early and negotiate a timely delivery for immediate planting. The ideal time to plant grapes is as soon as the soil can be worked usually early May.

There is a large difference in survival rate between self-rooted plants and own-rooted. It is recommended to purchase own-rooted plants as they have been raised outdoors the previous year and have developed buds. Self-rooted plants being cuttings started in a green house in February or March of the same year they are being sold. These tend to be more fragile with less developed root systems and very sensitive to the indoor-outdoor transition.

Most nurseries supply grafted plants, which have the disadvantage of not being able to be regrown from the roots if the grafted piece suffers from winterkill.

The grapevine is a long living woody perennial plant that cannot be relocated once established and, therefore, careful consideration must be given to a permanent planting site. The planting site should provide as much heat as possible. North-south rows allow better exposure of foliage to sunlight.

Grapes grow well in a wide variety of soils provided that drainage is satisfactory. Most garden soils contain adequate supply of organic matter, thereby eliminating the need of fertilization. More problems arise for the grape vine from ‘overfeeding’ than from ‘underfeeding.’

Rows should be spaced according to the size of equipment used in the vineyard such as tractor, cultivator, spreader (about 10 feet apart). This spacing of the rows will also provide sufficient air circulation (reducing the incidences of disease), sunlight exposure, and room to attend to individual plants. Before planting, trim roots and cut back vine to a single cane of two or three buds.

When using the training system, the appropriate plant spacing is 31 inches apart. The vine should be planted at the same depth as grown in the nursery, usually 8 inches deep.

The first four weeks of the newly planted grapevine are the most critical; a sufficient moisture supply is essential.

The use of grow tubes is not recommended. The tubes stimulate quick growth, but do not allow for proper maturing of wood necessary for winter survival. However, if grow tubes are to be used, monitor carefully and remove from plants in July, keeping in mind the risk of the plants getting scorched.

During the first two years of vine growth, all flower clusters should be removed since flowering and fruit production would drain most of the vine’s resources. By following this procedure, more resources are provided for the development of the root system and trunk of the vine.

It takes up to four years for a grape vine to produce at full capacity, at which time a vine may produce 5 - 10 kg of grapes, dependant on the variety.

The vines are pruned in early spring while the vine is still dormant. Some ‘bleeding’ of the vine may occur, however, this does no harm to the plant. By supporting the vines and restricting vegetative growth, maturity of wood and fruit is stimulated, yields are improved, exposure of foliage to sunlight is maximized, and disease resistance is increased (i.e. mildew).

The soil is worked well around each vine from early spring to mid summer. Later by allowing a cover crop to grow competition for water and other nutrients will also encourage maturing of the grape vine.

Plants with a leaf canopy higher off the ground will survive the first fall frost better, allowing for a longer maturing period. This system of training is conducive to laying vines down if necessary during the winter season. Varieties sensitive to the extreme cold need to have trunks with the flexibility to be laid down on the ground and covered throughout the winter. To provide this flexibility every two to four years as the need arises, a new shoot is trained from the bottom of the vine.

Severe winter temperatures (below –25°C) can set back or completely destroy a successful vine that has flourished for several years. One way to maintain reasonable production in marginal areas is to cover the vines during the winter season. There are several options available:

• Flax Shives: This is one of the more desirable winter coverings for vines as it is a very good insulator, sheds water from snow melt, repels rodents, easily removed in spring, may use a manure spreader with chute to cover vines, and may be worked into ground adding organic matter to soil.
• Snow: An excellent insulator, however, it is reliant on winter temperatures and moisture. There may not be enough snow available or the snow may melt before the freezing temperatures are done for the season, thereby exposing the plants to extreme temperatures.
• Straw: Insulates well, but attracts rodents, will soak up water from snow melt which then could freeze the vine if another frost were to occur.
• Soil: Another good insulator against severe temperatures, but it is harder to remove from vines making it more labor intensive, and may increase incidence of fungal disease.

• Weeds: Best practice is to weed manually with a hoe around each individual vine and cultivate between rows. This process not only gets rid of the competing weeds, but also aerates the soil and promotes heat absorption.  In Spring, RoundUp Transorb may also be used especially on hard to control perennials, being careful not to expose green foliage of grape vines to chemical.
• Mildew: Powdery mildew can be combated with the use of Nova. Downy mildew can be combated with the use of Dithane. These two chemicals can be tank mixed and, with label directions being followed, a good success rate can be achieved. It is recommended to use no more than three applications during the growing season. Preventative applications are applied pre- and post- bloom, especially on highly susceptible varieties.
• Deer: These herbivores favor the succulent grape leaves and new shoots. The most effective way to keep them from damaging the grape vines is fencing the vineyard.
• Cutworms: The tender young grape plants are most susceptible to cutworm damage. Cutworm dust (0.5% chlorpyrifos) may be incorporated on a regular basis as a preventative measure or if the vineyard is well monitored as soon as damage is noted.
• Wasps: Once the grape berries start to ripen, wasps will break open the skin of the grape and feed on the flesh. As a preventative and very effectual method, wasp traps can be hung in the vineyard. The wasp traps consist of household items that include a plastic bottle (no lid) that can hold at least 750 mL of liquid, a string to hang bottle from trellis system, and some WasPotion (approx. 175 mL/bottle).

WasPotion
2 tablespoons	sugar
250 mL	water
250 mL	vinegar
250 mL	fruit juice
Combine all ingredients and heat until sugar is completely dissolved.  Let cool and fill bottles to about a ¼ full each.  Tie the string around the neck of each bottle and hang into vineyard from the wires just as the grapes are starting to turn color.  One bottle will provide enought protection from wasps for approximately 20 grape plants.  Wasps are enticed into the bottles by the smell of the potion; they however are not able to get back out.

Results and Discussion:

More grapes are grown than any other fruit in the world. Of these, 90% are used to make wine. Grapes are also consumed fresh, in jams, jellies, juice, and baked delicacies. Grape seed oil is used in cosmetics, and as cooking oil is rated healthier than extra virgin olive oil.