In the immortal words of Jim Morrison, This is the End (of the Glog).  It has been a fun, educational tool for me to communicate with growers and I hope that you found it useful.  This is the last entry, but it will remain up for reading — at least for awhile.  I will start a new blog sometime after I start at Mississippi State University and it will be on  Some other capstone items I wish to say:

1. Please continue to support OSU’s viticulture and enology efforts.  Just because I am leaving does not mean the program just goes away.  And if you would like to see my position refilled (that is not guaranteed!), I suggest developing a strategic plan to make this happen.  Contact the appropriate people (department heads, deans, provost, president, legislators, anyone with influence — and money), find a way to provide some funding to support research and extension efforts and do it on an annual basis, and come up with a plan of attack that may include having discussing with folks in the pecan industry.  It is unlikely that the position will be refilled solely as a grape position, but as a joint position with pecans is possible.  A plan of action may look like this: rally support for filling the position within the industry by drafting a position paper on why it needs to be filled as soon as possible, develop a plan for funding assistance to do the work you need done through research and extension, develop strong relationships with the OSU horticulture dept head and OSU division of agriculture dean.  If they don’t know you exist, then they won’t care.  How many times since 2005 (when I started) has anyone in the industry interacted with the dean?  I don’t know the answer to that, but if it is 0 or a very few times then that does not bode well.  A plan of action must include items like “why the position is important to the industry”, “what does the industry bring to the table in order for the university to invest in the position”, “how is the industry growing and what are future projections such that a continuing presence is needed?”.  Think about resources that might be available for an extension specialist to use (in-kind services, etc.).  In essence Why does the grape and wine industry of Oklahoma need this position to be filled and what is the Oklahoma grape and wine industry prepared to do about it?

2. Contribute your voice to an industry organization and keep abreast of what is happening in the industry now.

3. Don’t forget to read my last issue of Le Vigneron (to be published sometime early October).  It will include some photos of our vineyard, data and interpretation of the Perkins vineyard since 2002, and some other goodies.  At this point I don’t know if it will be the last one or not, but it will be a “blow-out” issue.  If you are not on the mailing list you can always find it online here (

4. Growers and wineries need to stick together and display a unified front to legislators.  Find a way past the differences and work together.  To be honest, other states have really gotten their acts together and formed cohesive state organizations that get a lot done.  It might be a good idea to talk with leaders from other states that are on a similar scale to Oklahoma  (like Kansas, Minnesota, Iowa, Nebraska, etc. to find out what they are doing that is successful).

5. Be leery, but not dismissive, of vinifera grapes.  Well, maybe dismissive in many parts of northern Oklahoma.  Vinifera grapes can grow in Oklahoma, but we are concerned not only with growth.  We are also concerned with productivity, survival, disease resistance, and fruit quality.  Through my six years here I have come to these conclusions: Vinifera grapes are high-risk and should not be a first choice north of I-40.  South of I-40 on excellent sites they can be considered but not all varieties work.  Always use a rootstock, preferably a low vigor rootstock like 101-14.  Economics must be a prominent thought in variety choice.  What price per ton can be obtained?  How much does it cost to maintain per acre per year?

6. Open your mind to hybrid grapes.  There are many good varieties out there.  The only way to learn about them is to taste the wine and view the vine growth.  There are opportunities to do this within Oklahoma as well as in surrounding states.

7. If you have not done so already, please complete this survey:

8. Attend conferences such as ASEV, Unified Symposium, Midwest Grape and Wine Conference, etc.  The national perspective you get from these types of venues are invaluable.

9. Stay positive.  Oklahoma is a difficult place to grow grapes, but it can be done (with proper variety selection, site selection, management, and education).  Setbacks will happen, but Oklahoma has a terroir different from anywhere else, so it is exciting to be able to taste that through the grapes.  Taste Native Oklahoma is something to strive for.  Will it be possible to have an industry built entirely on Oklahoma grapes?  I don’t know, but at this point it is unlikely and impossible.  However, with a positive attitude anything is possible.

