Latest Answers to Common Grape Growing Questions
1. How many methods are there for propagating grape vines?
There are usually two methods for propagating grape vines: one is asexual propagation, that is, vegetative propagation; the other is sexual propagation, that is, propagation by seed.
Vegetative propagation is a method of using part of the organs of the grape plant, mainly the stems, for propagation and for growing vines. Its advantages are that the new plants show little variation, can retain the variety characteristics of the mother plant, and can be propagated several times a year. Plants propagated by this method take shape early, grow quickly, and enter the fruiting stage early, so it is widely used in production. Asexual propagation methods include hardwood cuttings, green cuttings, layering, grafting, and tissue culture of shoot tips and stem segments, among which hardwood cuttings and grafting are used more often and are also relatively traditional methods. Tissue culture seedling production is a modern propagation method, with relatively large investment and higher requirements for facilities and technology.
Sexual propagation is a method of producing new plants from seeds, and is the result of sexual hybridization and genetic recombination. The new plants obtained have great genetic variation and it is difficult to retain the characteristics of the original variety, so this method is not used for propagating superior varieties. Traditional conventional grape breeding usually uses seed propagation, obtaining hybrid seeds through crossing, and then selecting new varieties with superior traits from a large number of seedlings. This method is often used for breeding new grape varieties, but it is labor-intensive, time-consuming, and has a long breeding cycle, so it is generally not suitable for vine propagation.
2. How are grape cuttings raised?
Grape cutting propagation is divided into hardwood cutting propagation and softwood cutting propagation. Hardwood cutting propagation is the method commonly used at present. It uses one-year-old branches cut in winter that have the characteristics of the variety as cutting material, usually with 2 to 3 buds per cutting, while rare varieties can use single-bud cuttings. Before hardwood cutting, the relevant preparatory work should be done well.
(1) Selection of the nursery site. The nursery site should preferably be sandy loam or loam with flat terrain, loose soil, close to a water source, and easy drainage and irrigation, while also taking into account convenient management, with small production paths and drainage and irrigation ditches left in place. Before the nursery site freezes in winter, it should be deep-plowed about 50 cm, then superphosphate (50 kg per mu) and organic fertilizer (pen manure, barnyard manure, compost, 3000 kg per mu) should be mixed and spread on the surface, followed by one rough harrowing, and after the soil thaws in spring, another fine harrowing. When soil moisture is poor, water should be thoroughly applied first, then ridges should be made and beds prepared for later use. In northern regions, ridge cutting is mostly used for propagation, as this helps with cold protection, heat preservation, and moisture retention. The nursery site should practice crop rotation and avoid continuous cropping; it is best not to use land previously planted with potatoes and solanaceous vegetables, so as to avoid pest and disease damage.
(2) Select good cuttings. Take the cuttings out of the storage trench, cut them to the required length, with single-bud cuttings 5-10 cm long and double-bud or 3-bud cuttings 10-20 cm long, cutting thickness above 0.5 cm, uniform internode length, plump buds, pith not exceeding one third of the cutting diameter, cutting bark yellow to reddish brown, and free of pests and diseases. When cutting, cut the upper end of the cutting flat about 1 cm from the bud, and cut the lower end diagonally about 0.5 cm just below the node, or even cut at the node, because the node stores more nutrients and is likely to sprout and root. After the cuttings are cut, tie them into bundles of 50 or 100 for root promotion or cutting.
(3) Soak the cuttings before planting. Put the cut and prepared cuttings in bundles into clean water and soak for 12-24 hours, until the cut surface is bright green and saturated with water. To improve the survival rate of cutting propagation, drug treatment is now often used to promote rooting. Usually, the base of the bundled cuttings is dipped 1-2 cm in the drug. But be sure not to let the top bud of the cutting contact the drug. Commonly used agents include: indoleacetic acid 40-50 mg/kg, sodium naphthaleneacetate 100 mg/kg, soaking for 12-24 hours; indolebutyric acid 100 mg/kg for 12 hours, or 200-300 mg/kg for rapid dipping, immersing the base of the cutting in the solution and then taking it out immediately; naphthaleneacetic acid 300-450 mg/kg can also be used for rapid dipping. Trials show that soaking one third of the branch in 0.2% monopotassium phosphate for 48 hours can also improve the survival rate of cutting propagation.
(4) Cutting time. Open-air cutting propagation is best started in early spring when the soil temperature reaches above 8-10°C.
(5) Cutting method. Ridge cutting or bed cutting may be used.
① Ridge cutting. After deep plowing, fine harrowing, and leveling the nursery site, make ridges. Make the ridges in an east-west direction, with a row spacing of about 50 cm, first dig a ditch 15-20 cm deep and wide, turn the ditch soil to the north to form a soil ridge 20 cm high, then insert the treated cuttings along the ditch wall at a plant spacing of 10-15 cm. If the cuttings are long, they can be inserted at an angle, with the top bud pointing upward and facing south, then take soil from the south side of the ditch to cover them, firm with the foot, water thoroughly, and then cover with soil again, so that the fine soil exceeds the top bud by 3-5 cm. If plastic film is used as cover or a small arched shed is built, it is even more helpful for the cuttings to root early.
② Bed cutting method. After deep plowing, fine harrowing, and leveling the nursery site, make beds 1-1.5 m wide in a north-south direction, generally 20-30 m long, dig ditches in the beds at a row spacing of 25-30 cm, with a ditch depth of about 10 cm, insert the cuttings into the ditches at a plant spacing of 10-15 cm, with the top bud level with the ground, the bud eye facing upward and toward the sun, cover the cuttings with fine soil 3-5 cm, and then water thoroughly once. After the water seeps down, cultivate in time; if conditions permit, cover with film after cultivation to help preserve moisture and raise temperature, and promote rooting of the cuttings.
