WATERING
Grapevines are beautiful plants with their lush leaves and jewel-like fruit. Fortunately they are easy to grow and thrive in mild climates like the Mediterranean climates. They tolerate poor soil and are self-pollinating, but they need regular watering and a good amount of sunlight. A mature vine requires about 8 to 10 gallons of water on a hot day, which is 30.3 to 37.9 liters of water per day.
If you are using bare-root plants, it is possible that the vines can experience something known as transplant shock, to minimize this shock, newly planted grapevines need immediate watering. In the absence of rainfall, vines need to be watered regularly throughout the entire season. Soil should be wet about 6 to 10 inches beneath the surface, but if you overwater then it might cause root rot. If the plants are established, they can tolerate some drought and even they would require almost regular watering. The plant might not bear fruit during drought conditions. You can cut down on watering slightly once the vines bear fruit to encourage the ripening of fruit.
How much water you need depends on the growing conditions and also the type and characteristics of the soil. Water usually collects in heavy clay soils and tends to leech out quickly from sandy soils. Heavy soils usually show benefits when watered infrequently by they need deeper watering, but grapevines don’t grow the best in clay vines, these soils need to be amended. Sandy soils benefit from frequent shallower watering. During conditions like windy and dry weather, vines need more water. There are various watering strategies that can be used. You could use soaker hoses, drip systems or sprinklers. Soaker hoses conserve moisture by delivering water directly to the roots of the grapevine. They also reduce the risk of fungal diseases by keeping the leaves dry. Some growers, in order to trap water, make a small depression in the soil.
How to water a grapevine:
Young grapes need constant watering, there is some debate as to whether the more mature grapevines require irrigation at all, but some irrigation can definitely help plant health and fruit production. Following steps will help you to properly water your own vine:-
- You can either have an underground drip irrigation system installed or set up a perforated hose along with the grapevines at the base. To avoid excess moisture, fungal diseases and water waste, choose the method of drip irrigation. If you want, the easiest way is to water using a hose by hand.
- Water the vines during their first season of growth regularly, keep the soil moist while the plants are starting to grow from cuttings. Once the vines are more mature or a little larger, you can water once every two weeks or three. Adjust water amounts based on the weather conditions and temperature. Make sure that you get the water to the deepest grape roots. You will need to water vines more often in dry summery weather, especially in the warmer areas.
- During very dry weather, when the vines are producing fruit, water mature grapevines more often. They will not need any additional watering during the rest of the year. If you notice vigorous vine growth but slow development of fruit, reduce irrigation until the fruit matures and vines grow fewer shoots.
How to schedule vineyard irrigation?
In many vine-growing regions, in order for the vines to thrive, it is necessary to irrigate them or to fill in gaps due to lack of water during the summer months when there is intensive vine growth. Water is a limited source, hence a lot of grape growers try to provide enough water for vines but also minimize water usage at the same time. Good water management is very crucial.
Accurate field data which consists of information from vineyard soil moisture sensors, pressure chambers, and on-site weather stations are required for perfect irrigation management,
When to start irrigating vineyard?
The following are some of the ways to determine the start and timing of irrigation:
- Monitoring soil: the soil is monitored at different levels of root zones of the grapevine.you can start irrigating at the value of soil moisture level, this can ensure the need for water is reached. There are various types of soil moisture sensors available to help you out, they can measure soil on different depths.
- Measure vine status: you can measure the vine water status, at about 10 bars, water deficit is experienced by the vines. A pressure chamber can be used to monitor the grapevine water status.
How much water to apply to each vine?
Requirements of vine water depend on a lot of different factors like grapevine variety, root depth, and grapevine growth stages and also climate and vineyard soil characteristics. You can schedule irrigation to be daily, weekly or 10-days for example. In order to gain a perfect understanding of how to irrigate vines, you need to understand the various growth stages. The main stages of growth are:
- Budbreak – flowering: during this stage, the requirement for water is moderate, about 9%. This is the most crucial stage for the current and following season as it is the most important stage for root growth.
- Flowering – fruit set: during this stage, the water consumption is about 6% of the season’s total consumption. Water stress may lead to poor flower or cluster development, it is the most sensitive period.
