September in the Tamar Valley, Tasmania

At 41 degrees South the first warmth of spring starts movement of the sap in the vines. The buds swell and by late September most shoots have burst to 1st leaf.

 

September Vineyard

Tasks in The Vineyard

 

1. Check Bud Spacing

Scott Henry trellis system

Scott Henry Trellis system

The Scott Henry trellis system is ideal if your vines are vigorous due to spacing or the composition of your soil.

I have found that this trellis system gives a good balance between canopy and fruit set.

I mistakenly read too many notes from the USA when I planted my vines and spaced them at 1.8 centres with 3 metres between rows.

Whilst this allows excellent manouverability for mowing and other operations, cool climate viticulturalists are now advising

a spacing of 1.2 metres between vines.

In the first 2 vintages I experienced significant problems with a vigorous canopy.

It is for that reason that I have opted for a Scott Henry trellis system to control the vigour of my vines.

The system balances vigour by allowing a proportionately greater fruit set whilst still allowing maximum light

for the vines to develop premium quality fruit.

I allow 6 buds for each of 4 arms plus up to 4 spurs for next year's replacement canes.

This potentially allows for about 40-50 bunches of fruit ( about 3 -4kg of fruit per vine).

Allowing any more than this endangers overcropping, which grape varieties such as Pinot Noir are prone to.

This causes great variation in the crop from year to year as the potential energy of the vine does not vary a great deal.

The developing buds for the next year's crop do not get the sugars needed to develop properly leading to a poorer crop in the next year.

For premium fruit quality you can thin this yield to potentially about 2-3 kg per vine,

but I have found that quality is excellent if kept to the bud count I have outlined.

Scott Henry Layout

2. Clean up under the vines

A great season always starts with great preparation. I try to give my vines the very best chance of producing

a premium crop that will utimately make the best wine for the vintage.

Weeds and grass growth under the vines will harbor pests and diseases that will compromise this aim.

I always give at least 2 days to tidy up under my vines prior to bud burst.

There are many growers who argue that this is unnecessary.

I would argue that they would have far more variation in the quality of the fruit they produce

and ultimately compromise their wine by not establishing and maintaining healthy practices in their vineyard.

I always spend a day or so hoeing weeds under my vines. If the season allows, a glyphosate based spray can afford easy killing of weeds.

I am still uncertain about the longer term effects of this spray , so I try to minimise its use.

This year's weather made it impracticable to apply with good effect before bud burst so I ended up hoeing weeds anyway.

As in previous notes , a spray of lime sulphur will assist in the control of mites and to some degree

the overwintering spores of Powdery Mildew.

3.Check fruiting wire tension

The weight born on this wire should not be underestimated.

Movement in the end posts due to wet soil and increased tension after pruning may lead to this wire being slack prior to bud burst.

Check the tension prior to bud burst and adjust it if necessary.

I use a ratchet tensioning devise on all my wires so that adjustments can be made at any time if necessary.

It is better to adjust the tension of these wires prior to bud burst as buds may be damaged after they have emerged if adjustment is late.

ratchet

4. Fertilise vines

In their early growth , vines need high levels of nitrogen and then increasing levels of potassium to establish good flowering and fruit set.

I have sought out a local feed lot that regularly clears the effluent from the feeding area of cattle and makes available the manure at a cheap rate.

This would be impractical for a commercial vineyard to undertake, but I have used it annually with great success.

An application of a fine layer under each of the vines is adequate.

The irrigation over the growing season will ensure that the nutrients are supplled to the vines in a timely fashion.

5. Bud burst

In mid September the vines come to life and the buds will burst into 1st leaf.

I have 2 varieties in my vineyard, a little unplanned through a less than vigilant collection of cuttings for my first planting.

I have 10 Cabernet Sauvignon vines within my Pinot Noir MV6 vines.

This is not a difficulty as the vines are distinctly different in leaf shape and in fruit.

I have distinctly marked the CS vines, but the point I wish to make is in the timing of bud burst.

The Pinot Noir vines in my vineyard are 2-3 weeks earlier than the Cabernet Sauvignon.

This will ultimatley lead to about this difference in harvesting of the 2 varieties.

The picture below demonstrates this. This photo was taken on September 25.

The vine on the right is Pinot Noir, clearly in early bud burst.

The buds on the left are Cabernet Sauvignon , only in early bud swell.

The Cabernet Sauvignon vines reached the same stage 3 weeks later this season.

I am confident this will be reflected in the sugar levels taken in March to determine the best harvesting time.

I would expect that the CS fruit will be at least 2-3 weeks later than the PN.

Pinot_cabernet_lag

Watch a video of the difference between Pinot Noir & Cabernet Sauvignon vines

6. Check Irrigation supply

If you haven't already done it, I suggest you test your irrigation system.

Remove end plugs first and flush all lines so that sediment in the lines is cleared.

Check all drippers are working well and take a check of your rate of supply.

A measuring flask under a dripper over 15 mins will give you an estimate of the water your vines are receiving. x 4 = rate in mls per hr.

Clean the filter of your irrigation system, and if you use a nutrient inversion, check that there is no crystalised sediment remaining in the line from last season.

It depends on your soil profile and the weather of course as to how much you should water your vines.

I will give more detailed guidance on this in future months.

7. Frost

Frost in the early season can be most damaging to your vines.

I am fortunate in that my vineyard is close to the Tamar estuary, which modifies the extremes in temperature.

A frost of -2 degrees celcius or greater may seriously damage your young shoots and retard the growth or alter the fruiting potential of the vines for the season.

I have experienced one season when the temperatures were forecast to reach -3 degrees celsius.

Having a reasonably small area, I decided to do everything I could to limit frost damage to my vines.

I lit a brazier in the middle of the vineyard

( area 300 square metres) and at 4 am I turned on the irrrigation system to raise the ground temperature.

I managed to survive with no damage when larger holdings in the same district suffered signifiicant losses.

If you are keen, I would recommend you at least turn on your irrigation 2 hours before dawn when a severe frost is forecast.

Raising the soil temperature by a degree or two makes all the difference.

8. Spraying Program

Now is the time to think about your spraying program for the year and to consider a preventitive program applied every 10 days

and when necessary after rainfall.

Think about the grape diseases that are established in your area.

In the Tamar Valley, the first consideration is Downy Mildew if weather conditions are suitable for this infection.

12mm of rain at a temperature of 12 degrees Celcius or more over a 24 hour period will present conditions suitable for the development of this fungus.

Check this link for viticultural notes on the disease.

In the first 2 months of my vine growth I apply a copper based spray for Downy Mildew every 10 days as a peventative measure.

As the season develops and the temperatures rise, Powdery Mildew will become an issue, so you need to condiser how you will vary your sprays to control the spread of this disease.

A certain amount of Powdery Mildew overwinters in the buds from last season, so I feel it is necessary to start applying sray

as a preventative every 14 days as soon as the temperature reaches 18 degrees celsius or more.

I shall write more about this disease and the methods that can be used to effectively control it in the October notes.

http://www.winetitles.com.au/diagnosis/index.asp This link is a fantastic aid to diagnose what is happening in your vineyard.

Next Month:

Bud thinning

Sucker removal

Spraying program

Wine racking

Bottle cleaning

Testing wine

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