Cultivated grapes are derived from wild grapes that are forest vines. This is important in understanding how to work with grape plants, to give them what they need, so they will give you what you want.
In nature, grapes vines stretch from the forest floor, all the way up to the top of tall trees. Fruit grows only in the parts that reach bright sunlight. The whole point of vineyards is to give the grape plants the sun they need, while setting fruit at heights more convenient to us.
If we could levitate, we might have developed viticulture as a multi-story crop system, with the grapevines growing up through nut trees. We would float around in the treetops at harvest time, gathering the grapes. Once, when I was a teenager in Alabama, I climbed to the top of a tall oak, and picked three pounds of wild muscadine (Vitis rotundifolia) fruit. It was fun, but there’s no way treetop grapes would ever be practical.
At the other extreme, grape vines would grow perfectly fine, let to spread out across open ground. In parts of the desert Southwest, wild grapes scramble over rockpiles, with their roots near springs for moisture. Grape plants would be happy covering a field, but think how hard it would be to pick the fruit, stumbling through those tangled vines.
So grape growing is basically a matter of giving the plants the sun they need, while training them so we can get the fruit. Commercial method are optimized for things like long rows, so machinery can go between, and efficient use of support material. When you look at grape literature, this is what you will see, with lots of details on how to do it. The two ingredients are: Sunshine for the plants. Access for us.
Actually, there is a third factor, critters who want to eat your grapes. I’ll talk about that now, because if you get it right you’ll avoid trouble years down the line.
When I lived in Colorado, I grew grape vines with the stems fanning out up one side of a wooden fence. From the top of the fence, I had support lines spanning to the end rafters on the south side of my house. I trained the vines along these sloping wires. When the plants filled in, they cast a welcome summer shade. The clusters of grapes hung down from this living roof, both picturesque and easy to harvest.
I got away with it for two years. Then the raccoons found it. There was no way to keep them off. They could climb the fence any number of places, and walk along the top to get to the grapes. At first I thought they would eat only the fruit near the fence. But they kept at it, clambering out into the canopy, night after night, till finally they had eaten every grape. At least what they didn’t knock down or ruin.
Basically, I had not thought ahead to make my grapes “defensible”. After years of growing the vines, there was nothing I could do but start over. It happened that I moved to Portland, Oregon, starting over anyway; but now I carefully think about grape supports to prevent problems.
By far the biggest critter problem for home grape growing is raccoons.
Bees and wasps come to the ripe fruit, to get the juice, especially after grape skins are broken by other creatures. But these small fliers are usually minor. If you walk around barefoot, watch that you don’t step on these stinging insects, who scavenge fallen grapes.
Birds peck ripe grapes, but for me their damage has always been minor. Occasionally they may knock down a whole cluster of grapes, while taking only a few.
You might think squirrels would ravage grapes, but I have not found this to be so. A friend loaned me a book on squirrel control. The book made the important point that individual squirrels vary greatly in what they prefer to eat. Or even what they know to eat. For example, I have grown winter squash for many years. I would leave the squashes out late in the autumn, and never had any squirrel problems. Then, one fall, I came home after a weekend away to find half a dozen squashes gnawed open, evidently for the seeds. Immediate harvest of the rest! By the next year, the squirrel who was wise to the ways of squash had evidently died or moved on, and I never had any more squirrel damage.
So it’s always possible a squirrel may arrive in your yard who is mad for grapes. When people see what I do to prevent raccoon attacks, they always think it’s for squirrels. Maybe it’s because squirrels are obvious, and active during the day, and people see them. Raccoons are secretive, and largely nocturnal.
Raccoons are abundant in nearly every urban center in North America. I have heard they are now in Europe as well. I’ve watched them go in and out of storm sewers. They travel through these underground pipes, so they can easily move through neighborhoods without being seen, and without having to cross roads above ground.