- Fruit set – veraison: this long period needs about 35% of the annual requirements of water, if the canopy is not developed sufficiently, it may affect the quality of vine due to lack of photosynthesis.
- Veraison – harvest: this stage needs about 36% of water as per annual requirements. During this period, the main goal of irrigation is to maintain a healthy canopy and avoid vine stress.
- Harvest – leaf fall: during this stage the consumption of water is only about 14%. It is still very crucial to maintain a healthy canopy and ensure sufficient build-up of reserves of carbohydrates in the wood of the vines for the next season before slipping into a dormant state.
Signs of overwatering:
To determine if you are overwatering your plants, you need to look for the following signs:
- Wilting but wet soil: if the plant looks wilted but has wet soil, you may have overwatered, to prevent this, only water when your soil is dry to touch.
- Leaves are brown: if you notice the leaves are brown and wilt, you might have overwatered, if this happens it’s difficult to tell if the plant is suffering due to poor health or improper level of water. The first step is to check your soil near the plant base, if the soil feels dry, it may need water.
- Edema: if a plant absorbs water in excess of its needs, the plant’s cells expand and stress, they are filled to the point of rupturing. Any blisters or lesions on the plant are some signs of edema. After a while these lesions turn to white or dark scar tissue.
- Falling yellow leaves: if the leaves turn yellow and new growth also starts falling from your plants, it’s a sign you are overwatering, you need to remember to only water when your soil is dry.
- Root rot: roots can also indicate overwatering, when soil is dense with a lot of water, the roots may not be able to breathe, they will drown and begin to rot. Plant root rot is a fungal disease and will eventually cause the plant to wilt.
TRAINING and PRUNING
Pruning is mainly done in early winter. Sometimes pruning can weaken the plant by causing the vine to bleed sap.
Cane pruning or guyot, is used in regions like Burgundy, Oregon and Sonoma, its used commonly in cooler climate growing areas. In cane pruning, all the vines prior growth is manually cut back and a single cane is correctly selected which will actually be responsible for the production next season. Cane pruning takes a lot of skill and it is difficult to do well. By this method, the vine is less vulnerable to frost. Many of the world’s prestigious wine-growing areas adopt cane pruning.
In warmer climate growing regions, spur pruning or cordon, is more common. In regions like Spain, Washington and California, spur pruning is done. Different styles of spur pruning methods are used for different types of grapes. The stub of a can that contains 1 to 3 buds are called spurs. They are generally easier to prune and are ideal for drought-prone areas. Spur pruning is a more traditional method that produces outstanding old vine wines.
Training of new shoots is usually done in spring and summer. Well trained grapevines have a pretty strong framework, you can select from a range of training methods for your grapevines, once fully trained the trunk must be left alone. Training methods are adopted based on climate and terroir. Before learning about the training methods, you need to know about the different types of vines. The four types of vines are:
- High vines: tall vine trunks increase airflow, sun exposure and lift the grapes high above the ground. This is used in cooler climates.
- Low vines: commonly used in hotter climates, reduce vine’s sun exposure levels and moderates variation in temperature.
- Widely spaced vines: spacing the vines from each other ensures greater nutrient access from the soil, it is common in very dry regions.
- Closely spaced vines: this limits the vigor of each vine, also limits production and quality improvements.
Steps to train a standard vine:
- Use a stout bamboo cane to train the main stem. The stem will be trained up the cane, remove any excess stems which are likely to appear at the base.
- For the first one or two years, allow side branches to develop on the main stem.
- Remove all the side branches from the middle and top of the stem, in the third winter. Leave only the top branches, allow 5 to 6 branches to develop at the top of the stem.
- All the side branches must be pruned to five leaves, do not allow them to get any longer.
- Any off-shoots developing from the side branches to one leaf should be pinched back.
- In the first cropping year, all one branch of grapes to develop, removing any other ones that begin to develop.
- Allow one bunch of grapes to develop on each side of the branch in the coming years.
- Prune the side branches back to two buds in the winter.
Grapevines need to be properly trained and pruned during the first three years of the growing season. Annual pruning is needed, once they start fruit production to maintain the balance between the fruit production and vegetative growth. If grapevines will produce excess fruit in one year, they will not produce a good crop the subsequent year and could also suffer winter damage.
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