WateringTimesWatering plan, $19
Pinus sylvestris, WUCOLS IV

How often to water Scotch pine in California

In July in the Central Valley, established Scotch pine in loam needs a deep watering about every 8 days: about 55 gallons each time under a 10 foot canopy, about 47 gallons a week. Scotch pine is a needled evergreen conifer known for orange-tinted upper bark and twisted blue-green needles carried in pairs. It tolerates a range of soils but performs best where drainage is fast and reliable. Established trees handle dry spells reasonably well, while wet, heavy ground puts their roots at risk.

TreeRated for 3 of 6 zones

How often to water Scotch pine, 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 Scotch pine 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

  • Ground that stays dry past a young pine's drip line calls for a deep soak
  • Needles turning dull gray-green and slightly limp can indicate a thirsty young tree
  • Sparse new candles in spring on an otherwise healthy tree are worth tracing back to recent soil dryness
  • Needles browning from the interior out while soil stays constantly wet can indicate root rot from overwatering
  • Some interior needle drop in fall is normal shedding and does not by itself indicate thirst

How to water it

  • Water a young Scotch pine over its root ball and just beyond, extending coverage as the canopy widens
  • Give the surface real time to dry once the tree has settled in
  • Plant in a freely draining site and avoid heavy clay that holds water around the roots
  • Favor a slow soak or drip line over light, frequent sprinkling near the trunk
  • Reduce irrigation frequency as roots reach deeper soil layers in later years

Through the seasons

A newly planted Scotch pine needs steady moisture while new roots spread into surrounding soil. This conifer is evergreen and keeps needles through the year, though some interior needles drop each fall. Established trees draw on soil moisture at depth and tolerate dry spells better than young ones. WUCOLS rates Scotch pine moderate water on the north-central coast, in the Central Valley and in South Inland. WUCOLS marks it as not suited to the south coast. WUCOLS marks it as not suited to the high desert. WUCOLS marks it as not suited to the low desert. Winter rain often covers the coast and valley, but check soil at depth during dry stretches.

In pots

A young Scotch pine can spend its first year or two in a tall container before it goes into the ground, since its roots dislike crowding. Check the mix a few inches down through California heat, watering once that layer feels dry rather than on a fixed routine. Let water drain fully so roots are not left standing in it, then empty the saucer. A container dries faster than open ground, especially in valley or inland sun. In winter, ease off and check the mix only now and then, since growth slows in cool weather.

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
0.671.32.02.70.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.671.32.02.70.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Scotch Pine: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.4–0.78––
Feb0.530.65–0.87––
Mar0.871.09–1.3––
Apr1.181.52–1.61––
May1.462.08–1.95––
Jun1.612.48–2.29––
Jul1.612.67–2.51––
Aug1.492.39–2.33––
Sep1.241.8–1.86––
Oct0.871.18–1.33––
Nov0.470.56–0.9––
Dec0.310.34–0.68––
Year1217.11–18.41––

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 Scotch pine. Plants that drink alike can share one valve and one schedule.

Citrus TreesCitrus spp.moderate water, Central Valley2.67 gal/sq ft in JulyJapanese MapleAcer palmatummoderate water, Central Valley2.67 gal/sq ft in JulyAvocado TreesPersea americanamoderate water, Central Valley2.67 gal/sq ft in JulyMagnolia TreesMagnolia grandiflora ssp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyPalm TreesSyagrus romanzoffiana (Arecastrum romanzoffianum)moderate water, Central Valley2.67 gal/sq ft in JulyApple TreesMalus spp. (edible) e.g, 'Anna' (low chill variety for low desert)moderate water, Central Valley2.67 gal/sq ft in JulyPeach TreesPrunus spp. ediblemoderate water, Central Valley2.67 gal/sq ft in JulyPersimmon TreesDiospyros kakimoderate water, Central Valley2.67 gal/sq ft in JulyAmur MapleAcer ginnalamoderate water, Central Valley2.67 gal/sq ft in JulyFernleaf MapleAcer japonicummoderate water, Central Valley2.67 gal/sq ft in JulyBox ElderAcer negundomoderate water, Central Valley2.67 gal/sq ft in JulyNorway MapleAcer platanoidesmoderate water, Central Valley2.67 gal/sq ft in JulyRed MapleAcer rubrummoderate water, Central Valley2.67 gal/sq ft in JulyChinese MapleAcer truncatummoderate water, Central Valley2.67 gal/sq ft in JulyRed BuckeyeAesculus paviamoderate water, Central Valley2.67 gal/sq ft in JulyRed HorsechestnutAesculus x carneamoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

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

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 Scotch pine, 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 Scotch pine in summer?

In July, established Scotch pine in loam needs a deep watering about every 8 days in the Central Valley 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 does Scotch pine need per day?

In July in the Central Valley, established Scotch pine needs about 6.8 gallons a day under a 10 foot canopy and about 27 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 Scotch pine change across California?

Yes. WUCOLS rates Scotch pine separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, moderate water in the Central Valley zone, not suited to this region in the South Coastal zone, moderate water in the South Inland zone, not suited to this region in the High and Intermediate Desert zone, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Why do the inner needles on my Scotch pine turn yellow and drop?

Interior needle drop each fall is a normal part of this conifer's growth cycle. Compare it with new growth at the branch tips, which should stay green. Widespread browning that includes new needles points to a different problem.

Can Scotch pine handle heavy clay soil?

Clay that stays wet after watering or rain raises the risk of root rot in this species. Building up the bed or planting on a slope helps where clay drains poorly. Checking soil at depth before each watering matters more in clay than in sandy ground.

How do I water a young Scotch pine after transplanting?

Soak the entire root ball and the soil just beyond its edge. Let the top few inches begin to dry before watering again. Widen the watered area gradually as new roots extend outward.

Does Scotch pine need less water once it matures?

An established tree with a deeper root system usually tolerates longer gaps between waterings than a young one. Watch for dull or limp needles as a sign it has gone too long without moisture. Soil that stays constantly wet is a bigger risk to a mature tree than mild dryness.

Why is my Scotch pine browning from the inside of the tree out?

Check whether the soil has stayed wet for extended periods, since that favors root rot in this species. Compare the pattern with normal fall needle drop at the branch interior. A tree with healthy new candles and browning only deep inside is less concerning.

More plant watering guides

Leopard's BaneBronze FennelRaywood AshVancouver Gold GenistaBaby's BreathCreeping Baby's BreathHenry St. John's WortAaron's Beard

Sources