It can be easy to miss the fact that raccoons are destroying your grapes. Animals eat only so much at a time. Raccoons come back night after night, incrementally. I would notice a scattering of grapes on the ground, and gradually it seemed there were less and less on the vines. I could easily have dismissed it as squirrels or birds. I wanted to know.
I found you can rig up an old smartphone as a hidden camera, using a motion detector app, so it starts recording video when there is movement. In this way, I proved it was raccoons. They would come by, for only a few minutes, in the small hours long after midnight. They ruined much more than they ate, and the kept coming back till all the grapes were gone.
You can “attack” or “prevent”. I’ll first talk about “attack”, mostly to dismiss it; then move on to the prevention I have found most effective.
Maybe it occurs to you to shoot raccoons. Leaving aside any legality, this is hard to do. You need a gun. You need to watch you don’t shoot something you don’t want to, such as your neighbor’s windows, or your neighbor. If you hire someone to do the shooting, you are going to be paying for a lot of hours. Your agent has to stay awake and stealthy all night, waiting for that brief raccoon visit.
We assume you intend to shoot to kill. You may imagine a certain satisfaction in teaching raccoons a lesson, such as by pellet gun or some such. Most likely, the coon will just wait till you leave, and then come back. Even if you do permanently chase off that particular coon, another one will soon move in.
Much the same goes for screaming, yelling, or trying to stab with pitchforks. There is a continually replenished supply of new raccoons.
Raccoons are hard to poison. They like what they like, and are highly suspicious of anything that smells odd. The best poisons, like strychnine and “1080”, are tightly regulated. Not to mention the risk of off-target poisoning, and the continual supply of new raccoons.
Moving into the zone between “attack” and “prevent”: Electric fencing can be effective, if you can configure it right. You have to close off every point of entry, both on the ground and overhead. You want to avoid shocks to, say, your grandkids, or visitors with pacemakers. Perhaps you can power the system on a day/night timer. Not everyone appreciates the aesthetics of electric fence lines.
You can trap raccoons, but then you have the decision of whether to kill them and dispose of the bodies, or release them somewhere, which will probably already be the territory of other raccoons, not to mention other gardeners. Aside from any legality, both of these take considerable effort.
You can try repelling raccoons with something noxious. This will probably not work, as coons will just step over to get what they want. A neighbor told me raccoons hate the smell of moth balls. Well, they didn’t hate it enough to skip the grapes and cherries. The moth balls did most to repel me.
The only thing that has worked is to set up physical barriers so raccoons simply can not get to the grapes. It may not be obvious what these should be, until you understand what coons can and can not do.
Raccoons are about as agile as cats, but with some differences. They are better climbers through brush, and have more incentive. One time I noticed raccoons foraging in a Cornelian cherry tree (Cornus mas). These trees bear small, tart berries, just what raccoons like. The trees have thin, twiggy branches, which would be difficult for a cat to navigate through. However, the raccoons, with their dexterous, five-fingered “hands” were almost swimming through the canopy.
Raccoons are about as good as cats at crossing a narrow route, such as a two-by-four or similar sized branch, spanning through space. Raccoons are much more able to cross a span they would have to hang underneath than a cat would, or would care to.
Raccoons are not so good at jumping. Cats can spring to the top of six-foot fence. Raccoons can’t get up on a trellis that way; they would have to climb. Cat’s can easily leap across a gap of a few feet. Raccoons are more limited. A gap of a three feet between, say, a tree the coons can get into and your grape supports will probably keep them out.
Raccoons can’t climb an individual year-old grape shoot, but a few vines together can serve as a ladder. Raccoons, especially small ones, might well be able to climb the few-inch-thick “trunk” of a mature grapevine. The shreddy bark gives ample claw traction.
Raccoons can climb vertical wooden posts and tree trunks. They can easily clamber through grapevines growing on a chain link fence. They cannot directly climb the walls of most houses, but they could make use of handholds like downspouts and shutters.
