Wine Blog

[Toliver]

So is early heat a bad thing when it comes to growing grapes? Does it change the way the grapes are tended and eventually harvested? Does it effect the eventual sweetness (or lack of it)? This is quite interesting. Thanks for posting the blog!

[Carolyn Tillie]

Carolyn, this continues to be a fascinating and valuable blog. By the way I love your new avatar.

Thank YOU!

[Carolyn Tillie]

So is early heat a bad thing when it comes to growing grapes?  Does it change the way the grapes are tended and eventually harvested?  Does it effect the eventual sweetness (or lack of it)?  This is quite interesting.  Thanks for posting the blog!

It is an interesting thing... I PM'd Bombdog about it to get some clarification. What can happen is called shatter. I learned about it for the first time last year -- Almost half of Gundlach Bundschu's Merlot was hit by shatter due to early heat. Here's what Bombdog told me:

Wow, great question. I had to go back to Winkler's General Vit again. Honestly, we didn't study shatter AT ALL as a result from early season heat. With that in mind, and the fact the Winkler gives the subject scant mention (2 paragraphs) I'll try to give you a good answer.

In wine grape growing, shatter is "the setting of shot berries," or small berries. Winkler says that certain varieties (the ones he mentions are obscure at best) are subject to the condition and it is reduced best by the type of pruning (cane) which provides greater development of the leaves before flower blooming. He goes on to say that when shatter is a result of zinc deficiency the pruning described above helps, along with zinc application.

Whew!

Okay, from that I deduce that the abnormal few days of heat we are having at the moment are not a big problem. Mainly because no one I know is growing Muscat of Alexandria or Red Malaga (as mentioned by Winkler). If you had a rather unhealthy vine, with small leaves, and an extended heat wave (high 90's) you might get some problems.

Winemega.com mentions that Merlot and Malbec are particularly suseptible to shatter from frost, rain, or excessive heat. Several other web sites describe shatter mostly as a loss of berries or flowers as a result of late rains.

I'm taking a shot here, but unless the excessive heat really drags out (a week or more) AND the clusters are not adequately protected by leaves, there is not a great concern over shatter from the heat.

I remember specifically the first year I moved to Napa, we had a heavy thunderstorm with hail in May. In August, while doing berry sampling, we noted alot of shot berries in the clusters as a result of that storm in May.

I hope that helps some. Personally, the risk of frost a couple of weeks ago, and the threat of those thunderstorms worried me alot more than the heat. I don't think most growers are going to be overly concerned about the heat right now. If it were to continue, like I said, then maybe they'd be worried.

I would also think the winemakers would be liking the little bit of extra heat to help the vines 'push' the vine growth a bit now.

So, sitting in the office next to me is Gabriel, having lunch with a guy that sells some of our vines to us. I spoke with them about this early heat. The shatter problem of last year was almost exlusively a Merlot issue. This guy said that shatter is the result of two things: Weather and Nitrogen. Right now, the early heat is not a problem for us, but can be for those growing Merlot who are using too much nitrogen.

We are fine and Gabriel is loving this weather, projecting that we may actually be harvesting as much as three or four weeks earlier this year. He is also hoping there won't be any more nights of frost. He has only had three or four this year total (last year, there were almost 20 days of frost).

Generally, this early heat is a good thing.

Convoluted answer, but I hope it helps...

Edited April 28, 2004 by Carolyn Tillie (log)

[Toliver]

Generally, this early heat is a good thing.

Convoluted answer, but I hope it helps...

That's a great answer! Thank you and thank Bombdog for all of the info. It's very enlightening.

[SethG]

It's true, this blog is great. Very educational.

My real reason for posting: how come I still see Carolyn's old avatar?

[Bombdog]

Does it change the way the grapes are tended and eventually harvested? Does it effect the eventual sweetness (or lack of it)? This is quite interesting.

At this stage in the growing process, heat really isn't a direct factor in the sweetness of the fruit. Indirectly, of course, it is for alot of the reasons Carrie and I said above; too much for an extended time can cause some problems and certainly too little or complete lack of has obvious consequences.

Where heat really becomes a factor is in the last stages before harvest. Typically, in late September and early October, the days are growing shorter and are a bit cooler. This is the point where winemakers are in the vineyard doing berry sampling daily. It's not unusual for us to have a small heat wave in October; a week or so of really warm weather. When that happens you will frequently hear winemakers wax poetically about the effects on the fruit. That heat period will give the grapes that extra push, ripening a bit more, raising the sugar level a bit and giving the fruit some more complexity in flavor.

