Healthy vines


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
Reply to
michael

Just remember when you start killing wasps, they are efficient and necessary predators that control insects that cause worse damage and carry disease. Steve
Reply to
Steve Peek

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.
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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
Reply to
shbailey

Thanks for that,Stephen.I have two questions.
1)When my grapes are ripening,the lower leaves seem to die back naturally.Is this the time to look for mineral deficiencies e.g.potash,or at an earlier stage? 2)What are the symptoms of nitrogen deficiency or excess?
Regards,Michael
Reply to
michael

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.
Reply to
Paul E. Lehmann

The lower leaves dying back during ripening is a natural occurrence. these are the first leaves to open during the season. Leaves reach maturity and are no longer contributing after about 60 to 90 days. It is the young leaves at the top of the vine that are contributing to photosynthesis and ripening.
Reply to
Paul E. Lehmann

Michael,
At this time of the year, the old leaf die back is natural. If it occurs prior to veraison, it can be a sign of drought stress (which can be lessened by the use of mulch). Drought stress may be manifest by signs of nutrient deficiencies. If you get yellow/red/purple streaks in your leaves prior to ripening time, it is nutrient deficiencies showing up like in the pictures on the link.
Nitrogen needs are variety dependent to a degree. I have seen Merlot described as a "nitrogen hog", meaning if it has a lot of available nitrogen it will grow like crazy and not produce many grapes. If a vine has rampant growth but little fruit production, it probably has too much nitrogen. If it is a weak grower with small pale leaves, it may benefit from a little extra nitrogen and other nutrients.
Stephen
Reply to
shbailey

Hi Paul, Although I do not live in a semi-arid part of the world,my sloping dry limestone south facing soil does dry extremely quickly during the summer.The grass on the adjoining orchard becomes a pale straw colour for a couple of months,and the planting of fruit trees in the orchard is almost impossible without regular watering in the first couple of years.So it may be the case that mulching in March helped the vines over the very warm dry June period,and stopped any powdery mildew developing.In other years,I have some powdery mildew,even though I spray regularly with wettable sulphur.This year I have not detected any powdery mildew on any of my four varieties of vines.So,maybe the jury is still out as to whether the mulching has helped the vines in my particular situation,but I am tempted to mulch again next year. Best regards Michael
Reply to
michael

Michael,
It's well documented that fungus preys on unhealthy plants. Plants that are stressed or made to suffer. Sound familiar? Also the mychorrrizal fungus in the mulch is helping the roots and vine. On the lateral issue, As I said before, laterals are produced by the vine after bloom to help with ripening. Depending on when bloom is is when you should stop pruning laterals. I wouldn't base my lateral pruning based on a date but on the date of bloom. The vine will most likely not produce laterals until after bloom and the most important set of laterals are the ones closest to the base of the shoot ( closest to the grapes).
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Reply to
doublesb

If you had a sunnier and warmer season than usual thus far, that could be the major reason for lack of powdery.
How many rows do you have? Could you do an experiment and mulch some and don't mulch others and see if there is a difference?
Reply to
Paul E. Lehmann

"Could you do an experiment and mulch some and don't mulch others and see if there is a difference?"
I already did that. There is a big difference in the mulched vines compared to the unmulched vines. Micheal is just confirming what I and shbailey have seen. Why don't YOU do the experiment? You seem to be a typical viticulturalist, a stubborn dinosaur regurgitating old myths.
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Reply to
doublesb

My response was to Michael - NOT you.
I don't need to. My vines are healthy and there is no issue with lack of moisture where I live.
WHY don't you answer my questions? Where do you live. What varieties are you growing and how many vines do you have? Have you ever worked at a commercial vineyard?
Hardy har har. I am a Geologist but putting me in the realm of dinosaurs is stretching it a might.
Reply to
Paul E. Lehmann

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