From this you can see that most commercial grape growing systems are cafeteria lines for raccoons. The vines are trained in vertical planes. Even if the lowermost part is above direct reach, coons can easily get up the grapevine trunks, or support posts. In a commercial operation, there are so many grapes that raccoon take might not be significant. However, in your back yard, with proportionally less grapes, you will lose your whole crop.
Above is an example of a grape arbor that has proved coon-proof. The metal sleeves around the posts are key. They are too slippery for raccoons to climb. Notice the sleeves around the grape vine stems too. Training the vines as single stems, and nearly vertical, assures the coons can not get past.
The sleeves look like stove pipe, which I read about in an old book. Stovepipe is impossible to find any more. The sleeves are made of sheet aluminum, which you can get at any hardware store. It won’t rust out like iron stovepipe would.
I am not going to give any particular plans for such an arbor because there are so many different ways to do it. For example, you could use metal posts, that are inherently un-climbable. It’s better if you think it through yourself, based on your particular landscape.
Also, grapevines are wonderfully malleable. Like wild vines, the roots can be one place and the bearing canopy another. You could plant your vine by the dripping downspout, where there’s lots of moisture. Then you could train the vine up to your third-story penthouse patio, and have the canopy there.
The disjoint could be horizontal too. One place I saw, someone had a grape vine planted near the house. Over the years, the vine had run hundreds of feet along a fence till it finally got out from under shady trees, and bore grapes at the back alley.
When you look at the grape literature, you will see all sorts of vine training styles. Understanding how grapes grow is more important than any style. The arbor in my example has the foliage overhead, which is never done commercially. It would take too much ground space, and you couldn’t drive tractors under. But such a thing can be great for home growing. It creates a shady canopy, pleasant to sit under in summer heat.
A point easy to miss in casual descriptions of grape culture is that you chop off huge amounts of the plant each year. You basically whack it back to nothing, just the main trunk and maybe a few branches. You are not being cruel. Grape vines are good at generating great long lengths of themselves in a single season. A wild vine growing in a tree shoots out new growth to get past the additional growth the tree itself has made.
Trees sometimes lose limbs, tearing out a big section of grape vine with it. The grape vine is happy for the extra space, and shoots new growth into the opening, to get more sun. A tree has to build up enough structure to support its own weight, and therefore can’t lengthen very far each year. A vine puts its strength into growing longer, using something else for support.
A wild grape vine in a tree expects to put out new growth every year, seeking the sun. The older growth from previous years gets shaded out in the interior of the tree, and serves as conduit. To do something similar on the ground, you would have to extend your grape trellis as much as thirty feet! Grape growers centuries ago figured out it was simplest to just simulate the limb loss that tears off great chunks of grapevine. They cut off nearly all a season’s growth, so next year the vine puts out its new sun-seeking growth in the same space as before.
Grapes only produce fruit on this new growth. The stronger the new growth, the bigger the clusters of grapes. If you leave a grape vine unpruned, so the vines tangle back on themselves year after year, the new growth get ever more thin and spindly.
There are two factors. First, there are ever more points of growth. The root can only supply so much. The strength is spread over these many points, and each one gets only a little. Also, the many shoots shade each other. Alone, they could grow out faster than tree limbs, but here they are fighting each other. On such a neglected vine there will be few grapes, and they will be small.
This bearing-on-new growth means grapes avoid late frosts. When I lived in Colorado, grapes were my most satisfactory crop. Fruit trees produce their flower buds the year before. They hold them through the winter, ready to bloom in spring. In the up-and-down temperature climate of Colorado, this was a disaster, especially for the early bloomers like peaches and apricots. Spring would come. The trees would bloom. Sometimes fruit would get to the size of little green peas. Then, nine times out of ten, a late cold snap would come and kill all the fruit. No more blossoms till next year. The trees themselves grew great. They never had to waste any strength making fruit.
