Sunday, October 16, 2011

2011 Season Review

We harvested the grapes on October 6th this year.  That gave us 158 frost free days and about 934 degree days growing.  The season started with good winter survival of the vines/buds with the coldest winter temperature being -22. (see link to climate data for details).  Last spring frost was May 2nd and fall frost was October 8th.
May was cool, below normal with the usual abundant rainfall.  Bud break for most varieties was approximately May 18/19th.  All varieties were given a 8-8-8 fertilizer treatment and a micro-nutrient treatment (Scotts Micro-Max).  Practice double pruning to reduce potential loss to late spring frost.

June was fairly close to normal temperature, except the last 10 days of the month and first week into July was below normal and delayed flowering a few days.  Average rainfall.

July was cool and continued the cool spring trend.  Flowering was first week in July for all varieties except Ravat 34.  Ravat was about 4-5 days behind the other varieties which is unusual as Ravat typically flowers the same time (+/- a day) as the other varieties. (This should have been my first clue that this variety was over cropped).  Rain was moderate to low and the last rain in July was on the 23rd.  This was the start of the drought that lasted until mid September.

August was normal for heat, hot days on average, no rain the entire month.  By August 23rd the vines were looking fine, Leon Millot was well filled out as were most other varieties, however the berry development of Ravat 34 was delayed.  The Lucy Kuhlman and Colmar Precoce Noir were just starting to show some colour on the 23rd.

September was above normal for heat (monthly average of 15.3 degrees c) and the drought continued until September 17th (8 full weeks without any rain).  As of the 10th most varieties were showing moderate to high water stress, Ravat was showing severe water stress and was given some water.  Most varieties were colouring well, but the berries are noticeably small compared to normal especially Ravat. Deployed the nets.

October - Harvest was on October 6th, followed by a hard frost on the 8th.  The week prior to harvest it rained several inches and the vines soaked up the water they had been denied all summer.  Many varieties cracked, the worst was Ravat 34, the best was Leon Millot and Regent.
  Cracked Ravat with small berries pictured below;
Below - photo of one of the few Ravat clusters that somewhat filled out;
The juice brix readings taken at the vine was noticeably lower than normal (1-2 brix below what was expected) diluted by the uptake of water from the rains.  In addition it can be expected that the drought served to shut down the vine sugar accumulation and photosynthesis activity for several weeks leading up to veraison and through a portion of the ripening period.  Interestingly the must weights were 1 brix higher.  The vines were hardening off well already with canes on some varieties showing several feet of wood.  Photos below of Leon Millot followed by Lucy Kuhlman

This season I learned a great deal about crop load, especially for vines 3-4 years old in dry land viticulture.  Likely a more experienced grower would have recognized that the delay in flowering of the Ravat 34 was a function of over cropping the vines or would have cropped accordingly in the first place.  Secondly, I should have thinned the Ravat shoots in August rather than September when the berry development was noticeably behind schedule historically and relative to the other varieties.  This would have reduced the water stress and given the berries on the vine a chance to catch up.  As for the other varieties it appears they were cropped properly however, a thick mulch would have helped reduce the water stress.  In short, the long growing season was about 10-12 days better than normal, the heat accumulation was about normal, but the drought significantly reduced the size of berries and the amount of sugar accumulated. Finally, the addition of the potassium and micro-nutrients eliminated the sporadic potassium deficiency identified in previous years.

Sunday, October 9, 2011

Marechal Joffre Wine

Finally - someone is making a Marechal Joffre varietal.  Jost Vineyard in Nova Scotia has been using Marechal Joffre in their red wine blends for decades but in 2010 they kept some of the grapes aside and produced a wonderful red Joffre varietal.

This wine has the character and similarities that one finds in the other more well known Kulhman varieties that came from the same cross - Leon Millot, Lucy Kuhlman, Marechal Foch.  It is dark red, but not inky dark like the way Foch and Lucy Kuhlman can be, more like Millot, perhaps even lighter.  Dark fruit aromas abound with the most notable being plum and black currant - showing its strong similarity to its simblings. Taste is also typical of the other Kuhlman's, with rasberry and cherry the stand-outs although a little less cherry than what I am accustom to in a Millot and over-all less powerful flavours.

