Summary of Frequently Asked Questions About Grape Growing

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, seed propagation.

Vegetative propagation is a method of propagating and raising vines by using part of the organs of a grape plant, mainly the stems. Its advantages are that the new plants show little variation, can maintain the varietal characteristics of the mother plant, and can be propagated multiple times in 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 raising is a modern propagation method, but it requires a relatively large investment and has higher requirements for facilities and technology.

Sexual propagation is a method of producing new plants from seeds, and it is the result of sexual hybridization and genetic recombination. The resulting new plants have great genetic variation and it is difficult to maintain 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 and time-consuming, and the breeding cycle is long, 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 shoots with the characteristics of the variety, cut in winter, as cutting material. Usually each cutting has 2 to 3 buds, and single-bud cuttings may be used for rare varieties. 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 convenient management into account, leaving small production paths and drainage and irrigation ditches, etc. Before the ground freezes in winter, the nursery site should be deep-plowed to about 50 cm, then superphosphate (50 kg per mu) mixed with organic fertilizer (pen manure, barnyard manure, compost, 3000 kg per mu) should be spread on the surface, followed by one rough raking, and after the ground thaws in spring, one fine raking. When soil moisture is poor, water thoroughly first, then form ridges and prepare beds for later use. In northern regions, ridge cutting for propagation is mostly used, as this helps with cold protection, heat preservation, and moisture retention. The nursery site should practice crop rotation and change crops to avoid continuous cropping. It is best not to use land previously planted with potatoes and solanaceous vegetables, so as to avoid damage from diseases and pests.

(2) Select good cuttings. Take the cuttings out of the storage trench and cut them to the required length. Single-bud cuttings are 5-10 cm long, and two-bud or three-bud cuttings are 10-20 cm long. Cuttings should be more than 0.5 cm thick, with internodes of uniform length, plump buds, pith not exceeding one third of the cutting diameter, bark yellow to reddish brown, and free of diseases and pests. When cutting, cut the upper end of the cutting flat at 1 cm from the bud, and cut the lower end diagonally close to 0.5 cm below the node, or even cut at the node, because nodes store more nutrients and are prone to sprouting and rooting. 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, chemical treatment is now often used to promote rooting. Usually, the base of bundled cuttings is dipped 1-2 cm in the chemical. But be sure not to let the chemical touch the terminal bud of the cutting. Commonly used chemicals 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 quick dipping, dipping the base of the cutting into the solution and immediately removing it; naphthaleneacetic acid 300-450 mg/kg may also be used for quick dipping. Experiments show that soaking one third of the cuttings in 0.2% monopotassium phosphate for 48 hours can also improve the survival rate of cutting propagation.

(4) Cutting time. For open-air cutting propagation, it is best to begin in early spring when the soil temperature reaches above 8-10°C.

(5) Cutting methods. Ridge cutting or bed cutting may be used.

① Ridge cutting. After deep plowing, fine raking, and leveling the nursery site, form 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 15-20 cm 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 may be inserted at an angle, with the terminal bud pointing upward and facing south, then cover with soil taken from the south side of the ditch, firm it with the foot, water thoroughly, and then cover with soil again, so that fine soil exceeds the terminal 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 raking, and leveling the nursery site, make beds 1-1.5 m wide in a north-south direction, generally 20-30 m long. Within the bed, dig ditches 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 terminal bud level with the ground, the bud eye facing upward and toward the sun. Cover the cuttings with fine soil 3-5 cm, then water thoroughly once. After the water seeps down, cultivate in time. If conditions permit, cover with film after cultivation to help preserve soil moisture and raise temperature, promoting rooting of the cuttings.

With ridge cutting, soil temperature rises quickly, buds sprout early, cultivation and weeding are convenient, ventilation and light transmission are good, and seedling growth is better than with bed cutting.

3. How is nutrient bag seedling raising carried out?

Nutrient bag seedling raising is a method in which, within protected facilities, cuttings are inserted into nutrient bags ahead of time so that the cuttings root and sprout early, and after the open-field frost has passed and the temperature is higher, they are then planted in the field. Nutrient bag seedling raising has a short seedling period, a high survival rate, and good seedling growth, and can significantly improve seedling raising efficiency.

The plastic bags used for this seedling raising method can be made from ordinary agricultural film. The plastic bags are about 10 cm in diameter and 18-20 cm high, with several small holes punched in the lower part or bottom of the bag to facilitate air movement and water seepage. The nutrient soil used for seedling raising can be prepared from fertile loam, manure, and aeration media (such as peat soil, fine cinder, river sand, etc.). The ratio of loam:manure:aeration medium is 1:0.5:1. Mix evenly and set aside.

When raising seedlings, 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 previously prepared seedling bed. The seedling 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 seedling bed (seedling raising can also be carried out in a plastic greenhouse). Generally, the temperature is kept 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 seedlings grow 5-6 leaves, they can be transplanted.