WateringTimesWatering plan, $19
Begonia & ssp. & cvs. (shade in the desert), WUCOLS IV

How often to water begonias in California

In July in the Central Valley, established begonias in loam need a deep watering about every 5 days: about 1.5 gallons each time for a plant 2 feet across, about 1.9 gallons a week. Begonias have soft leaves and juicy, brittle stems that need protection from hot sun and dry wind. Keep their shallow root zone evenly damp without leaving it soggy. A wilted plant needs a soil check: both dryness and a rotting stem base can leave leaves hanging.

PerennialRated for 5 of 6 zones

How often to water begonias, 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 begonias 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 foot 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 1 to 2 inches down beside a begonia signals that its shallow roots need water
  • Leaves still drooping in cool morning shade can indicate thirst when the bed is dry
  • Crisp leaf edges and dropped buds can follow dry soil or reflected heat, so check moisture before watering
  • Yellow lower leaves with a soft, dark stem base in wet soil can indicate crown rot

How to water it

  • Water around begonia crowns with drip or a slow hose, keeping leaves and flowers dry
  • Wet the top several inches of soil, where the shallow roots take up moisture
  • Choose filtered shade or morning light with afternoon shade to protect the soft foliage
  • Loosen heavy clay before planting and set crowns slightly high so water does not pool against stems
  • Spread thin mulch clear of the stems and widen the watered strip as clumps fill the bed

Through the seasons

Check new begonia root balls frequently through their first summer, then water established beds as the shallow soil dries. Demand rises in heat and dry wind. Tuberous types die back in fall; taper irrigation and keep lifted tubers dry. Wax types retain leaves in mild coastal winters, where rain can supply moisture. Shelter pots from frost and check desert plants during dry winter spells. WUCOLS rates begonias moderate water on the north-central coast, in the Central Valley, on the south coast, in South Inland and in the low desert. WUCOLS has not evaluated them for the high desert. The WUCOLS entry carries a shade note for the deserts.

In pots

Begonia baskets can need daily checks in California summer heat. Feel the mix an inch down and water when it is dry there. Pour slowly until excess leaves the drainage holes, then empty the saucer so the succulent stems never sit above stagnant water. Use a light mix containing bark or perlite rather than dense, sodden material. Move pots out of cold soaking rain in winter, shelter them from frost, and reduce water as growth slows.

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
0.711.42.12.90.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.711.42.12.90.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.78–0.78
Feb0.530.650.810.87–0.93
Mar0.871.091.151.3–1.52
Apr1.181.521.41.61–1.95
May1.462.081.611.95–2.45
Jun1.612.481.742.29–2.79
Jul1.612.671.982.51–2.85
Aug1.492.391.862.33–2.6
Sep1.241.81.491.86–2.08
Oct0.871.181.151.33–1.49
Nov0.470.560.840.9–0.96
Dec0.310.340.650.68–0.68
Year1217.1115.518.41–21.08

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 begonias. Plants that drink alike can share one valve and one schedule.

DahliasDahlia spp.moderate water, Central Valley2.67 gal/sq ft in JulyFernsNephrolepis cordifolia (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in JulyDayliliesHemerocallis spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyCalla LiliesZantedeschia aethiopica SHADE IN DESERTmoderate water, Central Valley2.67 gal/sq ft in JulySageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBicolor MonkshoodAconitum cammarummoderate water, Central Valley2.67 gal/sq ft in JulyGarden MonkshoodAconitum napellusmoderate water, Central Valley2.67 gal/sq ft in JulyCarpet BugleAjuga reptans (shade)moderate water, Central Valley2.67 gal/sq ft in JulySnowdrop WindflowerAnemone sylvestrismoderate water, Central Valley2.67 gal/sq ft in JulyMountain SandwortArenaria montanamoderate water, Central Valley2.67 gal/sq ft in JulySwamp MilkweedAsclepias incarnatamoderate water, Central Valley2.67 gal/sq ft in JulyOrange MilkweedAsclepias tuberosamoderate water, Central Valley2.67 gal/sq ft in JulyGreater MasterwortAstrantia majormoderate water, Central Valley2.67 gal/sq ft in JulyHardy BegoniaBegonia grandismoderate water, Central Valley2.67 gal/sq ft in JulyWax BegoniaBegonia semperflorensmoderate water, Central Valley2.67 gal/sq ft in JulyEnglish DaisyBellis perennismoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

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

AgapanthusAgapanthus orientalislow water, Central Valley1.07 gal/sq ft in JulyGeraniumsPelargonium x hortorum and cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyIrisesIris germanicalow water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyYarrowAchillea millefolium (non-native hybrids)low water, Central Valley1.07 gal/sq ft in JulyMountain AlyssumAlyssum montanumlow water, Central Valley1.07 gal/sq ft in JulySilver SageSalvia argentealow water, Central Valley1.07 gal/sq ft in JulyPurple MulleinVerbascum phoeniceumlow water, Central Valley1.07 gal/sq ft in JulySilvery YarrowAchillea clavennaelow water, Central Valley1.07 gal/sq ft in JulyFern Leaf YarrowAchillea filipendulinalow water, Central Valley1.07 gal/sq ft in JulyCalifornia Native YarrowAchillea millefolium (CA native cultivars)low water, Central Valley1.07 gal/sq ft in JulyWoolly YarrowAchillea tomentosalow water, Central Valley1.07 gal/sq ft in JulyPerennial HollyhockAlcea rosea cvs.low water, Central Valley1.07 gal/sq ft in JulyMountain Lady's MantleAlchemilla alpinalow 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 begonias, 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 begonias in summer?

In July, established begonias in loam need a deep watering about every 5 days in the Central Valley, about every 7 days on the south coast and about every 6 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 begonias need per day?

In July in the Central Valley, established begonias 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 begonias change across California?

Yes. WUCOLS rates begonias separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, moderate water in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, not evaluated 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 should I check begonias in hanging baskets?

Give tuberous begonias close attention during hot weather. Keep their baskets shaded and check the mix before the leaves collapse. Warm air around a hanging basket can dry it faster than a sheltered ground bed.

How do I water indoor begonias?

Weaker light and still air can slow drying indoors. Feel beneath the surface before deciding to water, even if the same plant needed more outdoors. An occasional thorough flush helps remove accumulated mineral salts from the mix.

Where should I plant begonias in the ground?

Choose a spot with morning light and afternoon shade, particularly inland. Beds beneath eaves or overhanging branches may miss rain, so check them during the wet season too.

How do I protect begonias in a heat wave?

Set baskets in deep shade out of dry wind, and check their mix more often while heat persists. Water beds early when the shallow soil needs it. Extra irrigation cannot reverse scorch on exposed leaves.

Why are my begonia leaves yellow and dropping?

Feel the soil and inspect the stem base before adding water. Wilting over wet ground with a soft base can indicate rot. Fall yellowing in a tuberous type can instead be normal dieback, when irrigation should taper.

More plant watering guides

Amur MapleFernleaf MapleBox ElderNorway MapleRed MapleChinese MapleBicolor MonkshoodGarden Monkshood

Sources