This is a very likeable wine, and really reminds me of a Lucy Kuhlman-Leon Millot blend, with none of the herbacousness that I've found in Lucy Kuhlman varietals.  This Jost release recently won a bronze medal at the 2011 Atlantic Canadian Wine Awards and obviously has the ability to stand on its own as a varietal.

Would be nice to see other wineries rethink the notion of blending this variety away.  It can enhance or fortify a variety with less colour or one that has struggled in cooler years to achieve complete maturity.  In addition it ripens about 2 weeks earlier than Foch, yet has about the same disease resitance and cold hardy properties (see link to Marechal Joffre Grape).  For these reasons it is a great variety for the cooler short season locations.

Sunday, September 11, 2011

Grapes Beginning to Ripen Sept 10, 2011

The grapes are starting to colour up and soften and the sugars are starting to accumulate.  Its the time of year to set the bug and/or bird netting out so the critters don't devour your grapes.  Visually, the vines are showing some signs of water stress, particularly the Ravat 34.  For certain I've over cropped the Ravat variety this year and some shoot thinning was required to help relieve some of the stress.  The vineyard has entered into a drought situation as there has been no usable rainfal since July 21st.  Usable rainfal is that which falls in such amount as to enter the ground and replenish soil moisture.  The only moisture the vines have access too is dew which forms overnight and settles on the leaves.  Long range forecast looks like a possibility of rain in about a week.

Analysis of the various varieties shows some are advancing to maturity faster than others, here is a list of average Brix measurements and observations taken on September 10th;
Lucy Kuhlman, Brix 12 - seeds turning brown, softening
Marechal Foch, Brix 10
Triompe D'Alsace, Brix 8 - *still irrigated
Colmar Precoce Noir, Brix 9.5 - *still irrigated
Leon Millot, Brix 11 -  seeds turning brown, softening
Ravat 34, Brix 7
Petite Milo, Brix 10.5 - softening
Cabernet Foch, Brix 7
Cabernet Libre, Brix 9

Lucy Kuhlman pictured below;

Leon Millot pictured below,
Ravat 34 pictured below;

Clearly the earlier Kuhlman varieties (Lucy Kulhman and Leon Millot) and Petite Milo are ripening the fastest.  Interestingly, Triompe D'Alsace and Colmar Precoce Noir are said to ripen even earlier then Leon Millot yet they are behind Leon Millot visually (skin colour and seeds) and by way of sugar accumulation.  However, the Triompe and Colmar have been provided regular irrigation and show no water stress.  Some literature articulates that deficit irrigation at veraison to harvest hastens maturity in grapes.  It is possible, and appears that the irrigation these varieties are receiving has slowed their rate of maturity in comparison to Leon Millot.

Tuesday, August 23, 2011

Mid Season: Grapes are late - Again

As of August 20th we are about 1-2 weeks behind where we should be at this time of year.  Of course we've only been tracking the climate for 5 years so this is yet just another estimate.  Having said that compared to the cool year we had last year we are for sure a few days if not a week behind where we were on August 20th, 2010.

However, the vines are growing well and the grapes are filling out.  There has been some bunch closure on the Leon Millot

and the Ravat 34 is comming along nicely.   

The month of July was about 1 degree cooler than normal and we had double the rain so about 5-6 inches.  This presented some fungal pressures and most of the Kuhlmans are showing very slight powder mildew on the leaves and the Leon Millot and Lucy Kuhlman showing a little on the berries.  The first two weeks in August were warm but the third week was below normal in the day and night temperatures.  We experienced a 3.4 degree low on the 18th of August, however,  this is not unlike last year when we had a similar low around the same time.

The Colmar Precoce Noir and Lucy Kuhlman are just beginning to show some colour change on a few berries and should be into veraison this next week.  The long range forecast into the first week of September shows temperatures above normal to normal with little or no rain.  This is good but some more heat later into September and an extra week or two before frost would be great.

Petite Milo Grape and Wine

Petite Milo is one of several recent hybrids created by Vladimir Blattner of Switzerland.  This variety has several very positive traits including being cold hardy, disease resistant and early ripening.  I can not find specific data on how cold hardy it is but we have had Petite Milo now for three years and the first winter we had it we experienced a -25c and we still had bud break from the cane the next year.  However, there was several feet of snow over the cane.  In comparison I'd rank it similar to Leon Millot.

