Anyone out there know of a good rule-of-thumb for general water demands for a vine? All the data I can find calls for an excess of
27,000 gallons per acre per week. That equates to 80 hrs per week irrigation (based on our irrigation system capacity) and over $400 a month in water (municiple source) where we live in North Alabama... And our vinyard is only 1 acre!!! Surely this can't be a real number! Anyone willing to offer a more realistic number for approx gallons per vine per week?
At first glance, that does seem like an excessive amount. Especially running the math. One gallon = 231 cubic inches
27,000 gallons = 6.2 million ci One acre - 43,560 sq ft
6.2 million ci / 43,560 = 143 acre/inches or, about 20 acre inches per day....
On the other hand, when I was growing Thompson Seedless, I did drip irritation (pun deliberate) of about 2GPM for 90 minutes [per vine], or 180 gallons per day, or 1,260 gallons per week. I only had five vines so my water consumption was 6,300 gallons per week.
I gave up after four years because the yeild was terribly disappointing. Did I mention that I live in the northern end of California's share of the Great Mojave Desert?
Here's a good reading source for California Vineyards:
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From there you need to do a climatology comparison to northern Alabama. Evaporation is a major consideration in any case and a major factor in evaporation is transpiration. I'd guess the plants will surrender one-third to one-half of the water you give them into the atmosphere depending on the micro-climate humidity, temperature, and wind velocity. Good luck,
I am no climatology expert AND I do not know what variety(s) of grapes you are growing but I would think that after the possible exception of the first year, you do not need to irrigate at all in North Alabama.
Hi In South Australia ( the driest state in the driest habitated continent) a rule of thumb is about 25 ltrs a week or 40 ltrs every 14 days. Drippers are normally rated at 2.5 ltrs per hour. Water given as one treatment not as dribs and draps every day. We get only the occasional rain during summer. Day time temps up to 40 deg C. The real thing to do is either get local knowledge or irrigate by looking at the vines. They will show you when they are under water stress. Also do you want to water for maximum crop or maximum quality (least water)
Where did that 'rule of thumb' come from? Seems excessive to me. I have a small vineyard (about 200 vines) in northern california - hot, dry, where irrigation is a necessity. Typically, I start watering (drip lines, using 1 gph emitters) sometime in late May, and usually only water once or twice a week for a couple hours each. Meaning - apx. 4 gallons per vine per week. Sometimes more (hotter periods), sometimes less (early in the season, and from veraison on). Truth is, the vines will tell you; keep a close eye on the tendrils. If they are upright and reaching, the vine is well hydrated, if they start to droop, it needs some water. Then pay attention to the grapes for a season or three. You don't want to over-water and end up with big, beautiful - but poor wine-quality grapes. You want to end up with smaller berries, healthy; no 'shot-berries' or de-hydrated clusters, but with the least water needed to get them to that condition. As someone else said, I suspect you will need very little irrigation in Alabama.
Ric's advice seems reasonable. The information from Anton that a less frequent good soaking is better than a little every day is also correct. I am also in N. Alabama. We are currently in a very severe drought, already over 12 inches behind for this year. It was the driest January through March ever recorded. Last year was also very dry. My grapes started losing leaves in July - probably from a micronutrient deficiency magnified by the hot, dry weather. It seems that a "permanent" high pressure is blocking the gulf moisture. I have no way of knowing if this is a permanent climatological change or not, but the current conditions make some form of irrigation a necessity, especially with young vines.
I do not know what vines you are growing and what your season looks like exacly in Alabama, but I would venture to guess that save for the
1st year, you won't need much added water. Your numbers are high and, unless you are in the middle of a desert, this much water will probably prevent the roots of the plant from digging deep (something you want them to do).
Mother nature will most likely bring most of the water you need. Watch for early sign of dehydratation and intervene when you see them. After a couple of seasons, you'll get the feel of it. But again, it's better for them to suffer a little then to be over watered (unless producing X gallon of wine, regarless of quality, is of crtitical importance to you).
To get a precise answer to your question, you will need someone who knows the climate and the soil conditions where you are. It makes a lot of difference.
Depending on your vine spacing, you likely have 600 to 1000 vines per acre. Let's assume that you have 800 vines; that would be 33.75 gallons per vine per week. That much water might harm the vines. In the driest of climates, four to seven gallons per week per vine seems to be generally recommended.