10. Not sure what else to say, but I wanted to have 10 items here.  So, as Bill S. Preston, Esq. once said, “Be excellent to each other.”


Yes, the end is coming soon for this blog.  When is the last day?  I’m not entirely sure, but probably somewhere around September 22.  The reason?  Well, for one thing I am leaving on the 23rd to give a talk at a conference in Hawaii.  Secondly, if you have not heard by now, I am leaving OSU on October 14.  I have been offered, and accepted, another position similar to this one at Mississippi State University.  I start there on November 1.  I will still be in the grape world — I will continue to be the Project Leader of and I will start a new blog that can be read from that website.  It will no longer be Oklahoma specific, but I will touch on grape growing in the Deep South as well as other broader topics of interest.  There are many loose ends concerning how things will continue here at OSU, but meetings will be held to discuss those things and we hope to have a plan in place before my departure.  I have really enjoyed doing this blog and I hope you will continue to follow me when I move over to my new blog.

Two recent studies were done in the Mississippi river basin region and another location to see if Glyphosate was detectable in water and air samples.  See below for a short summary of what they found:

Glyphosate (tradename Roundup), a Herbicide – Occurrence and Fate in the Mississippi River Basin – In an article published in the journal “Environmental Toxicology and Chemistry”, researchers from the U.S. Geological Survey (USGS) and the University of Minnesota in Minneapolis examined “… ambient levels of glyphosate, the most widely used herbicide in the United States, and its major degradation product, aminomethylphosphonic acid (AMPA), in air and rain … during two growing seasons in agricultural areas in Mississippi and Iowa [and found that] the frequency of glyphosate detection ranged from 60 to 100% in both air and rain [with] concentrations of glyphosate [that] ranged from less than 0.01 to 9.1 ng/m3 and from less than 0.1 to 2.5 micrograms/L in air and rain samples, respectively …” – The study estimates that “… an average of 97% of the glyphosate in the air is removed by a weekly rainfall greater than or equal to 30 mm …” – In a separate article published in the journal “Pest Management Science”, researchers from the USGS and the National School for Water and Environmental Engineering in Strasbourg, France found that “… glyphosate and AMPA were frequently detected in the surface waters of four agricultural basins … and the load, as a percentage of use, ranged from 0.009 to 0.86% and could be related to three general characteristics: source strength, rainfall runoff and flow route …” – The study concludes that “… the watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff and a flow route that does not include transport through the soil …”

Granted, most of the hard, nitty-gritty work is done by enterprising winery and vineyard owners.  These are the folks who point the industry in a positive direction and I have been happy to see that start to happen again in the past year.  However, the industry can only do so much — you need help.  You need help in areas like education.  OSU has been providing the Grape Management Short Course for a decade.  Redlands CC provides courses.  These are great at helping a grower/vintner get started in the industry; however, what happens when new problems are encountered?  New challenges that were unforeseen?  This is where research and extension fills the bill.  The education component without the benefit of research and extension can only go so far.  If we don’t do research in Oklahoma on grape growing and wine making, then essentially you are learning how to grow grapes from Missouri, Texas, or California — the local knowledge is missing.  Luckily in the past decade we have done research trials at our Perkins station, but also in Buffalo, Burns Flat, Stillwater, Bixby, and Oklahoma City.  We have learned a lot and I have tried to pass on some of those results to you through my extension appointment, but we still have so much to learn.  I encourage the industry to develop a strong, long-term plan that focuses on how to help fund viticulture and enology efforts.  I am here to tell you right now that if the industry does not get involved those efforts will never reach the level that is needed.  Some states have figured this out and have started to make those contingency plans for when the state (university) is no longer able, or willing, to fund to the level needed.  Read this article out of Washington and Oregon in today’s Wines and Vines:

I also encourage you to take a look at some of the resources OSU has developed and evaluate them for yourself.  How useful are they?  How much do you value them?  How much more is needed?  Below are just a few examples:

OSU Grape Newsletter:

OSU Grape Short Course:

OSU Viticulture Research:

OSU Viticulture Handbook:

OSU Enterprise Budgets (examples):

OSU Black Rot Advisor:

OSU Grapevine Disease Testing Service:

Midwest Small Fruit and Grape Spray Guide:

OSU Grape Insect and Disease Control:


Those are just a few of our offerings at OSU — it is really up to you to decide how much farther we can go together.

