Growing a few grape vines around your house is a different proposition than a commercial vineyard. Much of the information you will find is geared towards large-scale production. In this post, I am going to concentrate on backyard growing. There are significant differences in focus, both in propagation techniques, and in training the vines.
You start a new grape vine from a “cutting”. A cutting is simply a section of grapevine. You get roots to grow from the bottom, and leaves to grow from the top, and then you have a new grape plant. Grapes will grow from seeds (except of course seedless grapes), but you’re not sure what you’re going to get. To propagate a certain variety, you want to use cuttings.
In grape growing, you prune off a considerable amount of vine each winter. This naturally provides material for cuttings. Most information about grape propagation is geared towards these winter cuttings, made from dormant, leafless vines. I’ll discuss these, but also alternatives.
To start a sizeable vineyard, a grower would, of course, be dealing with a great number of cuttings. The easiest way to get these is to section up the prunings from existing vines. So a lot of grape propagation information concerns the mass organization, storage, and rooting of these winter cuttings. On a backyard scale, however, not all these points apply.
To divide out a section of vine to make a cutting it takes, of course, two cuts. One is the lower cut, which will be the bottom of the cutting, where roots will grow. The other is the upper cut, the top of the cutting, from which the leaves will develop. In large scale propagation, it’s handy to be able to tell these ends apart at a glance, and so a tradition has come about: The lower cut is straight across the vine, just below a node. The upper cut is angled, just above another node. If you receive grape cuttings, they will usually be done this way. If you are dividing up grapevines to make your own, it’s a handy grammar. However, you don’t have to strictly follow this.
Cuttings are usually made with at least three nodes, such as the one on the left in the picture below. This gives nice strong cuttings. You may be surprised how long three-node cutting are. You may have a hard time finding a place to store them. You may be bringing some home in your airline luggage. You may have difficulty digging a hole deep enough to plant them. So, if you are making cuttings, and length is a problem, you can make two-node cuttings, like the one in the middle of the picture. (Click on the picture to enlarge.)
It’s fine to have more nodes, such as the four nodes of the cutting on the right.
I have had one-node cuttings grow, by accident. When I prune my grape vines in winter, I just chop up the small stuff with my pruners, and let it fall on the ground. Usually, a few pieces happen to land among the garden plants just right, and get watered just right, so that some time the following summer they start to grow. Roots come out below the node, and the node bud opens out into leaves. So, if one little section of grape twig is all you can get, you might be able to grow a vine from it.
Commercial propagation consists of bundling up the grape cuttings for winter storage, and then getting them to grow in the spring. You may read about technique such as burying them in sawdust or sand, using rooting hormones, burying bundles upside down, and using bottom heat in a propagation bed. I’ll explain what these are about, and how they apply, or don’t, to home propagation.
The basic issue of storage is to keep the cuttings alive, and keep them from sprouting too soon. The main reason cuttings would die is from drying out, thus the burying in damp sawdust or sand. This is reasonable for large bundles, but there is no reason for you to go get these materials for only a few cuttings. You can just keep your cuttings in vegetable bags, like any other produce.
As I’ll describe later, you can start your cuttings growing in the winter. But then you are faced with the problem of keeping the plants healthy until spring when they can go outdoors. So, unless you particularly want to do this, you should keep cuttings cold, so they stay dormant. If you have only a few cuttings, you can keep them in your refrigerator. For more, you can store them outside.
Freezing is not particularly a problem for grape cuttings. Any variety you are planning to grow, which is hardy in your climate, can stand up to your winter temperatures. However, in continental climates, winter weather is often very dry. Therefore, grape cuttings left out on the open ground can dry out. A convenient way to both avoid this, and keep the cuttings organized, is to slip them into plastic vegetable bags, and tuck these under a few inches of dead leaves or other mulch. In a mild, wet-winter climate like the Pacific coast, you don’t even need to bury them. Grape cuttings may be too long for a single bag. You can use two bags, one “telescoped” inside the other.
If you have plenty of cuttings available, the easiest way to start a grapevine is simply to plant a number of cuttings close together where you want your vine.
Here, I put eight cuttings close together. This was in early March, but you can do it any time in winter the ground is not frozen. I did not use any rooting hormone, or other treatment. The ground was so stony, I could not plant all of them as deep as ideal, which would have been with only the tip above ground.
Still, six of the eight cuttings grew. This picture is from the following December.
The point of this technique is that, even though some of the cuttings die, you still get a grapevine going. Just pull out the dead ones and the extras, and leave the strongest. If you have lots of cuttings, which you will if you have an existing grapevine, or know someone who does, this is by far the easiest way to start a new one.
Incidentally, there does not seem to be any pattern to which cuttings take hold. In this case, the two that died, out of the eight originally planted, looked just as strong and promising as the ones that grew.
This multi-cutting method does not, of course, make sense for a large-scale planting. For that, you want to be pretty sure each cutting will grow, so you can line them out in rows and end up with a vineyard. From cuttings just stuck in the ground, I have always had more than 50% grow, typically 75%. But that’s nowhere near good enough for commercial production. Filling in 25% gaps would be a lot of effort. It would be almost as much work to take out the extras, from mutliple cutting planted at each spot.
