WateringTimesWatering plan, $19
Vitis vinifera ssp. & cvs., WUCOLS IV

How often to water grapevines in California

In July in the Central Valley, established grapevines in loam need a deep watering about every 8 days: about 2.2 gallons each time for a plant 2 feet across, about 1.9 gallons a week. Grapevines send roots well below the surface and need water to reach that deeper soil. They grow shoots and fruit through the warm season, then lose their leaves for winter. Keep moisture steady enough to support the crop without leaving the trunk or crown in saturated ground.

VineRated for 6 of 6 zones

How often to water grapevines, month by month

Your city
Plant width
2 ft
Your soil

Type your city above and the days between waterings and the gallons appear here, worked out from your city's climate table. Or read the figures by climate zone further down.

Every month, on your water days. The personal plan prints this for grapevines and the rest of your yard, on the days your water supplier allows.Get the plan for $19

How this is worked out: established roots fill the top 1.5 feet of soil, and you water again when that soil has dried halfway. Loam soil holds about 1.5 inches of water per foot. Water the whole area the plant covers, and skip a watering after a good soaking rain.

Which soil do you have?

Dig down a few inches, take a handful of moist soil and squeeze it.

  • Sandy: gritty, falls apart when you open your hand, will not form a ball.
  • Loam: forms a soft ball that crumbles when you poke it.
  • Clay: forms a firm, sticky ball and squeezes out into a ribbon between thumb and finger.

Still not sure? Pick loam. Most garden beds sit between sand and clay.

How to measure plant width

A shrub with its width marked from one side to the other and the circle under it shaded blue

Measure across the plant, from the tips of the leaves on one side to the tips on the other.

Water the whole area the plant covers, shown in blue. The gallons here cover that area.

A wider plant means more gallons each watering, not more waterings. While it is young, measure again each spring.

How to tell it needs water

  • Soil dry 8 to 10 inches down beneath an established grapevine signals that it needs a deeper moisture check
  • Tendrils that stop extending and dry back can indicate thirst while shoots are growing
  • Basal leaves yellowing and dropping during fruit sizing can accompany a dry root zone
  • Rank shoots and dense foliage shading slow-coloring fruit can accompany excess irrigation
  • Split berries after a heavy late soaking can indicate a sharp moisture swing around ripening clusters

How to water it

  • Place drip emitters about a foot from each side of the trunk, keeping clusters and woody stems dry
  • Soak the top two feet of soil around established vines, then let the surface dry before watering again
  • Keep sprinkler water off ripening clusters to reduce bunch rot risk
  • Mulch grape roots with coarse wood chips, keeping trunks clear, and plant on a broad mound where drainage is poor
  • Add emitters and widen the watered strip as roots spread and the vine fills its trellis

Through the seasons

Keep a new grapevine root ball evenly moist through its first summer and widen coverage as roots spread. Established vines need deeper soakings while shoots grow in spring and berries size in summer. Keep checking as clusters ripen and after harvest, when leaves help rebuild reserves. The vine rests bare from leaf fall to budbreak and uses little water. Coastal and Central Valley winter rain can supply dormant roots; check both deserts through dry winter spells. WUCOLS rates grapevines low water on the south coast and moderate water in the other five climate zones.

In pots

A grapevine needs a large, deep container to give its spreading roots room and a reserve of moisture. Check the top few inches of mix often in California summer heat. Water when they dry, soaking until excess leaves the drainage holes, then empty the saucer. Avoid sharp swings between saturated and dry mix while fruit is developing. The vine loses leaves in winter and uses much less water, but keep checking so the root ball never dries completely.

1 Your climate zone six WUCOLS zones, each from its own reference city
2.67gal per sq ft in JulyModerate water use in the Central Valley zone
A year
17.11 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.761.52.33.00.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.761.52.33.00.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Grapevines: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.310.780.740.78
Feb0.530.650.320.870.930.93
Mar0.871.090.461.31.461.52
Apr1.181.520.561.611.891.95
May1.462.080.641.952.392.45
Jun1.612.480.692.292.852.79
Jul1.612.670.792.513.042.85
Aug1.492.390.742.332.792.6
Sep1.241.80.61.862.142.08
Oct0.871.180.461.331.461.49
Nov0.470.560.330.90.930.96
Dec0.310.340.260.680.650.68
Year1217.116.218.4121.2721.08

How this is worked out: the WUCOLS water rating for each zone times that zone’s climate for the month. A dash means WUCOLS does not rate the plant there. The figures are what the plant uses, before sprinkler losses.