With ridge cutting, soil temperature rises quickly, sprouting is early, cultivation and weeding are convenient, ventilation and light transmission are good, and vine growth is better than with bed cutting.
3. How is nutrient bag propagation carried out?
Nutrient bag propagation is the practice, within protective facilities, of cutting the cuttings into nutrient bags early so that the cuttings root and sprout ahead of time, and then planting them in the field after the open-field frost has passed and the temperature is higher. Nutrient bag propagation has a short seedling period, a high survival rate, and good vine growth, and can significantly improve propagation efficiency.
The plastic bags used for this propagation method can be made from ordinary agricultural film. The plastic bag is about 10 cm in diameter and 18-20 cm high, with several small holes made in the lower part or bottom of the bag to allow air and water to pass through. The nutrient soil used for propagation can be prepared from fertile loam, manure, and an aeration medium (such as peat soil, fine cinder, river sand, etc.), with the ratio of loam:manure:aeration medium being 1:0.5:1, mixed evenly for later use.
During propagation, put the nutrient soil and the treated cuttings into the bags; the nutrient soil should be compacted, leaving 1-2 cm of space at the top of the bag for watering. Arrange the filled nutrient bags closely in a pre-leveled seedling bed; the bed is 20-30 cm deep, with unlimited width and length. After the whole bed is filled with nutrient bags, water thoroughly immediately. To retain moisture and heat, a small plastic arched shed can be placed over the bed (propagation can also be carried out in a plastic greenhouse); generally keep the temperature at about 20°C and the humidity at 80%, not lower than 60%. When the cuttings grow 3-4 leaves, the arched shed can be removed, and when the new shoots of the vines grow 5-6 leaves, they can be transplanted.
4. How is nursery land management carried out?
Nursery land management mainly requires doing the following work well:
(1) Timely watering. In northern China, spring has little rain, and sandy soil with strong permeability should be watered frequently to maintain soil moisture; for heavy clay soil with strong water-holding capacity, the number of waterings can be appropriately reduced to avoid lowering soil temperature and affecting seedling growth. After entering May, water in time according to soil moisture; generally, water 5-7 times throughout the growing period.
(2) Topdressing. On the basis of applying sufficient base fertilizer (3000 kg of farmyard manure per mu), topdressing can be applied 2-3 times throughout the year. The first topdressing can be half a month after all the vines have sprouted, when the seedlings are about 20 cm high, applying nitrogen fertilizer together with watering, generally 15 kg of urea per mu. The second topdressing can be when the seedlings are 30-40 cm high, applying nitrogen, phosphorus, and potassium compound fertilizer, generally 15-20 kg per mu. In mid-to-late August, a phosphorus and potassium fertilizer can be applied, about 20 kg per mu. In addition, according to vine growth, foliar spraying can be carried out between several topdressings.
(3) Branch and vine management. When the seedlings are 30 cm high, set up trellises in time so that the branches and vines grow upright. After the new shoots are on the trellis, tie the vines and pinch the tips in time, and remove secondary shoots and tendrils. If the vines are robust, 1-2 secondary shoots can be retained at the base for rapid shaping.
(4) Pest and disease control. In early spring, in areas where underground pests or scarab beetles cause damage, poison bait or manual catching can be used. Before the rainy season arrives, spray once with 240-fold equal-strength Bordeaux mixture to prevent disease. After entering the rainy season, control should be carried out according to the type of disease, such as if white rot or black pox occurs, spray 200-fold equal-strength Bordeaux mixture or 800-fold Tuzet solution 2-3 times; for downy mildew, spray 500-600-fold metalaxyl or 400-fold Guoduofu solution 1-2 times. If leafhoppers cause damage, add 1500-fold Shenwei emulsifiable concentrate to the above agents.
5. How is the planting density of grapes determined?
The planting density of grapes depends on the training system used, and the training system is related to the variety, terrain, soil, and field operation methods. Concentrated grape production areas at home and abroad mostly use small trellis surface and high-density cultivation, planting 300-500 vines per mu. In our province, two main training systems are used in grape production, the hedge trellis and the small pergola. For hedge trellis cultivation, the plant and row spacing is generally 1×2 m; for small pergola cultivation, the plant spacing is generally 0.6-1 m, and the row spacing is 3-4 m.
6. How are planting ditches dug?
In order to cultivate grape plants with well-developed root systems and robust growth, before planting, planting ditches should be dug according to the row spacing. When digging grape planting ditches, they must be widened and deepened as much as possible, generally no less than 60 cm deep and wide. The ditching time is best in the autumn of the year before planting. When digging the ditches, place the topsoil and subsoil separately on both sides of the ditch, apply 8000-10000 kg of organic fertilizer and 50 kg of compound fertilizer per mu, mix evenly with the excavated soil, and backfill into the ditch, taking care to fill the subsoil first and the topsoil afterward, and finally irrigate to settle it, then rake it level for planting.
7. How should the vine preparation work be done before grape planting?
Before planting, first take the grape vines out of the storage ditch, and remove vines that are dry and withered or whose branches, buds, or root systems have become moldy and black. Tie the selected vines into bundles and soak them in clean water for a day and a night. Before planting, the vines should be properly pruned; branches and vines can generally retain 2-3 buds; lightly prune the root tips. This helps promote new roots and root system growth. To control short-whisker mites, scale insects, white rot, powdery mildew, anthracnose, and so on, the branch and vine parts of the bundled vines can be soaked in a disinfecting solution of 5 Baume lime sulfur mixture plus 0.1-0.3% sodium pentachlorophenate for 3-5 minutes, taken out and dried, then the roots can be dipped in mud slurry, and planting can proceed. During transport and before planting, the vines should be protected from sun and wind drying, and attention should be paid to moisture retention.