We have a grapevine growing up our patio overhang and while it was doing well, it’s beginning to fall over and die. To help fix this, I did some research. Here’s what I found causes grapevines to die (and how to fix it).
Grapevines most commonly die from improper watering, climate, and nutrients, as well as certain pests and diseases such as Japanese beetles and root rot. For best results, only water grapevines when the top 2-4 inches of soil is dry, and apply compost and mulch. Also, grow grapevines in USDA hardiness zones 4-10.
So, while several issues lead to dying grapevines, how can we tell which issue is causing it, and from there—how can we fix it? Let’s take a closer look.
Can a Dying Grapevine Be Saved?
Dying grapevines can be saved if the issue isn’t too severe and is caught early on. It all comes down to the grapevine and if it has enough energy to survive and regrow. If not, the plant will likely decline until it dies. The good news is that most conditions are fairly easy to reverse, especially with the right approach.
If you’re new to grapevines, keep in mind they’re deciduous plants, so it’s normal for them to go dormant in the fall and winter and lose all of their leaves.
However, if your grapevine is losing leaves in the spring or summer, or has other concerning symptoms, read on for what we can do to fix it.
3 Quick Steps To Save a Dying Grapevine
If you’ve already tried finding out which issue your grapevine has, and you’ve gotten stuck, there’s still hope.
Here are 3 steps you can use to save your grapevine, for just about any condition.
1. Identify the Possible Issues
The first step in reviving a dying grapevine is to identify the possible issues. After all, the process of elimination wouldn’t work if we didn’t know which options we were eliminating!
If you haven’t seen them yet, reference the below sections for the top 6 most common grapevine issues.
2. Isolate the Actual Issue
Once you’ve checked the specific symptoms your grapevine has, you can now cross off potential issues from your list.
Try to get it down to 1-3 potential issues that best match the symptoms your grapevine is exhibiting. This will give you the best chance to provide the right solution for it (you don’t want to repot the plant if the problem is a watering issue).
If you’re still not sure about the issue your grapevine has, that’s okay! Call up your local nursery and get their opinion on what’s happening.
You may need to talk to a few people to get their experience, but there’s a strong chance they’ve seen it before and can point you in the right direction (or even provide you with the solution!).
Additionally, you can contact your local professional orchard or cooperative extension service.
3. Test Solutions
Now that you have a narrowed-down list of the potential issues, it’s time to try the solutions one at a time.
Start with the least invasive solution and work your way up to the most invasive. Again, it’s much easier on the plant to provide less water than to repot or transplant it. Try to save those options for last.
Continue testing the treatments you believe are most likely to fix the issue. And hopefully, one of them sticks.
Worst case scenario, start from step 1 and make a new list of possible issues. There’s a chance you might have missed something or you notice something new the second time around.
Stay persistent! It’s easy to say, “Dumb plant, why don’t you want to live?”, but there’s always a reason why plants act the way they do. Stay the course and see if you can uncover it.
Now, to give you a head start on treating your grapevine, let’s look at the 6 most common reasons why grapevines die.
The Top 6 Reasons Why Grapevines Die
1. Under-Watering
Most vineyards are in hot and dry climates, so it’s no surprise that under-watering is one of the top reasons grapevines die. You can tell if your grapevine is under-watered if its leaves begin to droop, curl, dry, brown, and drop.
While watering grapevines can be challenging, there are some tricks to make the process much easier.
The best way to water grapevines is to only water when the top 2-4 inches of soil is dry. You can check this by pushing a finger into the soil, under the grapevine’s canopy. Ideally, the soil should have similar moisture to a wrung-out sponge.
When watering your grapevine, soak the ground down to 2 feet as over 90% of the grapevine’s roots are found at this depth.
Additionally, provide 2 inches of compost and 4 inches of mulch for dramatically improved soil moisture.
Compost provides valuable nutrients and improves the soil’s richness. Every 1% increase in the soil’s richness or organic matter leads to an additional 20,000 gallons of water held per acre (source).
Mulch is great at reducing evaporation, regulating soil temperature, and preventing soil erosion. Since grapevines evolved as vining species in forests, they prefer a trellis, partial afternoon shade, and tons of mulch. In forests, this meant copious amounts of leaves and branches covering the soil.
Reapply compost every 1-2 months and mulch every 3-6 months. Avoid placing these materials within 3 inches of the grapevine’s main or terminal stem as they can introduce mold.
Recommended: 10 Expert Tips for Watering Fruit Trees
But what if your grapevine’s soil is staying sopping wet for more than a day?
2. Over-Watering
Over-watered grapevines are most common with poorly draining soils (such as those with heavy clay). While it is possible to over-water grapevines in well-draining soil, it’s much less common and would require very frequent watering.
Symptoms of over-watered grapevines include leaves drooping, yellowing, and dropping. Occasionally, grapevines will drop green leaves.
As with under-watering, the best way to avoid over-watering is to only water when the top 2-4 inches of soil is dry.
However, watering properly is difficult if your grapevine’s soil has poor drainage.
Poor Drainage
Poor drainage is usually caused by compacted soils or those with heavy clay content. Since clay particles are much smaller than sand or silt, they easily form a tight layer that allows little to no water to pass.
