Vineyard Topic: Dormancy and Pruning

Right now, wines are supposto be in dormancy. But I get the sneaking suspicion that given our occasional warm periods, that vines in California do NOT get the dormancy that those in Atlantic climates do.

How does dormancy effect wine quality?

What can be done to ensure better dormancy (if anything?)

Does pruning have any effect on dormancy?

Cellar rats?

We need to get Peter back here because IIRC, he was mentioning before a reason to prune early.

He’s traveling, or on vacation or something - I recall something of that ilk on his facebook

Hi Roy- I threw a response at you on the other board, just in time for the whole crew to jet.

I’m no plant biologist, but I know a couple of them.

Dormancy is a plant response to conditions. Preservation of life and all. It is essential in some plants for fruit production, but AFAIK, not in grapes. In fact, in many parts of the world grapevines, even vinifera, never go dormant. In places like Thailand, for example. Whether or not they can make great wine from it is certainly debatable, but is also a chicken and egg argument due to their climate.

During dormancy, the phloem is inactive and there’s no appreciable transfer of carbs around the plant. When we talk about sap running, the concern is that this means the vasculature is still working. The concern there is that this takes energy…energy that is better preserved.

In grapevines, there are many contributing factors to the end of dormancy, including sunlight incidence and day length, rainfall, and temperature. Probably the biggest determinant would be soil temperature, which, when raised a bit sparks a root flush and we’re off to the races before you know it. If we get a warm rain now, for example, that may spark some budbreak. As you probably know, soil temperature is very, very stable, so it takes some extreme conditions to make significant changes.

How does dormancy effect wine quality?

AFAIK, it doesn’t, except that the end (and beginning) of dormancy determine the growing season. Bud differentiation and flower cluster production occur in the Spring of the previous year, so I don’t think dormancy affects potential yield much.

What can be done to ensure better dormancy (if anything?)

Nothing I know of. I don’t think “better” is the key; “longer” might be for us here, but other places are twiddling their thumbs praying for budbreak because every day the start is delayed is another day of risk for rain at the end of the season.

Does pruning have any effect on dormancy?

There is certainly an effect on the vine when pruning, much as we respond to cuts. AFAIK, pruning will prolong dormancy. In other crops, there are only ways to hasten dormancy…Dormex is a spray often used in cherries, for example, that tightens up bloom and reduces ripeness variability. AFAIK, there isn’t a way to prolong dormancy.

So, all in all, the biggest concern with a shortened dormancy will be that budbreak in February puts us at risk for more frosting, potentially bad bloom weather and the lion’s share of the ripening occurring in the summer. These are symptoms of short dormancy, though, and not necessarily related to dormancy itself.

When its projected to be dry I irrigate in order to increase the mass of the soil. It takes more heat energy to shift the temperature of a high mass soil upwards. I also leave the cover crop high, which acts as a soil insulator. It keeps the sun from striking the mineral soil and conducting heat thereby slowing down soil warming.

When the heat hit I started pruning from shallowest (fastest warming) soils first to use the pruning wound as a dampener. Not pulling the brush from the trellisses, just cutting and pruning to wound the vines and slow 'em down.

I also burn little straw effigies of gophers on the altar to Saturn.

ROFLMAO!!

[laughingneqw.gif]

Ah…well then you farm Biodynamic. [bye2.gif]

Todd, bummer that you missed the bbq gophers and roasted penguins at the falltacular. Did the gophers with a 45 minute sage brine. Exquisite little morsels! I’ve been asked to prepare them at a little tailgate party with Andy Peay and Morgan Clendenen at HdR. (HdR is my favorite 2 day party!!!)

Were they served on a stick? That’s the best. Easy to dip in Sweet Baby Ray’s BBQ Sauce (The Sauce is the Boss)

Nate, Going from rusty memory here, but I think its not as clear cut as cell primordia differentiation in the prior year. There is another regulatory mechanism during dormancy that somehow influences that potential based on carbohydrate reserves.

Frosting + water shortage = ugly! I’m so glad to see the rain.

Nate, Going from rusty memory here, but I think its not as clear cut as cell primordia differentiation in the prior year. There is another regulatory mechanism during dormancy that somehow influences that potential based on carbohydrate reserves.

Probably. I’m rusty as well and there are certainly a lot more complex things going on. Hormones and chemical signals and all. Auxins and ABA and cytokinins, oh my!!

Like I said, I’m no plant biologist or physiologist. I’m not even a viticulturist. I know just enough to spout off on the internet.

I do think that dormancy affects the quality of a vintage based more on when it begins and ends than any other parameters.

Getting some pretty good run up here in Foss Valley at the moment (and it’s f-ing cold). A welcome sight and the forecast looks promising for next week. We’ll see how much it drops on us.

Won’t too many of these also raise soil temperature?

This is good stuff. I put a similar thread on the “other” board to see if I can expand this topic.

I don’t think gopher effigies are popular on that board.