We'll get into that part more later in the season, after verasion.

Just to add a bit to the nitrogen explanation. In a normal vineyard, one which doesn't require soil additions, nitrogen is really the only fertilizer used. Nitrogen helps the vine produce green growth, which is really desired at this point. Normally, there are a couple of times during the year when nitrogen applications are called for, primarily after harvest, and early season, after bud break.

Most vineyards are established today with a drip irrigation system. This allows a liquid nitrogen to be injected into the irrigation. If a vineyard had received too much of that nitrogen, post bud break, coupled with an extended heat wave, and the varietal being grown is susceptible to shatter, the results can be what GunBun experienced last year.

As far as our weather. We were supposed to have only 2 or 3 days of the high 90's that we had. Forecasts for the south part of the county, where I live, were for 81 today as a high. I just checked the recording thermostat (at 4 pm) and see that it was 91 here today. We were SUPPOSED to have a bit of a cooling trend for the next few days followed by some more days in the mid 90's. Frankly, I'm not too confident lately with our weather guessers.

It's not going to have any devasting effects, at this point. However, what everyone wants now is to have consisently warm, comfortable days. But, don't we all?

[Toliver]

We're supposed to have the same sort of weather pattern here (Southern Central California) so the weather prognosticators seem to be in agreement (or are working off the same forecast ). Cooling a little than getting hot again.

The bit about introducing the nitrogen in the irrigation system makes perfect sense. I've seen similar home-systems used in the same manner.

Thanks for taking the time to post this information! This is a great blog.

[Bombdog]

You're very welcome. I hope everyone is enjoying it as much as I am posting it.

[Carolyn Tillie]

It's true, this blog is great. Very educational.

My real reason for posting: how come I still see Carolyn's old avatar?

Blowmogawry told me to clear my cache... It seemed to work (finally!)

[Carolyn Tillie]

You're very welcome. I hope everyone is enjoying it as much as I am posting it.

And I couldn't be happier having a partner in crime that is a lot more coherent in these matters! Damn, Bombdog, I'm gonna owe you a bottle or two of Ladera wine before all this is done! I hope you'll bring Lynn up to see the winery some day soon...

[Bombdog]

I hope you'll bring Lynn up to see the winery some day soon...

Oh, you can COUNT on it!

[hathor]

You're very welcome. I hope everyone is enjoying it as much as I am posting it.

Yes, I am enjoying it immensely! Many thanks for the time and effort that you are both giving this. Its particularly engaging, as we are following along with the acutal seaon. Regards!

[Carolyn Tillie]

It may be hard to tell at this point how much growth is going on. We will see a lot of growth in the arms and leaves before the grapes start to expand. BTW, it is still very warm here!

[Carolyn Tillie]

It's getting bigger - and there has been no further frost this year. Unlikely that there will be any at this point.

And the grapes are growing in size as well!

[jmcnally]

Just discovered this! Thanks Carolyn! I work for a wine importer here in Toronto and though I have visited Napa and Sonoma before, I've never had this up close and personal look at the vine's life cycle. Keep up the great work.

[hathor]

Thanks for the pictures! As usual, I'm curious...what type of daily maintainence is required in the vineyard at this point in the growth cycle? Is there any culling of fruit at this point?

[Carolyn Tillie]

Thanks for the pictures!  As usual, I'm curious...what type of daily maintainence is required in the vineyard at this point in the growth cycle? Is there any culling of fruit at this point?

In about two or three weeks, we will be sucoring - (pulling shoots/thinning leaves). Then, in about six weeks, we will start dropping fruit.

Some of the daily maintenance includes spraying Round-Up for weeds and occasional tractoring up and down the aisles - we want the earth to work on the grapes, not on the ground cover and weeds that develop.

Edited to add - if you go back and look back, just when the shoots were starting, there is considerable grass on the ground behind the vines. In the pictures now, the ground is churned up...

Edited May 12, 2004 by Carolyn Tillie (log)

[Toliver]

I'm assuming somewhere along their development that the grapes will become a sought-after food source by birds, squirrels, bees, etc. Is this much of a concern? And how is it dealt with?

[LindaJ]

At the house we just bought in December, we have a pergola in the back that is covered with grapes (what variety I have no idea). We're in the Mid-Atlantic so I'm not expecting vinifera, but golly this thread is really interesting from an amateur gardener point of view. Can you explain a little bit more about the sucoring process? Maybe I'm ahead of myself, but it will be really educational.