Plants with the same water needs 16

Rated moderate water in the Central Valley, like grapevines. Plants that drink alike can share one valve and one schedule.

JasmineJasminum polyanthummoderate water, Central Valley2.67 gal/sq ft in JulyStar JasmineTrachelospermum jasminoides and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyHoneysuckleLonicera japonicamoderate water, Central Valley2.67 gal/sq ft in JulyIvyHedera helixmoderate water, Central Valley2.67 gal/sq ft in JulyClematisClematis & ssp., hybrids & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyEvergreen ClematisClematis armandiimoderate water, Central Valley2.67 gal/sq ft in JulyWinter CreeperEuonymus fortunei radicansmoderate water, Central Valley2.67 gal/sq ft in JulyArabian JasmineJasminum sambacmoderate water, Central Valley2.67 gal/sq ft in JulyHyacinth BeanLablab purpureus (Dolichos lablab)moderate water, Central Valley2.67 gal/sq ft in JulyTrumpet HoneysuckleLonicera sempervirensmoderate water, Central Valley2.67 gal/sq ft in JulyPink Trumpet VinePodranea ricasolianamoderate water, Central Valley2.67 gal/sq ft in JulyPotato VineSolanum laxum (jasminoides)moderate water, Central Valley2.67 gal/sq ft in JulyItalian ClematisClematis viticellamoderate water, Central Valley2.67 gal/sq ft in JulyHopsHumulus lupulusmoderate water, Central Valley2.67 gal/sq ft in JulyBoston IvyParthenocissus tricuspidatamoderate water, Central Valley2.67 gal/sq ft in JulyVirginia CreeperParthenocissus quinquefolia ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 9

Rated lower than grapevines in the Central Valley. Worth a look for a new bed or a lawn replacement.

BougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyWisteriaWisteria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyFlowering WoodbineLonicera periclymenumlow water, Central Valley1.07 gal/sq ft in JulyFleeceflowerFallopia baldschuanica (Polygonum aubertii)low water, Central Valley1.07 gal/sq ft in JulyCarolina JessamineGelsemium sempervirenslow water, Central Valley1.07 gal/sq ft in JulyCecile Brunner RoseRosa 'Cecile Brunner'low water, Central Valley1.07 gal/sq ft in JulyLady Banks RoseRosa banksiaelow water, Central Valley1.07 gal/sq ft in JulyRoger's Red GrapeVitis 'Roger's Red'low water, Central Valley1.07 gal/sq ft in JulyBlue Dawn Morning GloryIpomoea acuminatalow water, Central Valley1.07 gal/sq ft in July
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes grapevines, your sprinkler type and the month, and gives the minutes per water day for that supplier's schedule. Or put it in a zone of the personal watering plan and get all twelve months printed.

Questions people ask

How often should I water grapevines in summer?

In July, established grapevines in loam need a deep watering about every 8 days in the Central Valley, about every 27 days on the south coast and about every 9 days in the South Inland zone. Sandy soil holds less water, so waterings come closer together. Clay stretches them. Check the soil before each watering and skip one after a soaking rain.

How much water do grapevines need per day?

In July in the Central Valley, established grapevines need about 0.3 gallons a day for a plant 2 feet across and about 1.1 gallons a day for a plant 4 feet across. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for grapevines change across California?

Yes. WUCOLS rates grapevines separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, moderate water in the Central Valley zone, low water in the South Coastal zone, moderate water in the South Inland zone, moderate water in the High and Intermediate Desert zone, moderate water in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

How do I water a newly planted grapevine?

Feel the nursery root ball separately from nearby ground. It can be dry while the surrounding bed is still damp. Extend emitter coverage during establishment instead of waiting for the vine to fill the trellis.

Can you overwater grapevines?

Yes. Persistent saturation can rot roots, particularly in heavy clay. Check below the surface before another soak, and keep water away from the crown.

Should I stop watering grapes before harvest?

Do not shut irrigation off simply because picking is near. Watch soil moisture as clusters color and avoid abrupt dry-to-wet swings. Stop reducing water if leaf edges scorch or leaves drop, exposing fruit to sunburn.

Which grapevines need winter moisture checks?

Pay particular attention to young vines during a warm, rainless winter and to pots sheltered from storms. Inspect the root ball before watering. Bare canes do not guarantee that the soil beneath them stayed moist.

How long should I run drip on grapevines?

Run drip until moisture reaches about two feet down along the grapevine's rooted row. Check between emitters, since trellis width does not define root spread.

More plant watering guides

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Sources