Fruit & Perennials
Citrus (Orange/Lemon) Irrigation Guide
Citrus (Orange/Lemon) runs a 365-day season with water demand peaking at a crop coefficient of 0.65. On a hot mid-summer day (ETo of 6 mm), that is about 3.9 mm per day, or 27 mm (1.1 inches) per week. Every number on this page comes from the FAO-56 standard and is exactly what RainRule schedules with.
Season length
365 days
60 + 90 + 120 + 95 by stage
Root depth
1.2 m
≈ 3.9 ft at maturity
Peak daily use
3.9 mm
at mid-season, ETo 6 mm/day
Depletion threshold
50%
of available water before stress
Crop coefficient (Kc) through the season
Multiply any day's reference evapotranspiration (ETo) by the Kc below to get Citrus (Orange/Lemon)'s actual water use that day.
| Stage | Length | Kc | What's happening |
|---|---|---|---|
| Initial | 60 days | 0.65 | Establishment: bare soil dominates, low water use |
| Development | 90 days | 0.65 → 0.65 | Canopy closes; demand ramps day by day |
| Mid-season | 120 days | 0.65 | Full canopy: peak water use, most stress-sensitive |
| Late season | 95 days | 0.65 → 0.65 | Maturation: demand tapers toward harvest |
Refill points by soil type
Total available water (TAW) is what your soil holds across Citrus (Orange/Lemon)'s 1.2 m root zone. Irrigate when the running deficit crosses the refill point (RAW), 50% of TAW for Citrus (Orange/Lemon), so the crop never enters stress.
| Soil | Holds (TAW) | Irrigate at (RAW) | Days of peak use per refill |
|---|---|---|---|
| Sand | 84 mm | 42 mm | ~10 days |
| Sandy Loam | 144 mm | 72 mm | ~18 days |
| Loam | 180 mm | 90 mm | ~23 days |
| Silt Loam | 204 mm | 102 mm | ~26 days |
| Clay Loam | 192 mm | 96 mm | ~24 days |
| Clay | 168 mm | 84 mm | ~21 days |
Sandy soils hold the least water, so Citrus (Orange/Lemon) on sand needs small, frequent irrigations; clay holds the most and supports longer intervals with bigger applications.
Worked example: a peak-summer week
Take Citrus (Orange/Lemon) at mid-season on a week averaging an ETo of 6 mm/day:
- Daily crop use: 6 mm × Kc 0.65 = 3.9 mm/day
- Weekly demand: 3.9 × 7 = 27.3 mm (1.1 inches)
- On loam (90 mm refill point), a full profile lasts about 23 days with no rain before irrigation is due.
Real weeks aren't averages: ETo swings with heat waves and rain changes everything. That's the gap between a rule of thumb and a live schedule.
Related fruit & perennials guides
Get a live schedule for your citrus (orange/lemon) field
The free calculator combines these coefficients with your field's actual 7-day forecast. Or start a trial and let RainRule track your real water balance every hour.