It is very disease resistant to the typical mildews and has shown no problem on leaf, canes or berries over the past few years. This follows it's performance at vineyards on Vancouver Island and the wine islands.  It buds out early and could be a problem at sites prone to late frosts but at out site it seems to bud out with Leon Millot and not as early as Castel.

It has strong vigorous growth, and is somewhat trailing in habbit rather than having classic upright growth.  The leaves and canes are reminiscent of kuhlman hybrids (Foch. Leon Millot etc.).  The grapes are small as are the clusters, two per shoot, but I've heard from the supplier that there can be more. 

The variety is not an over producer but apparently consistent and will ripen its grapes in very short seasons less than 150 frost free days. However, like Riesling it can be harvested early in this time period or left to hang and continue to ripen.  Grapes can attain high sugar of 23-24 brix, but a little less is common in the shorter season.  This is among the best sugar accumulation for such short season white varieties.  The resulting juice chemistry is good for making wine.

I recently tried a Petite Milo/Epicure (epicure is another Blattner variety) blend that was crafted by Paul Troop of Salt Spring Island. The wine had strong tropical fruit aromas and flavour reminiscent of Riesling and Gewurztraminer.  I've been told this is what the variety should taste like, perhaps a little more Riesling like.  In any event the wine was excellent. It also received a silver medal at the all Canadian wine competition.

I am impressed with this variety so far.  It is the best of the three Blattners we are growing, (Petite Milo, Cabernet-Foch, Cabernet Libre) for our site and look forward to seeing how the grapes come off the vine this year.  We've got about 15 clusters this year and this will give us an idea of ripen times and sugar/acid balances in our short season.

Wednesday, July 20, 2011

Growing Vines in Pots to Plant in Fall - Update

In an earlier blog I have discussed the merits of growing vines the first year in pots then planting them in fall in the vineyard.  There are several values to this;
1) With the vines in pots they can be closely managed, you don't have to go out to the vineyard every day.
2) You can utilize non-commercial irrigation (garden hose) to get the vines established.
3) You can provide specific amounts of fertilizer and control the soil type.
4) You can more easily manage pests that may feast on your vines,.
5) When you plant the vines in the fall they will not need to be watered then on - this is subject to your local conditions.

These are the benefits that I have enjoyed in growing the vines in the pots and planting in the fall.  However, now after 3-4 years of growing and planting vines this way, I can comparing them to vines planted and irrigated from the start in the vineyard and I see differences between them.

The vines grown in pots enjoy all the benefits stated above and after the first year when cut back to a single cane (that becomes the trunk) they require no irrigation and they have grown well.  However the vines planted the first year in the vineyard and grown in the ground and irrigated there seem to reach maturity a bit earlier.  It appears that growing the vines in the pots inhibits the roots the first year and there is then a lag time that the vine has in getting the roots to spread out and established.  The vines also need to get accustomed to the new soil environment in the second year.  What ever the case the vines grown in pots the first season then planted to the vineyard in the fall lag about 1 year behind vines that are grown in the vineyard from the onset.

Wednesday, June 29, 2011

Vineyard Update - June 2011

June 26 I checked on the vines at the vineyard.  The canes on many of the varieties are 1-2 feet long.  The oldest vines, Ravat 34 and Leon Millot look good.  They are now going into their fourth summer and the Ravat 34 (pictured below) have nice flower clusters many have two per shoot. 

The Leon Millot have finally shown some nice flower clusters on most of the vines (pictured below).  These vines were grown in pots the first year then planted to the vineyard in the fall.  I believe that the root system does not get the same opportunity to branch out this first year when grown in pots as it would have if they were grown in the ground.  As such they are a bit behind in growth for fourth year vines, stunted would be the word.  However, they are doing good this year.

The Blattners are also doing well this year.  The petite milo is the best of the group with a cluster or two on nearly every cane and excellent growth.  The Cab Foch is tentative as is the Cab Libre but there are a few clusters on the vines and the growth is good.  We should get some idea of ripening times this year.  There are also some clusters on the ortega and while the growth is poor we should get some idea of ripening time.

Moving Grape Vines in Canada

Last year I had several Marechal Joffre vine cuttings and a few Acadie Blanc cuttings treated in a hot water treatment to destroy any potential pests that may exist on the vines.  The plant material originated from Nova Scotia and was moved to Edmonton.  By law to move these cutting further west to British Columbia they need to be treated chemically or by way of the hot water treatment to kill any pests.  As it turns out the plant material I had treated was poor, and it did not produce any viable plants.  So I did not have to move any plants last year.  These are the rules that one must follow under the Plant Protection Act which is administered and enforced by the Canadian food Inspection Agency (CFIA). 