I think your math is off. An acre is 43560 sq.ft. 27000 cu ft would be equivalent to 0.61 in/acre per week or about 2.5 in. of rain a month. As long as you get that (and in Alabama you probably do) then you would not need to irregate. During a dry season you might. But even so that would be expensive on city water witch is not designed for irregation. You need an alternative. Could you drill a well for irregation. Some places will allow you to.
The 27,000 gallon figure is about an acre-inch. 1" per week is a general recommendation for moisture for growing green plants. If Mother Nature doesn't supply it, the grower should.
Dunno about the requirements for fruit development.
Drip tape will cut the volume by 75%, but drips every 6 inches, which wastes water in this application.. You will drop the water volume requirement even more by using the emitter system, dropping a couple of emitters (for safety, in case one plugs!) near each stem.
Contact your local state agronomist for help with specifics on system design, emitter size and watering time. You might find it cost effective to consider drilling a well rather than using municipal sources.
Jack Wetmore, P. Ag.
snipped-for-privacy@testeng> > > ... All the data I can find calls for an excess of
USUALLY the problem in growing grapes, in the Eastern United States, is TOO MUCH water - natural rainwater.
The usual problem is EXCESSIVE growth. Unlike the drip irrigated vines in the arid or semi arid West whose growth can be CONTROLLED by drip irrigation, Vines in the Eastern US have to be hedged to keep growth within reasonable lengths.
Unlike a lot of other green plants, grape vine roots go down a LONG way. After the first year, most are able to find their own water. Most commercial growers around here (Northern Virginia and Maryland) do not even water 1st year plants.
As others have suggested, look at the tendrils. The vine will tell you when it is under stress from lack of moisture.
If I lived in Northern Alabama, I would be a LOT more concerned about fungus problems and Pierce's Disease.
I read an article from UC Davis that quoted 1 in water per weak and also received a growers guide from our vineyard supplier that basically said the same thing. I like your suggestion much better. Based on the responses I've received, it sounds like 4-6 gallons per vine per week from combination of natural rainfall and irrigation should get us good quality fruit without paying for some guy's retirement at the local waterworks...
We've had a very dry last 2 years in the Southeast US. Don't know if weather patterns have changed or if this is a long term blip. Either way, we need some irrigation these days. Don't know if the dry weather will last. We're taking the shotgun approach to grape growing. That is to say we're growing over 12 different varietals of Vinifera, French Hybrids, and Muscadine just to see which ones survice the Pierce's Disease. We're fools but having fun trying!
Thank for the input Anton. Do you get acceptable growth and disease resistence at those irrigation rates? Here in North Alabama, we normally have high humidity and resultant fungal diseases that can weaken or kill a vine if not healthy. I've been told irrigation helps the vine stay strong but we have to balance health with economics since it is after all only a hobby vineyard.
It's good to meet someone else growing grapes in North Alabama. We're attempting to growth about 12 different varietals in small quantities. We're trying some Hybrids, Vinifera, Muscadine, and brambles. In short, we're throwing Pierce's Disease and caution to the wind ;-) What are you growing? How large is your vineyard? How long have you been growing grapes in Alabama? We should talk! Would you be willing to pass along your contact info? If so, please send to snipped-for-privacy@phaseivxyz.com but remove the "xyz" from the email address (I do this to prevent bot spam).
You hit the nail on the head Paul! We're more worried about Pierce's Disease than anything else. Unfortunately, there's not much we can do about it as I understand. We've taken all practical measures to prevent but it's likely only a matter of time. We live here and have no choice so we're hoping Pierce's comes later not sooner so we can at least make a little wine before Doom's Day.
I don't think that there is a significant Pierce's Disease problem
*yet* until you get down toward Montgomery. If we don't get some cold winters, it may get here eventually. My main problem is Anthracnose on one particular variety (Marquis) and Japanese beetles.
It's interesting to find 2 other experimenters in North AL at the same time. Glad to know some others. I've got a few (33) vines of several hybrids that are a year old and looking pretty sick from the late frost. How have yours fared. My Chancellor is the worst hit. I don't know how they'll do through the summer.
Last year for their first year I watered at about 2 gal every 2 days if no rain and the vines fared pretty well.
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