Category Archives: viticulture

Summer Heat And Water Stress

I wrote before that watering my bonsai vineyard can be tricky. Too much water reduces the quality of the fruit and can delay dormancy. All plant life needs water, however, and too little can harm the vine. If you’re growing grape vines in pots, none of the local knowledge about climate, soil, and irrigation apply. All the research, that growers have access to, wont help you. I had been watering once a week, and keeping an eye out for water stress. Well, yesterday I found it. The one and only cluster on my Swenson Red is shriveled, dry, and dead. Maybe I just don’t have a good eye yet, but I didn’t see any signs of trouble; the leaves and tendrils looked fine. The other vines look to be in good shape, but I took this as a warning and I now intend to water twice a week. I learned something about my bonsai orchard too.

I had been treating the fruit trees, I also grow them in pots, just like the grape vines. I’m still curious about how some viticultural techniques; like leaf pulling, cluster thinning, and withholding water during fruit maturity; might apply to other fruit that’s being grown for wine. My fruit trees haven’t been doing well on the strict watering regimen, though, so even if they can benefit from the ways of grape growers, I’ll have to be careful to give them enough water.

Leon Millot: From flowers to fruit

The flowers have given way to immature fruit.

Leon Millot fruit set on 6/21/07

I took this photo on 6/21/07 and you can (only just) see that the flowers have faded leaving the beginnings of grapes behind. What you can’t see are the hoplia beetles, they left with the flowers and have moved on to the Pinot Noir.


A nearly ripe cluster of Siegerrebe grapes has turned to a vibrant shade of pink-red.

Oz Clarke describes Riesling, in his Grapes and Wines, as the “teacher’s pet” of grapes. “I wonder what it feels like,” he asks, “being the wine experts’ favorite grape, yet failing to excite the palates of the vast majority of wine drinkers across the world?” Well, Siegerrebe doesn’t have that problem; it is most definitely not the wine experts’ favorite grape. Mr Clarke, presumably saying nothing because he has nothing nice to say, doesn’t mention this Gew├╝rztraminer and Madeleine Angevine cross at all. The nicest thing that Jancis Robinson’s Oxford Companion to Wine had this to say about it is, “The variety can usefully bolster some blends in England.” But she doesn’t just damn with faint praise, calling the wine flabby, oppressively flavored, and a chore to drink. Now that’s a lady who speaks her mind!

All this reminds me of a cartoon about a couple discussing a movie. The girl reads off a list of negative reviews – one star, two stars, thumbs down, etc, “It’s a good thing we saw those,” says the guy, “Yeah,” agrees the girl, “we might have seen the movie and liked it by mistake!” I’m glad I didn’t read Ms Robinson’s comments until after I tried the wine myself, because I might have ignored it by mistake. I liked the Whidbey Island Winery’s Siegerrebe enough to grow the grape in my bonsai vineyard. It grows well and ripens early in this climate, that puts it on a pretty short list of grape varietals, and I like the wine. Maybe this is just a case of an obscure grape finding a place where it can shine.

Leon Millot Blooms – Hoplia Beetles Feast

First the good news. The Leon Millot are blooming!

Leon Millot blooming on 6/12/07

I took these photos on 6/12/07, though I first noticed that the Leons were blooming on 6/6/07. The next photo shows the bad news: Hoplia Beetles love to eat flowers, including grape flowers.

Leon Millot beset by Hoplia Beetle

At least I think they’re Hoplia Beetles. They fit the description in Jeff Cox’s From Vines to Wines, they’ve shown up at the right (from their point of view anyway) time, and they’re found mainly in the West.

I’ve been going out to the bonsai vineyard every day with a bucket of soapy water. By holding the bucket underneath the cluster they’re feeding on and giving it a tap, I drown the greedy little bugs. I’ll try to control them this way, but I’m looking into chemical controls in case it doesn’t work.

Bonsai Vineyard: Watering and fertilizing

Advice on fertilizing and irrigating conventional vineyards is often easy to come by, but the rules change in a bonsai vineyard where you plant grape vines in pots and trim the roots every year. You must supply water and fertilizer to keep the vines healthy and to get a good crop. The key question is how much.

Grapes are famous for growing in poor soil, and it’s easy to over fertilize. The excess vigor can encourage vegetative growth at the expense of fruit and make the vine hard to manage. Over watering can be a problem too, especially late in the season when the vines are ripening fruit. Excess water will find its way into the grapes, leaving the grower with great looking plump fruit that is unsuitable for making wine. This is why growers often withhold water late in the season.

Vines in a conventional vineyard can send their roots deep into the ground in search of nutrients and water, so they’re almost never cut off the way a potted vine can be. My approach is to always water with a dilute solution (about a tenth of concentration recommended for outdoor plants) of complete fertilizer, like Miracle-Gro, then water according to where we are in the season and what the vine needs. When the vine is growing and demanding water, it gets more fertilizer. Late in the season after most growth is finished and the vine is preparing for dormancy, it gets much less. This simplifies the problem by reducing it to one question, “how much water does the vine need?”

Unfortunately, I can’t give a one-size-fits-all answer like this many gallons (or liters) per week. I usually start with a tentative schedule, like watering (until the well drained soil is thoroughly wet and just starting to drip through the drainage holes) once a week, and watching for signs of water stress to see if I need to supplement. Are the leaves and tendrils strong or limp? Does the soil dry out very quickly? These signs would push me to provide more water. If it’s early in the season, I have a bias toward more water. Later in the season I might tolerate some water stress to avoid over watering. The ripening fruit gives clues too. Firm bulging grapes look terrific, but don’t make great wine and indicate too much water. If the fruit starts to shrivel, like raisins, then you’re at the other extreme of too little water. If you know how to listen, your vines will tell you.