Let me say first off if you plan to obtain plant material of any kind from another province than the one you are going to move the material to, then you should read this act and familiarize yourself with the regulations.  Reading this Act you find out quite quickly that it is perhaps one of the most powerful federal acts that provides the CFIA inspectors with tremendous enforcement powers.  This is good - it is important that plant material that could be infected with disease or insect pest is prevented from moving from one region to the other, or from outside Canada into Canada, and this is the fundamental reason for the existence of the Plant Protection Act. 

Historically one has to simply look at the west Kootenay region as it pertains to producing fruit, specifically cherries.  The region was known at one time for producing some of the best cherry fruit in North America.  There were cherry orchards abound in the region.  It is believed that sometime in the early part of the 1900 a virus was introduced into the area from foreign plant material that was brought to Canada.  This virtually wiped out the Cherry farms in the Kootenay region within a decade.  Looking backwards to move forward one can see the importance of the Plant Protection Act and the work of the CFIA.

British Columbia is virtually free from many of the vineyard pests that infect eastern Canadian vineyards and for this reason plant material, including cuttings, are banned from being shipped to BC unless they have been treated.  This ban includes the provinces of  Nova Scotia, Prince Edward Island, Newfound Land, Ontario, and Quebec.  As best I can determine New Brunswick is still ok - for now.  But if pest or disease begin to become a preeminent feature in New Brunswick vineyards then I would expect the ban to be extended to that province as well.  This year I obtained some plant material from Nova Scotia, these are the KW96-2 or Evangeline as we call it.  In order to move these to the test vineyard in BC I had to get them treated.

The process to get the cuttings treated and then a movement certificate is quite simple. 
1) First look up your local CFIA office and contact them to see what the rules are for moving plant material from where your are acquiring it from to the place it will be planted.
2)If the material requires treatment, the CFIA inspector will advise you of the different methods - basically there is a hot water treatment or chemical (malathion) dip.
3)You arrange for a time and place to meet with the CFIA inspector so they are present when you treat the plant material (cuttings). 
4)On the time a date of the meeting, you treat the material in the presence of the CFIA inspector and they provide you documentation of the treatment of the cuttings.
5)You then propagate the material in a steril environment with no contact with local plants or soil and in a medium of 50/50 perlite/peatmoss.  The perlite/peatmoss is allowed to be transported across borders but soil is not.
6)When you want to move the material, in my case once the cutting break bud and have some roots forming, you can arrange another meeting with the CFIA inspector to come inspect the plants. 
7)When the inspector arrives, if they deem that your plants look healthy and free of disease or pests, they will give you another document (Movement certificate) that allows you to move the material to its final destination within a certain time frame - about 7-10 days.
8)You then move the plant material to it's final destination, in this case from Alberta to BC, and a CFIA inspectors will often meet you at the final destination to confirm the movement was completed.

The cost for CFIA to certify they material is about $55 for the treatment and $7 for the movement certificate.

The CFIA does an incredible job at this and they have a huge responsibility to ensure the safety of our crops resources.  What I found in dealing with the CFIA in Alberta and BC last year is that they are very willing to help, flexible in as much as they can be to make the process easy for you, and will bend over backwards to accommodate you.  From making the original phone call, the process was easy to set up and go through.  

Saturday, June 4, 2011

Bud Break 2011

Having a look around the vineyard on May 19th I see that some of the grapes are budding out and others are on there way.  We are a few days later than normal but a few days earlier than last year.  Again, the Ravat 34 looks great, approximately 90-95% bud survival (photo below).  The Leon Millot shows some winter damage with some vines showing bud survival between 40% and 70%.  The Castel is looking great, excellent bud survival and emergence given they are just coming into their second year.  The Agria died back to the ground again and I've pulled it out.  It is clear that the conditions at my site are less than optimal for this variety.  The Ortega is doing a bit better with some bud survival and the Regent is similar perhaps even a bit better.  Of the blattners the Petite Milo looks the best, with about 50% bud survival, the Cab Foch and Cab Libre pretty much died back to the ground.  Some of the Acadie are beginning to bud out however, as these were planted in the fall, I expect most of this years growth to be new shoots from the base of the plants.