[Bombdog]

I'm assuming somewhere along their development that the grapes will become a sought-after food source by birds, squirrels, bees, etc. Is this much of a concern? And how is it dealt with?

Toliver, the fruit is indeed a tasty target for birds, but not until verasion occurs (the point where the berries begin to ripen). At that point vineyard managers will do anyone of several different types of things.

The most prevelant, and most say effective, is the use of netting.

Others will use strips of bright mylar and still others might opt for percussion devices (shotgun sounds).

When I was in school our professor said that the mylar was simply a way of helping the birds find the berries easier.

Research at UC Davis has shown that although effective for a short time, birds soon become accustomed to the percusion devices and simply ignore them.

However, since most birds will not venture past a couple hundred yards from the trees they use for cover, only those vineyard rows within that distance are normally netted.

Squirrels are not normally considered a problem in the vineyard. Bees can be a problem and there is really nothing done to aleviate them. For the most part, bees don't become a real issue and don't really disturb the crop until near harvest when the brix is very high.

[Carolyn Tillie]

I asked Gabriel about our pest-aversion processes before I left this evening. When a vineyard is first planted, you can often see new cuttings put into the ground, surrounded by milk cartons and other protective encasings. (I'll shoot a picture of this next week, since we are planting new vineyards right now). Those encasings protect the plants from rabbits and squirrels and other animals that are low to the ground.

Once the vines are higher up, the birds are usually the main concern. As Bombdog indicated, some vineyards will use netting or mylar strips -- I'll shoot some pictures of those when the time comes from other vineyards. It can be quite beautiful to see an entire field with those shimmering strips, fluttering in the breeze.

In talking with Gabriel and the vineyard crew at GunBun, the real loss of fruit to birds is minimal for red grapes (too bitter). When Ladera was Chateau Woltner and planted entirely with Chardonnay grapes, Gabriel said the damage was pretty extensive. Now that we have budded over to an entirely red grape crop, our damage is very little.

Like Bombdog said, it is vineyards that are closer to trees that have more to worry about. At Gundlach Bundshu, it is only those grapes that are at the edge of the property and near trees that warrant the mylar strips. Since most of the vineyards are in more open space, and there is no escape flight path for the birds, those are more protected. Lastly, the few vineyards that use netting do so at great expense. For many wineries, it simply is not cost-effective to net the entire property, when as little as 5% might be lost to birds.

[winesonoma]

Deer can also be a problem. However venison fed on grapes is delicious.

[Toliver]

Bombdog and Carolyn,

Thanks for the info. That makes perfect sense. I never imagined growing red grapes as a form of pest control!

Another question I have is:

Is cross-pollination a factor when growing grapes? The fruit (grapes) don't seem to come from flowers as is the case with most fruits. Or did I miss this step in the growing process?

[Bombdog]

Bombdog and Carolyn,

Thanks for the info. That makes perfect sense. I never imagined growing red grapes as a form of pest control!

Another question I have is:

Is cross-pollination a factor when growing grapes? The fruit (grapes) don't seem to come from flowers as is the case with most fruits. Or did I miss this step in the growing process?

Actually, the clusters do flower before becoming berries. I don't think Carrie posted a picture that actually showed that step yet.

I don't know if I have this right yet, as it's my first attempt to post a picture, but here is a cluster from a table grape vine in my back yard. As you can see, there are a few flower remnants and the beginning of the berries. I think you can actually see a cap or two also, where the remnant of the flower is still sticking to the top of the new berry.

As far as pollination goes, there seems to be several theories with some support to wind and insect polination in vinifera. However, studies at UC Davis have led to a dominant belief that wine grapes are self pollinating.

[Toliver]

As far as pollination goes, there seems to be several theories with some support to wind and insect polination in vinifera.  However, studies at UC Davis have led to a dominant belief that  wine grapes are self pollinating.

Thanks for posting the picture. I figured there had to be flowers somewhere. That makes perfect sense. It's just that you don't really think of grapevines having flowers....just fruit.

In terms of cross-pollination, is it a problem if you're growing one kind of grape and the neighboring vineyard is growing something different?

For example, with chile peppers you're supposed to yank the pepper plant at the end of every season and start over with original seed stock since the possibility of cross-pollination changes the plant's fruit over time. Meaning you may start out with true Thai chile peppers but if you keep the same plant the following year, the fruit it bears may not be as "true" as it was the year before. I hope that makes sense.

Of course, if the grapes are self-pollinating then this would not be a concern at all.