How Often Should You Water a Grape Vine?

When you bite the fleshy, juicy pulp of grapes, it’s easy to assume that they need a lot of water. However, grape vines are very efficient users of water. Not only should you know how much water they need, but how often to water them if you want healthy fruits. 

You should water a grapevine with an inch (2.5 cm) of water once a week. Young grapes need consistently moist soil, so you may need to water the area twice weekly. Older vines need less frequent watering because of their deep roots. If the soil is fast-draining or the area is hot, water more frequently.

The amount of water needed and how often you should water grapes depends on the age of the vine, the grape variety, soil conditions, and the season. I’ll discuss these factors as well as the risks of underwatering and overwatering grape vines. 

How to Water Grape Vines

Grape vines are hardy and drought-resistant, but they still need water to thrive. Underwatering can cause the leaves and fruits to fall prematurely, whereas overwatering will result in root rot and grape diseases. Therefore, you’ll need to find a balance when watering grape vines. 

You also have to consider the age of the vine. Like other plants, grape vines have different watering needs, depending on the stage of growth.

Younger plants need water more because they have a shallow root system while older, more established grape vines have more access to water due to their deeper root system. 

Watering Young Vines (First Two Years)

Provide an Inch (2.5 cm) of Water Weekly

Water young grape vines with an inch (2.5 cm) of water weekly. Saturate the root zone up to 6 inches (15 cm) deep to ensure the young, shallow roots get consistent moisture.

You may need to divide 0.6 gallons (2.3 L) of water per square foot (0.09 sqm) into two watering sessions weekly if you have fast-draining soil.

Reduce Frequency With Root Growth

Reduce the watering frequency as the roots grow deeper and wider. You can still use 1 inch of water but consider the size of the roots.

At approximately 1-2 years old, most roots expand within a 2-foot (0.6 m) diameter, resulting in a 4-square-foot (0.38 sqm) coverage. That means you must water the root zone with about 2.5 gal (9 L) of water weekly.

Avoid Transplant Shock

Newly transplanted grape vines require immediate and regular watering to ensure they don’t die from transplant shock. This is especially important for grape vines initially grown in pots. 

Drench the soil 6-10 inches (15-25 cm) deep for newly planted grape vines. If you water your grapes any deeper, the roots may start to rot. 

Watering Older Vines

Once the trunk is established, the grapevine no longer needs to be watered as often as it did in the first few years. However, you should maintain the same watering patterns if your grapevine is growing in sandy soil or if there is a prolonged drought. 

Water Less Often

Older vines can go for extended periods without water unless the soil is fast-draining. If your region doesn’t have enough rainfall, you should drench the root zones with water up to 12 inches (30 cm) deep once a week. That’s usually about 5.4 gallons (20 l) of water per vine.

Monitor Temperature & Soil Drainage

Adjust the watering volume and frequency depending on the temperature and soil drainage. If you live in arid areas like Central California, you may need to use approximately 8-10 gallons (30-38 L) per vine per week.

Water grape vines less frequently in the fall as the vines need to harden in preparation for winter.

Avoid Watering Leaves

Avoid watering the leaves because it will encourage grape diseases, like downy mildew and powdery mildew.

Table Grapes vs. Wine Grapes

When it comes to watering grapes, you also have to consider the type of grapes. Table grapes usually require water regularly until you start harvesting them. Wine grapes, on the other hand, produce the best flavor when you reduce the water by half in the final stages of ripening. 

Start reducing the watering from once a week to once every 10-14 days as you get closer to harvesting wine grapes. Most winemakers use this method to increase the concentration of flavors before they harvest the grapes.  