Looking at the past winter (2010/2011) temperature.  There was a cold snap in late November that saw the temperature plunge to -22c and again another cold snap in February that went as low as -21c.  The winter temperature pattern is that of an on-going freeze-thaw cycle of 10 to 14 days. The information from the data logger shows the cycle starts with the temperature cooling off over a 5 to 7 day period then warming up again over 5-7 days to complete the cycle.  The freeze part of the cycle has temperatures that typically range from -2 to -10 and the thaw part of the cycle sees temperatures in the +6 to 0 range.  This pattern starts at the end of November and continues on to the end of February.  Below is the Oct-Dec 2011 temperatures - click image for larger view;

This freeze thaw cycle may be causing damage to the buds on the vines as the buds may be forced in an out of dormancy.  There is alot of snow in the winter at the vineyard site (February 2011 photo below).  Mid winter snow is about 3 feet and could provide some protection from the freeze - thaw cycle so were going to lower the fruit wire on the Leon Millot to 24" to see how that affects the bud survival next year.

We also added some fertilizer and micro-nutrients this spring as some vines showed deficiency last year. This can also have an affect on the hardiness of the vines and bud survival rates.  The fertilizer is a basic 8-8-8 blend, and the micro-nutrient amendment is Scotts Micromax. 

Overall, the vineyard is looking good this year.  In June, we'll see how the vines leaf out and the fruitfulness of the buds.

Friday, April 15, 2011

Evangeline Grape

This grape is officially known as its research name KW96-2 and as far as I know, hasn't been formally named.  Although this is not for us to name, we're for now calling it Evangeline, relating to it's Nova Scotia pedigree, as this grape is far to nice to have such a clinical name.  This grape was created by Dr. Jameison of the Kentville, Nova Scotia agriculture research station.  It is a cross of St. Pepin and Siegerrebe.

St. Pepin is a Hybrid bred in the United States from Seyval Blanc and Minnisota 78 by Elmer Swenson.  It is cold hardy to about -32 c and is known to produce white wine grapes with characteristics and flavours similar to Riesling.  It also possesses moderate disease resistance to both downy and powdery mildew. Siegerrebe was bred in Germany and is a cross of Madeline Angevine and Gewurztraminer.  It is very early grape with low disease resistance but from the grapes, fruity low acid muscat wines are made.

The resulting cross that resulted in KW96-2 possesses the cold hardy disease resistance of St. Pepin with the early ripening muscat flavouring of Siegerrebe.  Progressive testing of this variety at the Kentville research station and in test vineyards in Nova Scotia have found that this vine is a moderate producer of grapes that ripen 1-2 weeks earlier than L'Acadie Blanc, the Nova Scotia white wine standard. A few years back I was at the research testing station in Kentville in September and while L'Acadie berries were still hard and tart, the berries of KW96-2 were softening, sweet and had distinct flavours.

There is alot of excitement surrounding this new variety and several other crosses that have been created at the research station in recent years.  Tests of these new vines and production of grapes from them have lead to production of wine and wine quality testing.  Of all the varieties tested, KW96-2 rated among the highest by wineries and wine makers and did equally well when presented to a panel of seven (7) regional sommeliers.

This could be a very valuable grape in locations with short to very short seasons and moderately cold winters - locations like ours.

Tuesday, April 12, 2011

Quebec - Hardy Grapes and Nice Wine

A few years ago I was in Montreal for business and had an extra day on hand.  Having heard of the long established viticulture and wine industry in Quebec, so I rented a car and headed out to the "Eastern Townships" to have a look.  The Eastern Townships is an area just south and east of Montreal in the area of Dunham.  It takes a few hours to get there but the drive is great.  I stopped at three of the long established vineyards/wineries in this area and found that the varieties that are being grown include the likes of Seyval Blanc, Vandal Cliche, Aurora, Marechal Foch, Sabrevois, St. Croix, and Frontenac among others.

