March in the Tamar Valley, Tasmania

Harvest Month

With our nets on and hopefully stable weather, we are in a position to start testing the readiness of our grapes for harvest.

Rain at this time of the year is a mixed blessing after verasion.

The best time to apply reasonable quantities of water is during the berry growth phase so that the berries grow to a reasonable size before they change colour and start to ripen.

Rain after veraison can swell the berries to the point where some burst. They then become a prime target for European wasps and botrytis.

Having followed my guidance you will have sprayed your vines for botrytis prior to putting on the nets. The main danger is wasps.

European Wasps

The evidence against these determined little scavengers actually attacking grapes is not good. The weight of evidence shows clearly that they merely harvest the sugars in damaged grapes.

I have watched these insects become intoxicated with the fermenting sugars on grapes and drunkenly fly back to show me where their underground hive was.

It is usually a hole in the ground with fine grains of floculated clay distributed around it.

WAIT until dark. The wasps are inactive then and will not react to your approach until it is too late for their survival. A good dose of carbaryl powder puffed from a used detergent bottle is a great solution for killing these pests. I follow it by stuffing the entrance to the hive with a distillate soaked cloth. By morning there is no action about the hive.

Sounds simple BUT the greatest difficulty is finding the hive.

Nevertheless, I feel we probably need to expect a little ( about 10% damage from these insects and cut our losses).

Determining Sugar Levels.

You should take regular weekly samples from mid February ( Melbourne district) and early March ( Tamar Valley) of 100 grapes taken from representative places in your vineyard. Don't include diseased berries and avoid berries that have not thoroughly veraised.

Using your hydrometer, calculate the potential alcohol level of your crop using the table here.

1.1010 or240 Brix will give you a potential alcohol of about 13.5%- about right for Pinot Noir.Any higher than this and you start to disguise the subtle fruit characteristics of fine Pinot Noir.

I have discussed this timing pretty well in the wine making process here.

You may get the message that excellent viticulture is essential for premium wine making.

I sincerely believe it is.

The winemaking is relatively straight forward if you start with excellent grapes.

Read about the preparations for wine making in my In The Cellar notes.

One more topic for this month.

Preparing your Vines for next season.

It is so very easy once you have picked your grapes to walk away and forget about your vines which have done their job for the year.

DON"T DO THIS!

The stress of losing the fruit is considerable for the vines.

Give them a water as soon as you have picked the fruit and remove the nets as soon as practical.

They will repay you by putting the remaining energy of their leaves into establishing healthy buds for the following season.

The fruit for next year is established in the preceding season.

Don't ever forget this. It is most important.

How would you feel have run a marathon to be deprived of water at the end?

I believe your vines are like this. Look after them and spoil them a little. They will repay you by healthy growth over the next few weeks until they shut down for the winter.

 

 

 

 

 

This page was last updated on 15/03/2010