The propagation techniques you come across in the grape literature are all about increasing the odds per cutting, so you get one grape vine from each thing you plant. For home-propagating a few vines, these techniques may not apply. If you have lots of cuttings, you can get away with a low per-cutting success rate.
But what if you have got ahold of only one precious cutting, which you absolutely must make grow? Maybe you had to pay a lot for it, or it was all the source could spare. Maybe it came from halfway around the world, and you will never be able to get another. I stumbled on a simple, inexpensive technique that, for me, has given 100% success: Root them in water.
Nowhere in all the propagation literature had I ever heard of rooting grape cuttings in water, but it works quite well. It allows you to carefully monitor progress, as well as being interesting to watch. It would be far too much fuss for mass production, but it’s ideal for a few.
Just put your cuttings in jars that have some water. Change the water if it gets too murky. Because there is plenty of water, the cuttings cannot dry out and die, unless you let the water dry up. You can put the jars outdoors, in direct sun, so any leaf growth is firm and strong.
If you look close at the picture above, you will see that the source of the cuttings did not much follow the “grammar” of number-of-nodes, and straight- and angle-cuts. But the cuttings are rooting just fine. The conventional wisdom is that grape cuttings grow roots from the nodes. However, as you can see, the roots are coming from the bottom of the cuttings, ignoring the nodes. Cuttings do have a tendency to put out more roots near nodes, but this is by no means strict.
Cuttings with roots at this length are ready for planting. Short roots like this are called the “rice” stage; little white rods like grains of rice. Roots let to grow to the “spaghetti” stage are more prone to break off. Longer roots don’t give much advantage in water absorption. They have to develop a new set of root hairs, from additional growth, before they can supply much to the plant.
Virtually always, cuttings in water will have leafed out by the time they root. This is the main thing you will have to fuss over.
Roots absorb water, and leaves expend it. A typical scenario is this: Grape cuttings are planted out during cool, wet weather. They look fine, the foliage fresh as lettuce, as long as the rains remain. Then, one day, the weather turns hot and sunny. The roots can’t keep up, and the leaves shrivel. In the extreme, the whole thing may die. It can also happen that the leaves shrivel up, but the cutting hangs on till it finally makes enough root growth to put out new leaves. Although a cutting like this may survive, it will be set back, and not make nearly as much growth in its first year as a cutting without this hardship.
What to do? Simply shade a newly planted cutting until it adapts. You can rig up special shaders in various way, but often the simplest thing is to just put a lawn chair on the sunward side of a new grape cutting. This would be on the south side in the northern hemisphere, on the north side in the southern hemisphere. A cutting can handle as much indirect sky light as there is, and it won’t have much trouble with morning and evening sunshine. It’s direct mid-day sun will that will dry it out.
You only have to shade a new cutting for a few days, or a few weeks at most. Soon the roots extend and send more water up to the top. The leaves grow and send food down to the roots. And the plant is in business.
Up till now, we have been talking about cuttings from winter-dormant vines. I found by accident that you can root green leafy summer shoots.
Once, I had a chance to get grape cuttings of a variety I wanted to try, but it was midsummer, not the usual time. I kept the cuttings in water, intending to study them. After some weeks, I noticed they were growing roots.
This can take quite a while. In this case it was September, and by then the shoots had dropped their leaves. But I had a rooted cutting I could plant.
Later, I saw summer grape cuttings being propagated in a university research greenhouse. These were two-bud cuttings, and half of each leaf had been removed to reduce water loss. The cuttings were under an “intermittent mist” system, which is a method that works very well, but it rather complex to set up. So, if there is a variety of grape you want to try, and the only time you can get cuttings is when they are fully leafed out in summer, you can get fairly good success by rooting them in water.
For various reasons, you may need to transplant a grape vine. If at all possible, do this while the plant is dormant and leafless. Leaves lose a lot of moisture.
In my experience, you can transplant a grape vine of any size, but a mature plant will be set back for about a year. It will take hold, as though it were a large, rooted cutting, but it will put out less growth the first year after transplanting, and produce fewer grapes. A large grape vine can be quite physical to wrangle, so take this into account in deciding whether you want to move a vine, or simply start a new one. You can have grape vines in full production, from cuttings, in three years.
Below is a picture of a one-year-old grape plant, dug up for transplanting. This grew from a cutting merely stuck in the ground, with no other help than regular watering. It is typical for a vine to make only a few to several feet of top growth the first year. It’s developing lots of roots, getting ready to take off following year. Now, there is more root than top.
Grapevines typically have a root system that consists primarily of relatively few long, snakey roots, rather than much of a root ball. Notice the plant in the picture: Even though more roots started from near nodes, the strongest root came from between nodes. This is just the way it happens sometimes.
Grapes are mostly woodland plants, where their roots have to compete with trees. Their roots grow long, to seek out what they need. For the backyard grower, this means that after a few years, you are going to be finding your grapes’ roots many yards away, mining water and nutrients from whatever garden beds they can get into. Be aware of this when choosing a planting site.
