The MGS Forum
Plants for mediterranean gardens => Fruit and Vegetables => Topic started by: westyboy on February 10, 2013, 09:08:36 PM
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I have over the past couple of years structured two Grapevines to create an ideal canopy.
They cover our courtyard, (eating area) perfectly in the summer.
I read somewhere that vines need nothing other than a good watering from time to time.
And this seems to have produced a healthy looking vine.
Even though it does produce plenty of grapes. I am sure the quality of the grape could be better.
Do Grapevines need a feed?
Do I reduce the number of bunches?
Does the Grapevine need a routine spray?
The local growers, cover their bunches with bags, is that necessary for a small setup?
Any Grape/Grapevine tips much appreciated ???
Roy
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Do you know what variety the grapes are? Some wine grapes are not particularly palatable and others are not producers of big bunches (eg Pinot Noir). Dessert grapes are usually watered with drip irrigation to fill the berries and make them more deliciously succulent. The bags are a protection against birds and wasps. If your neighbours do this and you don't the birds and wasps may well make a beeline for your vines. As to spraying, downy mildew may be a problem if you do not. They grey powder that develops on the berries is neither attractive nor palatable. Do your neighbours vines get downy mildew - it usually appears mid to late season. tn
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I am not sure of the varieties Trevor, but they are dessert grapes and very tasty.
I did notice the grey powder last year, what do I spray to avoid that?
Last year both vines were full of grapes, should I reduce the bunches, to reduce the stress on the vine?
So the bags are purely to protect against the wasps and birds,
Thanks Trevor
Much appreciated
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The blue tint you often seen on the leaves of commercial vineyards is a copper solution, usually Bordeaux Mixture, which is commonly applied to prevent grey mould. (Although it is certified for organic grape production, some purists claim it isn't really organic.)
There are other products available to commercial growers which are more effective - and much more expensive. As far as I know the only product amateurs are allowed to buy for grapes is Dithane (mancozeb). There are so many different formulations of Dithane that it's important to use only a formulation that gives specific instructions for use on eating grapes - and you'll probably find that it advises you not to use it at all within several weeks of harvest. (Also, it will get washed off by rain, so by the time you're ready to eat your grapes it will almost certainly no longer be any protection.)
Taking some leaves away around individual bunches - so long as you leave plenty of leaf cover - does reduce the risk of rot, by increasing air flow.
Don't worry about all those grapes stressing your plants. Vines are almost impossible to overstress. BUT if you thin the bunches you will get better, plumper fruit. People who want picture-perfect grapes even thin the individual fruits within the bunches, with a pair of long sharp-pointed scissors.
Grapes like other fruits do yield better with fertiliser. Our neighbour in Greece uses only well rotted goat manure in spring, for his excellent grapes. An easy option which we use for protected grapes in the UK is watering with tomato fertiliser every three weeks - but stop doing that when the fruit starts to show colour. Keep an eye on the leaves; odd discolouration gives good warning of any nutrient shortages.
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Thanks Alisdair
That has answered all my questions and more.
Roy
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Grapevines respond to fertilizer like any other plant. N will give the best response applied late autumn. Mineral deficiencies are common and will take a " qualified" person to identify and correct. Foliar fertilizers do not do much good.
If you are happy with the size and number of your grapes, do nothing. However if you wish to impress there are two options, either berry thinning or grape bunch removal. I think trial and error would be the best advice for the latter technique.
Commercial grape production requires routine spraying.This may not be the case for you.. Find out what your neighbours do. Spraying willy nilly with XZY product is not the way to tackle pest control. Find out the problem, ask neighbours, understand the lifecycle and chose an appropriate remedy..Please ask. There are two mildews, both similar. Downy mildew tends to be a "wet" weather disease and "powdery" is a hot weather disease. In your case it is probably powdery. Sulphur is old widely used and not very effective. dithane s OK for D mildew whereas benlate, karathane, triazoles are much effective against P mildew.
Not sure why they cover bunches with bags ..unless its Japan.....but it could be against wasps which are a plague certainly in the Rhone valley.
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If you do decide to apply fertiliser in autumn rather than spring, give it while the leaves are still plump and green in the early autumn. It's no use giving fertiliser once the leaves are no longer doing their job efficiently - particularly on light soils. The time vines are nitrogen-hungry is while they are growing rapidly, from bud-break in the spring onwards.
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I doubt that you will get much fertilizer uptake if itis applied too late when conditions start to dry out.
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:o Many amateurs here spray their grapes, and roses, asters, autumn flowering and fruiting plants subject to grey moulds, with a dilute milk solution and swear by its efficacy. I'm do not know the ratio of milk to water, nor do I know if they use whole milk, soy milk, reduced fat milk, cacium enriched milk, butter milk, pasteurised milk, goats milk but I suspect it is most likely just plain ordinary cows milk. Has anyone else heard of this treatment? tn
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I saw an abstract from a Chinese Paper: Antifungal Activity of Bacillus coagulans TQ33, Isolated from Skimmed Milk Powder, Against Botrytis cinerea (http://www.ftb.com.hr/23.Wang_et_al.pdf), which concludes with: The biocontrol effect of B. coagulans TQ33 on preventing growth of B. cinerea by the greenhouse tests suggest that B. coagulans TQ33 has great potential for the control of plant pathogenic fungi.
Dairy products are briefly mentioned as an alternative to sulphur treatment in another article, Organic Farming: Managing Grapevine Powdery Mildew (http://www.dpi.vic.gov.au/agriculture/farming-management/organic-farming/organic-viticulture/grapevine-powdery-mildew), and interestingly, it also mentions that: ‘High nitrogen status increases the susceptibility of vine leaves to powdery mildew. This effect is more pronounced when combined with low UV light levels (Keller et al. 2003).’ So too much fertilizer at the wrong time is probably not a good idea.
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I have just been reading about spraying with milk. The article suggested 10% Dairy milk to water.
Milk has replaced Bicarb, because the bicarb even though effective leaves a taste on the grapes. And milk doesn't.
The article explained how good milk was as a spray treatment, but no one could understand why it worked.
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Spraying with a milk solution? That is exactly what I have been advised to do if I am trying to make an 'aged' look on new stone in garden walls. And it is said to improve the look of new relief stone carving.
That must mean that the microorganisms which give patina to stone differ from those worrying grapes?
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;) And then there was Cleopatra who bathed in asses milk. Maybe the stuff is a universal panacea? Should be bottled! :D tn
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If you wish to age stone spray with a FYM solutuion (farm yard manure).
If you are going to the bother of spraying for goodness sake use something that is effective. There is no data comparing the efficacy of milk, with bicarbonate, with sulphur, with mirrors.
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Please note that Alice has started a new thread on the topic of Ageing Porous Materials, which will pop up if you click here (http://www.mgsforum.org/smf/index.php?topic=1225). (That would be the place to add any further comments on how to make new stone or terracotta pots look older, etc.)