WateringTimesWatering plan, $19
Ceratonia siliqua, WUCOLS IV

How often to water carob in California

In July in the Central Valley, established carob in loam needs a deep watering about every 20 days: about 55 gallons each time under a 10 foot canopy, about 19 gallons a week. Carob is a slow-growing evergreen tree with a broad, rounded canopy of glossy, dark green leaflets that cast dense shade. Only female trees produce the long, dark seedpods carob is known for. Once established it is drought tolerant and needs only infrequent deep watering, though a young tree still needs help while its roots develop.

TreeRated for 5 of 6 zones

How often to water carob, month by month

Your city
Canopy width
10 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 carob 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 under the branches, 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 canopy width

A tree with its canopy width marked across the widest branches and the circle under it shaded blue

Measure across the branches, from the tips of the outer leaves on one side to the tips on the other. A tape works, or pace it out.

Water the whole circle under the branches, shown in blue. The gallons here cover that circle.

A wider canopy means more gallons each watering, not more waterings. While the tree is young, measure again each spring.

How to tell it needs water

  • A carob's canopy staying dull and sparse through summer, with dry soil at the drip line, calls for a deep soak
  • Pods shriveling or dropping early from a bearing female tree can follow a stretch of dry soil during fruit development
  • Height and canopy spread stalling for a season on an older tree often reflects its naturally slow pace rather than thirst
  • Yellowing leaves and soft bark near the base over soil that never dries can indicate root rot from overwatering
  • Leaflets curling tightly in the hottest afternoons on a young tree can indicate the root ball has dried out

How to water it

  • Soak the full spread of a young carob's roots with a slow trickle so water reaches deep into the soil
  • Let the surface soil dry out well between waterings once an established tree has settled in
  • Plant carob in ground that drains freely, since its roots fare poorly in standing water
  • Use drip emitters set wide of the trunk rather than aiming a hose at the base
  • Expand the watered circle outward each year as the broad canopy casts more shade

Through the seasons

A newly planted carob needs steady moisture while its deep taproot pushes down into the soil. Established trees stay evergreen year round and lean on that root system to carry them through summer heat with only occasional deep soaking. Flowering in spring and pod development through summer and fall are the months when a dry stretch matters most on a mature tree. Winter rain usually covers the cool season on the coast and in the valley. WUCOLS rates carob low water on the north-central coast, in the Central Valley, on the south coast and in South Inland. It rates moderate water in the low desert. WUCOLS marks it as not suited to the high desert.

In pots

A carob tree can spend its first few seasons in a large, sturdy container before its roots need open ground. Check the mix several inches down during California summer heat, since potting mix dries faster than garden soil. Water until it drains fully through the holes, then empty the saucer so the roots are not left sitting in it. In winter, water only once the mix has dried, since this evergreen's growth slows in cool weather.

1 Your climate zone six WUCOLS zones, each from its own reference city
1.07gal per sq ft in JulyLow water use in the Central Valley zone
A year
6.84 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.711.42.12.90.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.711.42.12.90.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

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

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.31–0.78
Feb0.210.260.320.35–0.93
Mar0.350.430.460.52–1.52
Apr0.470.610.560.64–1.95
May0.580.830.640.78–2.45
Jun0.640.990.690.92–2.79
Jul0.641.070.791–2.85
Aug0.60.950.740.93–2.6
Sep0.50.720.60.74–2.08
Oct0.350.470.460.53–1.49
Nov0.190.220.330.36–0.96
Dec0.120.140.260.27–0.68
Year4.86.846.27.37–21.08

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 low water in the Central Valley, like carob. Plants that drink alike can share one valve and one schedule.

Olive TreesOlea europaea ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyFig TreesFicus carica ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyCrape MyrtleLagerstroemia spp., hybrids & cvs.low water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyPomegranate TreesPunica granatumlow water, Central Valley1.07 gal/sq ft in JulyEucalyptusEucalyptus polyanthemoslow water, Central Valley1.07 gal/sq ft in JulyPine TreesPinus canariensislow water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyTexas Red OakQuercus buckleyilow water, Central Valley1.07 gal/sq ft in JulyPortuguese OakQuercus faginealow water, Central Valley1.07 gal/sq ft in JulySoapbark TreeQuillaja saponarialow water, Central Valley1.07 gal/sq ft in JulyNecklace TreeSophora affinislow water, Central Valley1.07 gal/sq ft in JulyBailey AcaciaAcacia baileyanalow water, Central Valley1.07 gal/sq ft in JulySilver WattleAcacia dealbatalow water, Central Valley1.07 gal/sq ft in JulyGreen WattleAcacia decurrenslow water, Central Valley1.07 gal/sq ft in JulySydney Golden WattleAcacia longifolialow 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 carob, 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 carob in summer?

In July, established carob in loam needs a deep watering about every 20 days in the Central Valley, about every 27 days on the south coast and about every 22 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 does carob need per day?

In July in the Central Valley, established carob needs about 2.7 gallons a day under a 10 foot canopy and about 11 gallons a day under a 20 foot canopy. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for carob change across California?

Yes. WUCOLS rates carob separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, low water in the South Coastal zone, low water in the South Inland zone, not suited to this region 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.

Why does my carob tree have no pods?

Most carob trees are either male or female, and only female trees bear the long pods, so a male tree never will. Some trees carry flowers with both parts. Extra water during the season helps a bearing tree produce quality pods.

Does carob need regular water once it is mature?

An established tree tolerates drought and needs only occasional deep watering. Extra irrigation supports better pods on a bearing carob.

Can carob grow in poor or rocky soil?

Yes, it tolerates most well-drained soils, including rocky or sandy ground. Slow-draining, waterlogged clay is the one condition to avoid most carefully. Drainage matters far more to this tree than fertility.

Why is my young carob tree growing so slowly?

Carob is naturally slow growing, especially in its first years in the ground. Steady moisture at the root ball supports this early growth without speeding it up much. Patience matters more than extra water for a young tree.

Is carob considered invasive in California?

It has naturalized in parts of Southern California after escaping cultivation. Established trees need little help once their roots run deep and wide. Check locally before planting it near wildland areas.

How do I tell a male carob tree from a female one?

Only flowering reveals the difference, since young trees of both sexes look alike. Female flowers develop into the long pods, while male trees never bear fruit. Many growers plant a known female for pods alongside a male for pollination.

More plant watering guides

Crape MyrtleWisteriaLantanaSalviaIrisesAloeSucculentsPomegranate Trees

Sources