To help show the various sizes of soil particles and their effect on drainage, check out the graphic below.
The best soil for most plants, including grapevines, is loamy soil. This is a balance of all three soil types.
Loam is difficult to obtain in many cases (especially in damaged soils), so it can take some time to amend.
It’s best to first determine which soil type you currently have, and then you can figure out what you need to add to improve it.
For starters, here’s a quick breakdown of the different soil types.
| Soil Type | Pros | Cons |
|---|---|---|
| Sand | Good drainage | Doesn’t hold nutrients well |
| Silt | Holds nutrients well | Poor drainage |
| Clay | Holds the most nutrients | Even worse drainage than silt |
What’s interesting is that poorly draining soils and fast-draining soils have the same solution—to increase the soil’s organic matter (compost). Organic matter not only breaks up the clumps of poorly draining soil but provides ideal water retention (not too much and not too little).
No matter the drainage, apply 2 inches of compost every 1-2 months.
However, in poorly draining soils, avoid mulching until the soil is well-draining. This is because mulch traps moisture and reduces evaporation—making poor drainage worse.
I could go on in more detail about soil types and drainage tests, but I found it’s usually better to see it done.
So, check out the video below by Growit Buildit on how to test soil types and perform a percolation test.
I did this same method in our backyard and it didn’t take long at all (we dug three different holes to get a better sample of our entire backyard’s soil).
These fairly quick tests help to know your soils and what’s lacking or in excess!
3. Extreme Weather
Grapevines grow best in USDA hardiness zones 4-10, but some varieties such as Valiant can be grown down to zone 2.
Cold weather isn’t much of a problem for grapevines as they tolerate temperatures -20ºF and below (the average minimum temperature for zone 4).
As a result, they’re more often affected by hot and dry weather.
In temperatures 90ºF or higher, grapevines begin to lose more moisture than they can accumulate. Symptoms of excess moisture loss show as leaves drooping, curling, drying, browning, and dropping.
This issue is compounded if grapevines are lacking water.
To help solve this, it’s beneficial to know how grapevines keep themselves cool in the first place.
Grapevines primarily cool themselves by sending moisture from their roots to their leaves, and by a process called transpiration.
When humans exhale, we release moisture, and plants do the same. This is called transpiration and it’s the reason why walking into a forest or a thick canopy can feel extremely humid.
In his book, The Hidden Life of Trees, professional forester Peter Wohlleben describes leaves as having two parts. The topside of the leaves functions similarly to a solar panel, creating sugars via photosynthesis, while the bottom of the leaves respirate (transpire).
So, when the weather is too hot and dry, the plant’s root moisture and transpiration can’t keep up and cool the plant, causing the plant to decline in health. If the weather is too extreme, the grapevine can become greatly damaged in a single afternoon.
Here are some ways we can prevent grapevines from getting too hot and drying out.
Tips for Hot Weather
- Apply compost and mulch. As mentioned earlier, compost and mulch provide so many benefits, not just for nutrients, but for water retention and soil temperature regulation.
- Provide partial shade, especially from the western sun. Since the afternoon sun is much hotter than the morning (eastern) sun, partial shade can go a long way to keeping the grapevine cool. Grapevines evolved growing up the trunks of large trees such as oaks, so they’re used to and prefer some shade.
To learn more about using oaks and other plants to assist grapevines (with shade, nutrients, and more), check out these grapevine companion plants.
4. Improper Nutrients
Excess Nutrients
Chemical fertilizers that have high amounts of nitrogen often stress the grapevine’s roots, causing leaves to discolor and drop. If it’s bad enough, the entire plant will die.
This is especially true for fertilizers that are fast-releasing. These potent fertilizers can quickly burn the grapevine’s roots, causing it to redirect energy from growing and reproducing (flowering and fruiting) to surviving the burns.
Generally, compost won’t cause either of these issues as it’s not potent enough.
Pro-Tip: Fertilizers high in nitrogen encourage grapevines to focus on foliage growth (as nitrogen is the main nutrient used), instead of flowering and fruiting.
Lack of Nutrients
All plants need three main nutrients: nitrogen, phosphorus, and potassium (abbreviated as NPK). Without these nutrients, grapevines get symptoms such as leaves, flowers, and fruit discoloring and dropping.
To summarize the roles of NPK:
- Nitrogen is the primary nutrient, and the one responsible for foliage growth
- Phosphorus is a key nutrient in flowering and fruiting
- Potassium is vital to maintain the health and immune system of plants
While phosphorus is the main nutrient in flowering and fruiting, other nutrients such as potassium make it possible. So, avoid solely adding phosphorus to your grapevines.
Plants also need secondary nutrients such as magnesium, zinc, and iron.
Fortunately, most fertilizers and composts have sufficient primary and secondary nutrients. However, there are times when the grapevine’s soil could be lacking.
