leaves per grape cluster
 

The book "General Viticulture" suggests that red wine grapes need 20 - 26
leaves per cluster to ripen effectively.

Question: are the number of leaves per cluster limited to the shoot the
cluster is growing on (what if there are two clusters growing on one shoot.
Does there need to be 40+ leaves on one shoot to contribute to those two
clusters?)? If one wanted to be meticulous and count leaves on a single
vine, could the number for the whole vine be averaged for X amount of
clusters?

Jeff

jeff wrote:

> The book "General Viticulture" suggests that red wine grapes need 20 - 26
> leaves per cluster to ripen effectively.
>
> Question: are the number of leaves per cluster limited to the shoot the
> cluster is growing on (what if there are two clusters growing on one
> shoot. Does there need to be 40+ leaves on one shoot to contribute to
> those two clusters?)? If one wanted to be meticulous and count leaves on a
> single vine, could the number for the whole vine be averaged for X amount
> of clusters?
>
> Jeff

Good question. I just recently read an article in "Practical Winery &
Vineyard" - May / June 2005 by Eben Archer and J.J. Hunter (page 45) that
stated among a lot of other things that leaves that are 80 to 90 days old
no longer contribute much to the vine. They state that it is the younger
leaves higher in the canopy and on laterals that contribute to ripening.
To me this means count the leaves in the laterals. It also makes me feel
better about pulling the older basal leaves around the clusters to permit
more air circulation and exposure of the buds on the lower shoot to
sunlight for next years crop. I suggest reading the whole article and
derive your own conclusions.

On Wed, 29 Jun 2005 "jeff" > wrote:

>The book "General Viticulture" suggests that red wine grapes need 20 - 26
>leaves per cluster to ripen effectively.
>
>Question: are the number of leaves per cluster limited to the shoot the
>cluster is growing on (what if there are two clusters growing on one shoot.
>Does there need to be 40+ leaves on one shoot to contribute to those two
>clusters?)? If one wanted to be meticulous and count leaves on a single
>vine, could the number for the whole vine be averaged for X amount of
>clusters?

I think just that shoot contributes. I need to put more fruit on, I
think, which I believe slows the vegetative growth. I've noticed some
Frontenac shoots with mega clusters that seem to put out much fewer
leaves. Getting that balance right is a trick. Keeping the birds
away will be the next trick :)

I'd guess the real ratio is the weight of the grapes to the surface
area of the leaves (instead of cluster number to number of leaves),
and as someone else mentioned, the older darker leaves seem to be less
efficient.

Bill