shbailey wrote:

> On Sep 18, 4:42 am, michael > wrote:
>> I thought that I would try again to further my understanding of
>> observations on my vines in England this year,based on the very useful
>> replies and discussion.There will always be disagreement,but as
>> someone new to growing grapevines,I hope that I can understand the
>> issues.I apologise to doubi..for my recent comment,and hope that he
>> can continue to help.
>> Let me try again to summarise my recently gained knowledge:
>> 1)Using wood chip as a mulch on the surface around the vine can
>> greatly help in the stabilisation of upper soil moisture content,and
>> will not affect the nitrogen of the vines-rotovating or digging in
>> wood chip will rob the soil,and this is my gardening experience.Garden
>> compost could be even better,as it introduces a living worm population
>> which may help soil texture.
>> 2)Wasps or other insects are not the source of primary damage to
>> ripening grapes,but can spread the rot to other grapes in the bunch.A
>> primary source of damage could be a heavy rain shower,causing
>> splitting,followed by wasps,etc moving in.I think that this is what
>> happens with plums after they split when nearing ripeness.My culling
>> of the majority of the wasp population will still help,I believe.
>> 3)I thought that darker vine leaves to be an indicator of too much
>> nitrogen.I would like to know what the indicators are for vines
>> needing more phosphates,or potash,so that I know what fertiliser to
>> add to my compost.
>> 4)One indisputable fact is that my vines and grapes are sofar much
>> healthier this year. I believe that probably the main cause is the
>> long very warm dry spell here in June-but I do not really know.It
>> could be the compost keeping moisture levels stable.
>> 5)My original post was about pruning of laterals or sideshoots for
>> vigorous vines in a cool climate.My policy now is to remove most of
>> them in June and July to prevent a dense canopy developing,thus
>> encouraging powdery mildew,and then leave them alone after veraison to
>> have maximum leaf for the ripening period.
>>
>> I hope that my understanding is improving and welcome your comments
>>
>> Michael
>
> The following link provides pictures of grape leaves with various
> nutrient deficiencies. Potash (potassium) and magnesium are the most
> common. Magnesium can be easily supplied with a few spoonfuls of
> Epsom salts. I read the other day that grapes usually don't need
> added phosphates. http://www.honeycreek.us/leaf_chart.php
>
> You hit the nail on the head about the benefit of mulch. If you had a
> long warm, dry spell and your vines remained healthy, it was due to
> the stable moisture levels enabled by your mulch.
>
> Stephen

It was probably the long warm, dry spell that made the vines healthy. Vines
love and thrive in those conditions.

I don't think Michael lives in a semi-arid part of the world requiring
mulch.