To help you diagnose the most common nutrient deficiencies with grapevines, check out this quick table I put together:
| Nutrient Deficiency | Leaf Symptom |
|---|---|
| Nitrogen | Entire leaf is pale or yellow |
| Iron | Dark green veins, rest of the leaf is yellowing |
| Zinc | Yellow blotches |
| Manganese | Broadly pale leaves, foliage color looks mottled or smeared |
The Best Fertilizer for Grapevines
Ideally, provide grapevines with an acidic fertilizer or compost.
However, many gardeners are finding compost is replacing fertilizers for them. This is because chemical fertilizers commonly lead to long-term issues such as dry (dead) soil.
On the other hand, compost provides more than sufficient nutrients and promotes beneficial soil life (such as earthworms and mycorrhizal fungi). This soil life has valuable benefits such as increased water retention, disease resistance, and pest resistance.
Mycorrhizal fungi promote many aspects of plant life, in particular improved nutrition, better growth, stress tolerance, and disease resistance.
Department of Biology, University of Fribourg, Switzerland
Either option you choose, you can see my recommendations on my recommended fertilizer page. Aim for an acidic fertilizer if possible as grapevines prefer a more acidic soil pH.
Soil pH
Without a balanced soil pH, plants are unable to properly absorb nutrients from the soil. Many plants require a slightly acidic pH as it dissolves the nutrient solids in the soil.
Fourteen of the seventeen essential plant nutrients are obtained from the soil. Before a nutrient can be used by plants it must be dissolved in the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or slightly alkaline soils.
Donald Bickelhaupt, Instructional Support Specialist, Department of Forest and Natural Resources Management
Grapevines do best with a soil pH of 5.5-6.5. Generally, American grape varieties prefer a pH closer to 5.5 while European varieties prefer closer to 6.5.
To measure your soil’s pH, I recommend using pH strips or a meter. I prefer using a meter since they’re affordable and easy to use. To see which pH meter I use and recommend, check out my recommended tools page.
If you find your grapevine’s soil is too acidic (under 5.5), provide alkaline amendments such as wood ash, charcoal, or lime. On the other hand, for alkaline soil (above 6.5), provide acidic amendments including sand, peat moss, and coffee grounds.
5. Over-Pruning
Over-pruned grapevines result in a lack of leaves necessary for photosynthesis. Because of this, the grapevine is unable to gather a proper amount of sugar to feed itself, causing little to no flowering and fruiting. If severely over-pruned, the grapevine can die.
However, when done right, pruning can dramatically assist with fruit production.
Pruning is not a necessary practice, but it’s helpful to:
- Encourage more fruiting
- Promote more sunlight and airflow
- Manage and prevent pests and diseases
- Shaping the plant into the desired appearance
Many grapevine growers prune their plant’s overlapping and excess branches to promote more and heavier fruiting. This works incredibly well as the plant has fewer branches and leaves to feed and can feed its flowers and fruits instead.
Ideally, prune grapevines in the late winter as pests and diseases are inactive and are less likely to infect the open wounds from pruning.
6. Pests and Diseases
| Common Pests for Grapevines | Common Diseases for Grapevines |
|---|---|
| Grape Phylloxera | Leaf Spot |
| Japanese Beetles | Tar Spot |
| Grape Berry Moths | Armillaria Root Rot |
| Mealybugs | Mildew |
| Hoppers | Verticillium Wilt |
Grapevines can die from pests and diseases such as Grape phylloxera, Japanese beetles, leaf spot, and root rot. Treat pests by using organic insecticides or companion plants, and diseases with organic fungicides.
You can generally tell if a grapevine has pests by inspecting the leaves and the fruit. You should be able to see the pests themselves or signs of the pest such as holes in the leaves or fruits.
To see more about pests and how to treat grapevines, check out this resource by the University of Minnesota. You can also reference this resource by napagrowers.org.
On the other hand, diseases are typically shown as yellow, red, or brown spots or blotches on the leaves and other parts of the vine.
To see a full list of the diseases grapevines get and how to treat them, check out this resource by Michigan State University.
A Note on Pesticides and Fungicides
My parents recently had an issue with caterpillars eating their basil plants in Ventura, CA, and they were about fed up. Every time they’d plant basil, the caterpillars ate it. Fortunately, instead of giving into chemical sprays, they found an organic spray at their local nursery that’s made from fermented rum. The day after spraying, they’d find dead caterpillars on the soil.
If you’d like to find out more about this organic spray, you can find it here on Amazon.
So, what’s my point here?
Even though chemical sprays and fertilizers are an easy way out, like all easy and convenient things, there are usually long-term costs. Namely to the plants, soil, and surrounding beneficial life. Before using conventional sprays, weigh the pros and cons and consider trying organic or permaculture-based treatments first.
To give you a head start, Stefan Sobkowiak – The Permaculture Orchard has a great video on a safe, homemade, and most importantly—effective fungicide (hint: the secret ingredient is whey).
Also, check out how Mark Shepard uses a method called STUN (Sheer Total Utter Neglect) to help his berry plants, fruit trees, and nut trees THRIVE.
Final Thoughts
It turns out that our grapevine was suffering from hot weather and over-pruning. After giving it more regular water and allowing it to regrow, its condition started to improve.
By following the above 3 steps (and referencing the top 6 most common issues), you should be able to troubleshoot just about any issue you’re having with your grapevine.