My colleague at Penn State University, Mark Chien, sends out an email newsletter that contains all kinds of great info throughout the season.  Although focused on Pennsylvania and the mid-Atlantic region, there is application of many of his writings to the rest of the country.  In his latest issue he reviewed a new book by John Gladstones called “Wine, Terroir, and Climate Change”.  I have not read this book yet, but Mark gives a good review of some of the key components.  Gladstones wrote a previous volume entitled “Viticulture and Environment” — a classic in the field.

To get to flavor and pigment development, Mark summarized this from Gladstones latest book:

“Flavor and pigment development respond most readily to moderate temperatures, similar to or slightly below those necessary for optimal growth, 14C at the lower threshold and 26C at the upper with 20C as the sweet spot in-between. It might be said that this represents the Holy Grail for environmental conditions in the stretch run, the goal being to ripen the fruit as quickly and efficiently as possible with optimal flavor and aromatics and balanced acid and alcohol. These are a lot of variables to align and every wine grower knows it is almost impossible to get all of these development curves to intersect at an ideal date on the calendar. Gladstones hedges his comments a bit by saying, “a range of optimum temperatures can be discerned, depending on grape variety and suggested ripening period optima for other climatic elements. His Table 3.1 on page 36 offers the suggested optimal climate averages for the final 30 days for a variety of wine styles.

As they have in California, I conclude from this that wine growers in warmer areas, mostly below the Mason-Dixon line, need to look to the hills to achieve the most effective diurnal effect for wine quality. As cooling occurs with higher latitude and elevation, warmth may be sought to bring the diurnal range to optimal range, for example, in the “banana belt” on the south and east shore of Seneca Lake. Gladstones formulates the same adage that grapes favor a cool site in a warm region and vice versa.”

If you need the temperature translation, 14C = 57F; 26C = 79F; and 20C = 68F.  As I said before, I don’t have the book yet and have not seen Table 3.1 that Mark references.  But also notice that Gladstones says that the temperature range differs among varieties.  I can tell you right now that we are not averaging these temperatures this year.  But other years, we can come close or be within the range.  For example, in 2010 at Perkins, if we harvested variety X on August 30, the average temperature was 29C = 83F.  Not too different.  Other years like 2009 and 2008 we are right in the higher end of that range.  If we had varieties that could be harvested at the end of September, then we are right in the optimal range.  There are a couple ways to get this done — one, choose varieties with later harvest dates (with this usually comes the added bonus of later budbreak).  Two, vine manipulation to delay harvest.  Work is currently being done in California at Fresno State by Sangliang Gu.  He has studies going that look at vine hedging and pruning at different times in the season to delay harvest, a technique called “Crop Forcing”.  He is finding some promising preliminary results in terms of berry chemical properties being enhanced, but also finding there is variation among varieties — some respond well and others do not.  This is ongoing work.  I started a similar study at Perkins in 2009 on ‘Neptune’, but only did one pruning time.  Since I did it early (May 1), the vines were able to catch up and harvest was not delayed much beyond a few days to a week.  Later pruning would likely push the harvest back later.  This would be a great area of study to pursue since it has the potential to significantly increase fruit quality.  The other part of this though is that sugar content may be sacrificed some, but the real issue is “should we be so focused on sugar content at the expense of pH, TA, malic and tartaric acid, K, etc.?”  Chaptalization is something we need to strongly consider as a tool in the winemaking arsenal.  As Mark states in his newsletter:

“As a wine grower, I tend not to fret over alcohol too much since careful chapitalization of wines is one of the least intrusive cellar interventions that can bring a wine into alcoholic balance, as has been done frequently in European wine regions prior to the recent effects of climate change. So as much as we tend to focus on brix as a parameter of ripeness, its importance is only that of a common indicator for other less well-defined criteria of fruit maturity (e.g. flavor, tannin, etc.).”