Grapes do fairly well with their roots under a lawn, but be aware of what this can mean. For some years, when I lived in a dry climate in Colorado, I grew grapes on the chain link fence that bordered my neighbors. The neighbors were much more lawn conscious than me, so the grapes put most of their roots over there, where they could get more moisture. Then, at one point the neighbors were going to sell their house, so in order to spruce up the lawn, they sprayed weed killer. The grapes took it up, and nearly died!
You can of course grow grapes in pots, but they are not naturally adapted to this.
This picture is of some grape vines, in their first summer, developing from rooted cuttings. It is only July, and the plants are already getting to unmanageable size. If they were in the ground, the roots would have extended at least as long as the vine top growth. But here, the roots are having to spiral around and around inside the pots. These plants are sustained by drip irritation, and their water demand is only going to increase. If the moisture were ever interrupted, the plants would be severely stressed.
Of course nurseries only sell grapes as potted plants. Typically, these vines are fairly small. If they had been let to grow large in pots, they would be significantly potbound. They are going to have to stretch out their roots some time. If possible, let them do it from the start.
Now, I would like to demystify some of the grape propagation information you are likely to come across. Often, terms are given without any definition, and techniques are stated without any reason why.
You may come across the term “callus” in grape propagation. Callus is whitish cauliflower-like growth that plants may form in the process of re-organizing their tissues.
Some varieties of grape develop a considerable amount of callus, which serves as a signal that roots are on the way. However, others grape varieties make no visible callus before roots pop out.
The propagation literature may recommend a certain operation to “callus” cuttings; that is to nudge them towards creating roots. This is what “callus” means, used as a verb. Keep in mind there may or may not be any visible change.
The main reason grape cuttings fail and die is that leaf growth outstrips the moisture roots can supply. Most of the details of large-scale grape propagation are to get around this problem, so a higher percentage of the cuttings succeed, and a vineyard planting will requires less fill-in afterwards. Again, this is less important for a home grower, but it’s the reason behind the recommended methods.
A bud is ready-made. All it needs to do is open and put out leaves. However, for a grape cutting to grow roots, it has to re-organize its tissues to create these. Different varieties of grapes vary in the time-lag it takes them to do this. In the extreme, you can get a leafed-out cutting that still has no roots at all. To improve on that, you want to speed up the formation of roots, relative to top growth.
Rooting hormones act as “auxins”, which are a type of naturally occurring plant hormone. Plants produces auxins in their growing shoot tips, and the auxins are transported downward through the stem. If the stem is cut off, the downward travelling auxin accumulates at the cut end and stimulates the tissues to re-organize into roots. There’s more to it, but that’s the general mechanism.
This explains why reluctantly-rooting grape cuttings will finally get around to growing some roots when the buds open. The growing shoot tips produce more auxin. This is how the water method works. It provides life support until roots grow, no matter how long it takes.
Rooting hormone is simply externally supplied auxin. Much like natural auxin, it moves downward through the stem and accumulates at the lower cut end. The usual mode of application is by dipping the rootward end of a cutting into a powder or a solution, so the hormone starts near to where it’s needed. Then the cutting is planted in a soil-like medium.
It’s an open question whether rooting hormone would help cuttings root in water. Would the auxin accumulate in the water and help? Or would the water dilute it, and lessen its effect? From the product standpoint, this is usage beyond its specifications. From the plant standpoint, grape cuttings root fine in water without it.
Another aid to rooting is “bottom heat”. All else being equal, plant life processes go faster at warmer temperature. If we were to keep the bottom of the cutting, where we want roots, warmer than the top, the lower end should grow roots while the top is still dormant.
This is, in fact, exactly what happens. Bottom heat is much used in commercial propagation. However, when you start looking into it, you will find it amounts to considerable outlay in effort, equipment, and expense. You will have to decide if the investment is worth it for a few grape cuttings.
The idea of burying bundles of grape cuttings upside down for some period of time is to use nature as bottom heat. Since soil warms in the spring from the top down, this will make the root ends of the cuttings warmer than the tops. This technique could tip the balance in large-scale commercial production, if the weather and climate cooperate. However, think for a moment what’s involved in digging holes big enough to bury long bundles of grape cuttings. Not to mention, digging them all up later, to plant right-side-up. There is no reason to do this, to start a few new plants.
I have tried various things with water, to get roots while buds were still dormant. One time, I used winter-dormant cutting in late fall. I put them in water, in an indoor growth chamber about 70 degrees F. I knew that most deciduous plants have a “chill requirement” and the buds won’t open until a certain time period of cold weather has elapsed. I figured I could get roots, with the buds still closed.
Well, the plants had their own idea. The cuttings rooted well, but the buds opened too. By January, I had healthy, actively growing grape plants. Again, unless you particularly want these decorations, you should keep your cuttings cold, and dormant, till spring.
I tried the bottom-heat idea, with water. My system involved an aquarium heater, in the refrigerator. The bottom ends of the cuttings were held at about 78 degrees F, while the tops remained about 40F. This worked, to some extent, but it was a huge amount of trouble.
Coming soon, part two, grape vine training.