Cluster Thinning For Better Wine

In yesterday’s post, I mentioned that my Pinot Noir clone, ESP374, is not highly regarded. Its biggest problem is that it sets more fruit than it can ripen well. It over-promises and under-delivers, and, ever the optimist, does the same thing year after year. To make good wine from this clone, I pluck out immature grape clusters until there are no more than the vine can ripen. It’s called cluster thinning, and most vines can benefit from it. But how do you know what the right number of clusters is?

There’s the expensive way: you can hire someone else to tell you. There’s the cheap way: you can ask another grower in your area. There are also rules of thumb published in books and on the internet. All of these answers will be for vines, planted in conventional vineyards, that are free to grow their roots as far down as they like. In fact, the answers will usually be in terms of tons/acre (or tonnes/hectare). What about all of us suburbanites growing grape vines in pots? We trim the roots and are left with vines that can produce less than if they were planted in the ground. So even if we could convert tons/acre into pounds/pot, we would still be over cropping. It looks like we’re on our own.

I can’t explain this glaring and puzzling oversight, but here’s how I deal with it. I control the hight of the vine for my convenience; I need to be able to reach the top easily for pruning, harvesting, applying bird netting, and so forth. I look for opportunities to create a spur, and prune each spur so that it’s long enough to push at least one fruitful bud. I suppose I’m relying on the vine to push the right amount of foliage for it’s root system, and managing the buds and clusters so that all the grapes ripen well. I thin to insure that there is only one cluster and at least fourteen leaves per shoot. If I find that some shoots don’t push out enough leaves, I’ll aim for two shoots per cluster next season. To do that I would thin one shoot normally, then remove all clusters from a neighboring shoot. The goal is to make sure that there are enough sugar-producing leaves to ripen all the grapes.

I’m making some changes for my Swenson Red, as I mentioned in this post. As I learn more, my approach will evolve.

Pinot Noir: What’s in a name?

Pinot Noir Ripening on September 19, 2007

Pinot Noir was one of the first grape vines I acquired. My research indicated that it was the only traditional red wine grape that would ripen in my neck of the woods, and I was right about that. What I missed was how many different kinds of Pinot Noir there are. It’s a very old grape that growers have been propagating for 1000’s of years (really!) by rooting cuttings. Each cutting ought to be, and almost always is, identical to the mother plant because there is no pollination or any other exchange of genetic material involved. Over those 1000’s of years, little variations popped up. Pinot Gris and Pinot Blanc, for example, have the same DNA (there must be some difference, but my understanding is that genetic testing can’t tell them apart) as Pinot Noir but are legally different varieties. Many other different kinds of Pinot are legally “Pinot Noir”; these are clones.

One clone that growers here in the Puget Sound are getting excited about is called Pinot Precoce (Fruhburgunder in Germany). It ripens up to three weeks earlier than other clones of Pinot Noir, and that’s huge in a cool climate like ours. I said “other clones,” and one thing local growers are wrestling with is weather they can call wine made from Pinot Precoce “Pinot Noir”. If it’s a clone, then yes, if it’s a “sport” or offshoot, then no. The answer to that question may have as much to do with the commercial success of this … clone, sport, whatever as how good the wine is.

I did some digging and found out that my Pinot Noir is clone ESP374. Never heard of it? It is also called FPS100. Oh never mind – it’s not a very popular clone. I’m hoping to move, in the near future, to a place with enough land to plant a small vineyard in the ground. Maybe then I’ll try this Pinot Precoce or whatever the current fancy might be by then.

Swenson Red Needs To Be Cane Pruned

In yesterday’s article about pruning, I mentioned that I pruned to spurs on a vertical cordon. That means the trunk is permanent and I maintain short branches of one year old wood, called spurs, that come out of the trunk. If those one year old branches were long, a dozen buds or more, they would be called canes. Canes would make repotting the vines more tedious and would require more support. That’s why I decided to spur prune.

It turns out that some varietals need to be pruned to canes in order to bear fruit. In those varietals, the buds closest to the trunk are not fruitful. If you spur prune them, you’ll get lovely foliage but no grapes. That’s what happened to my Swenson Red last year, and may happen again this year. I pruned in March, and had a vague idea that I should be less aggressive, but I didn’t really know what went wrong or how to fix it. When I prune for next season, I’ll know what to do, but this season, I’ve got longish spurs that aren’t quite canes.

Pruning My Grape Vines

Grape vines need annual pruning. Because I grow mine in pots, they also need annual root trimming. I’m still getting the hang of this, but my current thinking is to train my grape vines to a vertical cordon. The single permanent trunk with fruiting spurs (short one year old branches) will be compact and easy to remove for root trimming. It won’t need much more than a stake for support either.

Siegerrebe grape vine after pruning and before root trimming on March 28, 2007

The photo above shows a Siegerrebe grape vine after I pruned it and just before root trimming. That was on March 28, 2007. You can see two spurs, well they maybe a bit large for spurs, and I’m expecting a small crop on them this year.

Trimming the roots of a Siegerrebe grape vine on March 28, 2007

I’m trimming the roots in the above photo. My goal is to keep the whole root structure small enough to fit in the pot. I’m also trying to keep the root mass as productive as possible. The roots of any plant, including grape vines, are mostly structural. It’s only the fine tip that is actually collecting water and nutrients for the plant. When I trim the roots then, I’m looking to get rid of the big woody roots and leave a mass of small feeder roots.

Siegerrebe grape vine on March 28, 2007 after pruning and root trim

This is what it looks like when all is said and done. Now it’s ready to go back in the pot and make me some grapes!