Here is a table summarizing the key differences between table and wine grapes:

Table GrapesWine Grapes
Thin skinThicker skin increases the flavor
Larger fruitsSmaller fruits
Vines have lots of fruitsFewer fruits on the vine
No seeds or very small seeds Large seeds add flavor to the fruit
Higher yield Smaller number but higher quality grapes
Brix (a measure of sweetness) of 17 – 19Brix of 24 – 26

Efficient Watering Methods

Knowing how much water and how often to water your grape vines is not enough. You also need to know how best to water the vines. You should opt for methods that will get water to the root zones without getting the foliage wet

Let’s explore your options:

Drip Irrigation

Drip irrigation is one of the best ways to water your grape vines. The water gets right into the soil and feeds the roots without getting the foliage wet. However, there is the risk of overwatering or underwatering the grapes if you don’t keep track of the amount of water you are giving the vines.

To avoid this scenario:

  1. Start by testing the drip lines on a bare patch.
  2. Allow the water to run through the drip lines for five minutes. 
  3. Turn off the water and wait for some time for the soil to take in the water. 
  4. Check the soil to identify the depth of wet soil.

For example, if 5 minutes of drip irrigation moistens the soil 2 inches (5 cm) deep, then you can easily tell that 10 minutes of watering will saturate the soil 4 inches (10 cm) deep.

Based on the values above, younger vines will need about 15 minutes of drip irrigation. When watering established vines, you need to run the drip lines for at least 30 minutes to properly soak the root zone, which usually runs 2-3 feet (0.6-0.9 m) in diameter and 12 inches (0.3 m) deep. 

Looped Soaker Hose

You can also use the looped soaker hose to water your grape vines. It is similar to drip irrigation, except it’s much harder to regulate the water released. Nevertheless, it’s great for soaking the soil, especially when watering established plants that need deep watering. 

The looped soaker hose is ideal for small spaces and gardeners looking to save irrigation costs. However, you’ll need to be keen when using the soaker hose because you can easily overwater the grape vines. 

The soil should remain relatively moist during the growing season. Still, it should not be wet because this will encourage fungal root rot.

Signs of Overwatering

Unless you monitor the drip lines when watering grape vines, the chances of overwatering are high. Besides keeping track of water depth and watering duration, the grapevine will also tell you if the water is too much. 

Signs of overwatering include:

  • Yellowing leaves
  • Brown leaf tips
  • Consistently wet soil

If you notice these signs in your grapes, stop watering them for some time. If you have been watering them once a week, with the recommended water levels, you should wait a few more days before watering. For example, instead of once every 7 days, you can extend it to once every 10-14 days. 

This video offers tips on how to water your grape vines:

Signs of Underwatering

Grave vines grow deep roots. Most grape varieties grow roots 3 feet (0.91 m) deep. However, some individual roots can grow up to 30 feet (9 m) deep. These roots sustain the plant during drought, but only for a limited period. 

If they do not get enough water, grape vines will start showing signs of underwatering.

These include the following:

  • No new leaves or tendrils during the growing season 
  • Drooping or curling leaves
  • Leaf bleaching
  • Leaves start falling off 
  • Delayed fruit ripening 

Even though hardy, grape vines need water for vegetative growth, fruit composition, and winter hardiness. If you notice signs of underwatering, you should increase the watering frequency to once every 5 days until you see an improvement in your grape vines. 

Only increase the amount of water if you have been feeding the vines less than the recommended weekly quantity. The risk of deep watering with additional water is you can easily suffocate the roots.

Conclusion

How often you water grape vines depends on the type of grapes, their growth stage, and the climate and soil type in your area.

Table grapes need regular watering without intentional water stress, as is the case for wine grapes. You should also adjust the watering schedule according to the season and the plant’s needs.

Dr. Moritz Picot

Dr. Moritz Picot is a horticulture enthusiast and the founder of TheGrowingLeaf.com, where he serves as the lead content writer. He established the website in 2022 as a valuable resource for both gardening aficionados and beginners, compiling all the gardening tips he has accumulated over the past 25 years. Alex has a passion for nurturing plants, transforming backyards into inviting spaces, and sharing his knowledge with the world.

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