Generally speaking this area gets quite cold in the winter, too cold for Foch, Seyval or Aurora.  However, those who have been practicing this intense cold climate viticulture in Quebec have unique techniques to reduce the chance of winter damage of these vines that have marginal hardiness for this climate.  Often the vines are removed from the trellis and put on the ground before winter.  This is what we do with our St. Croix in Edmonton.  Often the snow cover alone is enough to protect them but sometimes they are covered in straw or even buried in soil for further protection from the cold.  I tasted several wines in this trip and found some that were excellent and others that were alright but none that I disliked.  Of course everyone's tastes differ in what they like and dislike in the flavour and characteristics of wine.

I have yet to visit this region since then but on a recent trip to Montreal I went looking for some Quebec wines in the local wine store.  I asked the clerk if they had any in stock but was advised they did not carry any.  They suggested that I go to another specialty wine store at the Eaton Centre. However, I continued to peruse what wines in the store and stumbled across a small display of Quebec wines that they did in fact carry.  I advised the clerk that they did have Quebec wines and they were astonished.  I've talked to other who live in Quebec and many don't know they have a vibrant viticulture and wine industry.  Others that have heard of Quebec wines are reluctant to try them, they have an impression that the wines are inferior to those typically found in the wines stores.  In fact, the wines being produced from the Quebec viticulture industry can be excellent and many are winning awards on the national scale. 

I brought a few of the Quebec wines back with me and have since tried two of them.   The bottle on the right is from Domaine Du Ridge from St. Armand, Quebec.  The name on the bottle is Clos du Marechal and in reading the vineyard web site it appears that the wine is made from Marechal Foch and possibly blended with some Lucy Kuhlman - however, I don't speak or read french, so this is a bit of a guess.  If this is Foch, then this was truely amoung the best Foch wines I have ever had - FANTASTIC.

The Bottle in the middle comes from L'Orpailleur vineyard in Dunham, Quebec.  This wine is made from Seyval Blanc and is classic Seyval - fruity, well balanced, very nice. 

The bottle on the left is from Vignoble Riviere du Chene located in St. Eustache, Quebec.  I gave this one away as a gift to a friend down the street who grows Vandal Cliche in his back yard.  This is white wine and the bottle is named William and is made from Vandal Cliche grapes.  Don't know much about them except that they apparently make a very nice dry white wine and this variety of grape was actually created in Quebec.  If the other two and those I've had previously in Quebec are any measure of what this one is like, then it should be great.  Hoping for an invite from the neighbor to try this one out when he opens it up.

If your out that way to visit or if your live near these wine regions you've got to check them out.  You'll definitely find something you like.  Looking forward to the next visit!

Monday, February 28, 2011

Leon Millot Grape and Wine

This is another little hybrid that was developed in France.  In fact it is has the same parentage as its more well known sibling Marechal Foch.  Two other hybrids came from this same cross including Marechal Joffre and Lucy Kuhlman.  Leon Millot is an early ripening black grape with small bunches, often 2-3 per shoot the largest usually about 70-80 grams.

It is cold hardy to approximately -25 to -30 c and while bud break is relatively early it is a little later than Foch making it appealing to those where later spring frost can be an issue.  It is also known to ripen a few days earlier than Foch but these accounts appear somewhat subjective.  Typically it ripens in 135-140 days, with flowering to harvest being about 85-90 days.  What is known is that it regularly ripens to the same brix as Foch but does not have the high acidity problems that Foch can have in some years.  In fact the juice chemistry is often excellent for wine making.  Leon Millot is relatively disease resistant but can suffer from powdery mildew. In our two years with fruit on our vines I've seen no disease except some late season mildew on the canes, post harvest.  However, overall Foch is suppose to be more cold hardy and disease resistant.

This grape produces a highly coloured wine and was apparently used as a blending component to lighter coloured wines such as Pinot Noir as it enhances the colour without altering the quality.  While the deep garnet colour is typical and valued,  perhaps most important of this disclosure is that the quality of the wine made from Leon Millot blends well with Pinot Noir without altering its quality significantly.  This is a testament to the quality of wine that Leon Millot can make.

Other accounts share in this sentiment in that the grape can make a better wine than Marechal Foch with better chemistry and more distinct berry aromas (see link).  In the several that I have tasted I'd lean towards the Millot as being a better wine than the Foch.  Perhaps as important is the spectrum of wines that can be made from this variety from rose' to medium bodies reds.  This allows some flexibility in the vineyard and winery.