In grapes, however, the fruit buds are not even there till the new shoots grow out. The flower buds don’t exist yet, and therefore can’t be hurt by frost. As the shoots begin to grow, flower bud clusters form at the leaf nodes. That is, at the point a leaf comes off from the stem. These bud clusters look something like little pale rudimentary bunches of grapes.
These bud clusters will become your bunches of grapes. Now, here is something it took me years to notice. I assumed the grapes formed at random all along the shoots. Probably because I was looking at a tangled canopy. Finally I realized all the grapes grow at the first few nodes, close to where the shoot starts. They may skip the very first node or two, but then the grapes form at the three or four nodes after that. The shoot itself may continue growing all summer, up to thirty feet long, but no more grapes. The shoot is harvesting sunshine, and sending it down to feed the grapes at its base.
There is sort of an exception. If you cut the end off the new shoot, maybe because it’s getting too long and in the way, often shoots will branch out from the part you left. These new shoots will have some tendency to make flower buds at their first few nodes. However, these get a late start, and seldom amount to anything.
This first-few-nodes idea is useful in managing your grapes. For example, you can do something like the picture above. Train the business part of your grape vine trunk as a horizontal scaffold, as shown. Each year, the new shoots will grow out of that. You can see that by the end of summer, the vines may well have grown all over the slatted roof above. However, all the bunches of grapes will be close to the main scaffold, in easy reach. Of course, you need to assure the whole thing is coon proof! Each winter, prune off everything back to the main scaffold.
(Of course this is just one of many possible ways. You can have the scaffold on top of slats or strings, and the grapes hanging through.)
Here is another thing it took me years to realize. When a grape vine starts growing in the spring, shoots try to sprout out from all over; low down, in the middle, and even from the base.
I thought I had to leave them all, no matter how much they might be providing raccoon ladders, or slapping me in the face all summer.
Somehow, I finally got it that grape vines start many more shoots than they need. I could just break off the ones from the wrong places.
This does not take any tools. You just flick them off with your fingers as soon as they appear.
The shoots left get all the strength of the whole vine. In this way you can put the shade canopy where you want.
In the same way you can shape a vine you want to want to get established. In the picture below are some young grape plants. There are a few plants close together, not yet decided which will be the one for the spot. But all of them are putting out a whole series of buds.
If all the buds were left to grow, each shoot would grow moderately. I wanted one to grow as long as possible, to get the vine to established size. So I rubbed off all the buds but the strongest at the top.
In only a few weeks, that top bud has taken all the strength of the vine, and is growing rapidly.
It’s important to support these new shoots. Grapes are vines. They need something to climb on. If a grape shoot grows out into space, with no support, it will snap off under its own weight when it’s a few feet long. This will happen to nearly all of them (except probably the ones you don’t want).
A rule of thumb is that the canopy of each grape vine will be something like 100 square feet. Of course vines can overlap and share the same structure, but keep in mind the size. Varieties of grapes differ in vigor. Some are delicate, and will never get that big. Others are much more robust, and will spread to several times that size. Try to research varieties you are interested in, or go look at existing plants to know what to expect.
It can be hard to believe that a small, spindly grape plant growing from a cutting will finally be a big vine, heavy with fruit. The rule of thumb here is that any trellis or arbor should be at least strong enough that you could reach up and grab on to it by your hands, and hang from it with your full weight. Slats and strings that crisscross within won’t need to be so sturdy, but a grape vine can weigh hundreds of pounds. When fully leafed out in summer, it will also take a lot of force from the wind. A structure too flimsy will collapse, or blow down.
You, of course, do not need to build a complete structure when you first plant a grape vine. If you grow it from a cutting, it may need no more than a bamboo pole for support the first few years. Raccoons will have no interest until there are ripe grapes. But don’t paint yourself into a corner. Plant grape vines such that you at least can support and critter-proof them when they mature. Once a grape vine gets going, it can much more than double in size each year.