Something to think about as we move forward into the winemaking season.

There is less than one month until the survey on our OSU Viticulture and Enology Website is over and we need to compile the results.  If you would like to fill out the survey please copy and past the address below into you browser and fill it out.  A few folks have had some difficulty — this may be due to your firewall settings or the browser itself.  If you experience any problems try it in multiple browsers (Internet Explorer, Netscape Navigator, Google Chrome, Mozilla Firefox, etc.).

Currently, we have about 60 responses, we would like to get 100.  Remember, as an added bonus for participating, if you add your email address at the bottom of the survey you will be entered to win a prize of three viticulture related books: Handbook of Oklahoma Vineyard Establishment and Management, Pocket Guide to Oklahoma Grape Diseases, Insects, and Other Disorders, and the 2011 Midwest Grape and Small Fruit Spray Guide.  The deadline is August 31.  Please help us improve our website.  You can also go to our website and find the link to the survey there:




High temperatures affect different grape cultivars differently.  It depends on their species background and genetic origin.  Generally we think of Vitis vinifera grapes as being heat tolerant, but there is variation within the species.  Temperatures up to 95 F have been shown to be acceptable for several cultivars.  But what about 110 F?  We are having a summer akin to that of the Xinjiang Province in Northwest China, where maximum summer temperatures approach 118 F, most days are over 95 F and the average July temperature is 91 F.  Few studies have been done to really understand the effects of high temperatures, especially high nighttime temperatures on grapes.  Some of the  effects that occur due to excessive heat during the time of fruit growth and ripening include:

-Reduced number of berries per cluster due to high root temperatures (seen in Cabernet Sauvignon).  The soil temperature recorded so far in August at Perkins has averaged 96 F (bare soil), with readings as high as 106 F.

-Earlier fruit maturation (short term conditions).

-Delayed fruit maturation and a reduction in fruit quality (excessive and long term conditions).

-Decline in total TA and increased pH through loss of malic acid.

-Increased mon0 and di-basic salts of tartaric acid.

-Reduced color development (anthocyanins) in red berries.

-Reduction in gas exchange capacity (although this is influenced by vapor pressure deficit).

-Potential elimination or reduction of virus with long term exposure (>30 days).

-Reduction of leaf starch content.

-Reallocation of photosynthates, going to shoot tips at expense of roots, trunks, and clusters.

-Increase in sucrose concentrations in all vine organs.

-Decreased glucose and fructose concentrations in fruit (observed in Chardonnay).

I obtained this info from the  “Handbook of Environmental Physiology of Fruit Crops, volume I Temperate Crops”.  The grape chapter was written by Larry Williams, Nick Dokoozlian, and Robert Wample.

One aspect not discussed in detail was the interaction of water availability and heat stress.  On March 17, 2010 I had a blog entry entitled Rootstocks and Heat Tolerance that looked at different rootstocks with Chardonnay as the scion cultivar.  On a day with 113 F at Perkins, the canopy temperature did not exceed the ambient air temperature.  In essence, the vines were able to keep themselves cooler by transpiring because they were being irrigated.  Even so, it doesn’t mean some of the effects listed above were not occurring as well (although the 2009 heat event was short-lived compared to this one).  So, my recommendation is to keep watering the vines — it is TOO HOT.  Not only can fruit quality be negatively impacted because the vine cannot properly allocate resources (remember during this time of the year fruit development is driven by a healthy canopy and photosynthates are translocated through phloem tissue) due to loss of leaves or heat/drought damaged leaves, but overall vine health can be impacted as well.  Root system size could be reduced because of a lack of vine and soil resources to draw upon.  An earlier than normal loss of leaf area can result in decreased winter hardiness as well.  I hope we don’t hit -20 F again this coming winter, but after living here awhile I would not bet against it.  If you have already harvested, put water to the vines.  If you have not yet harvested, I would water as well, but perhaps not quite the amount as after harvest.  This is a difficult year and vine stress is a real negative going into the fall and winter, especially if they were previously damaged from the February freeze event.  Luckily for us, grapevines are extremely resilient, but they are not indestructible.


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