Leon Millot is widely grown on Vancouver Island and Nova Scotia in Canada and rarely outside these locations.  However, there is a vineyard in the Okanagan that grows Leon Millot and the wine has received alot of attention for being excellent.  The vineyard is Hollywood and Wine and is located in Summerland, BC.  Here is a link to the vineyard,.  Several wineries in Nova Scotia grow this including Domaine de Grande Pre and Jost Vineyard.  Mistaken Identity Vineyard and Gary Oakes Vineyard are two wine Island vineyards growing this variety.

Thursday, January 6, 2011

Diurnal Fluctuation and Degree Days

DDG or degree days growing is widely accepted as a measure of a locations ability to ripen a crop of grapes. There are few other measures as well including the LTI (latitude/temperature index) and calculation of the mean monthly temperature of the warmest month. However, in most of the reading I’ve done DDG is most widely used and also accessed when comparing what varieties will mature in a given number of degree days. For instance, one document on grapes varieties grown in British Columbia describes that you need at least 850 degree days growing and 135 frost free days to grow the earliest wine grapes in BC. It goes on to state that 1000 degree days are required to grow mid-season varieties.

Degree days for different crops are calculated to different base temperatures. For grapes the base temperature is 10 degrees celcius because generally speaking, grapes begin to grow in the spring once the average daily temperature is 10c. There are some hybrids that begin to grow at temperatures a few degrees cooler but again 10c is the general rule. Other crops like corn use 5 degrees celcius. Degree days for a particular day are calculated by taking the average of the sum of the day time high and the day time low and subtracting 10. If your day time high was 26 and the day time low was 12 the average for the day would be 19 (26 + 12 = 38, divided by 2 =19). Then you’d subtract 10, which leaves you with 9 degree days growing above 10c for that day.

You can easily do this for each month as well. For instance if the average daily high for the month was 24 and the average low for the month was 11, the monthly average would be 17.5 (24 + 11 = 25, divided by 2 = 17.5). Then you subtract 10 from the average which leaves you with 7.5 degree day for each day of the month. So if this were July, with 31 days, you add 7.5 degree days for each of the 31 days in July which would give you 232.5 degree days growing above 10c for the month.

So really what we are calculating is how much heat above the 10c base was accumulated over a particular time period. This is important, specifically  “above 10c”, especially if you are in an area that is prone to night time lows below 10 degrees celcius. Temperatures below 10c have a negative impact on the growth, development, nutrient uptake of a grape vine. Research has shown that when a vine is exposed to temperatures in the 5c-10c range the growth slows and has a negative impact on the vines ability to metabolize carbon dioxide and on the photosynthesis ability. The effects will have a further lingering/lag effect even as day time temperatures return to above 10c which in turn causes a lag time in vine development and grape maturity.  Photosynthesis is best in the morning, so this lag time inhibiting photosynthesis at this time of day is detrimental to growth.

So if you examine temperature profiles for two locations the degree day accumulations may appear the same however, the locations ability to ripen grapes may be better in one location than the other as the day-night (diurnal) temperature swings are less. For instance a location with a monthly average day time high of 24 degrees and monthly average nigh time lows of 14 degrees would have a monthly average of 19 degrees. This location with the average night time lows of 14 degrees would be expected to have few nights with temperatures below 10c. Another location with monthly average day time highs of 28 degrees and monthly average lows of 10 degrees would have the same monthly average of 19 degrees. However, this location would be expected to have several nights with temperatures below 10c and with it one could expect some negative impact on growth and potentially to ripen grapes a few days later than the other site. In fact, scientists who study the effects temperature on vine development often use degree day hours to calculate the accumulation of hours rather than days above 10c as this can be a more accurate assessment of accumulated heat.  Of course there are so many other factors as well, wind, hours of sunshine etc., so this is simply a generalization.

But this does become important when one considers that 850 degree days growing and 135 frost free days are required to ripen the earliest grape varieties in BC. If you get 850 degree days but the development and ripening is delayed most mornings due to cool night time lows then one may need more than 135 frost free days to ripen the grapes - perhaps 140 instead. With this in mind one has to remember the principals of frost avoidance not only to safeguard from frost but to help ensure an optimum vineyard mesoclimate. Clearing trees so cold air can drain away, short mid row cover or none at all, and wind breaks to deflect cold air entering your site can not only stave off frosts but can raise the average night time temperature and possibly improve the vineyard conditions throughout the entire growing season.