How often to water stevia in California
In July in the Central Valley, established stevia in loam needs a deep watering about every 3 days: about 1.5 gallons each time for a plant 2 feet across, about 3.0 gallons a week. Stevia, also called sweetleaf, is a tender perennial herb from the warm, humid tropics of Brazil and Paraguay, grown for intensely sweet leaves. It needs moist, rich, well drained soil and steady water through the growing season. Too much water rots its fine roots, though, and it cannot take frost.
How often to water stevia, month by month
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.
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.
How to tell it needs water
- Soil dry 1 inch down around the stems means stevia needs water
- Thin, papery leaves wilting by midday in summer sun signal a dry root zone
- Lower leaves yellowing and stems collapsing at the base over wet soil point to root rot from overwatering
- Fine webbing and pale, speckled leaves point to spider mites rather than a watering fault
- Weak, floppy stems are normal for stevia and are not a sign of thirst
How to water it
- Water at the base of each plant with drip or a gentle hose, wetting the soil about a foot deep
- Water again once the top inch dries, since stevia wants evenly moist soil
- Plant in rich, slightly acidic, sandy loam with good drainage
- Mulch lightly to hold moisture through hot summers, keeping the mulch off the stems
- Grow it in a raised bed or a container with drainage holes if your soil is heavy clay
Through the seasons
Plant stevia after the last frost and keep the soil evenly moist while it roots in. Leaves are ready to harvest about 90 days after planting, and they are at their best just as flowering begins in July and August. Pinching off flower buds helps the leaf flavor. Frost ends the season unless plants are moved indoors or covered. WUCOLS rates stevia high water in the Central Valley. WUCOLS marks it as not suited to the north-central coast. It has not been evaluated for South Inland, the south coast, the low desert or the high desert.
In pots
Stevia grows well in a container, which also lets you bring it indoors before frost. Use a rich, well-draining mix in a pot with holes. Check the mix daily in summer heat and water when the top inch is dry. Water until it runs out the bottom, then empty the saucer, because soggy mix rots the roots. Indoors over winter, give it bright light and water only when the top of the mix dries, since growth slows in the cool months.
- A year
- 27.38 gal per sq ft
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
Monthly water need by climate zone
Stevia: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | – | 0.64 | – | – | – | – |
| Feb | – | 1.04 | – | – | – | – |
| Mar | – | 1.74 | – | – | – | – |
| Apr | – | 2.43 | – | – | – | – |
| May | – | 3.32 | – | – | – | – |
| Jun | – | 3.97 | – | – | – | – |
| Jul | – | 4.27 | – | – | – | – |
| Aug | – | 3.82 | – | – | – | – |
| Sep | – | 2.88 | – | – | – | – |
| Oct | – | 1.88 | – | – | – | – |
| Nov | – | 0.89 | – | – | – | – |
| Dec | – | 0.55 | – | – | – | – |
| Year | – | 27.38 | – | – | – | – |
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 high water in the Central Valley, like stevia. Plants that drink alike can share one valve and one schedule.
Japanese Sweet FlagAcorus gramineushigh water, Central Valley4.27 gal/sq ft in July
Red GingerAlpinia purpuratahigh water, Central Valley4.27 gal/sq ft in July
Shell GingerAlpinia zerumbethigh water, Central Valley4.27 gal/sq ft in July
Siberian BuglossBrunnera macrophyllahigh water, Central Valley4.27 gal/sq ft in July
Marsh MarigoldCaltha palustrishigh water, Central Valley4.27 gal/sq ft in July
Umbrella Sedge and PapyrusCyperus spp. (CA native and non-native species)high water, Central Valley4.27 gal/sq ft in July
Umbrella PlantDarmera peltata (Peltiphyllum)high water, Central Valley4.27 gal/sq ft in July
FoxgloveDigitalis purpurea cvshigh water, Central Valley4.27 gal/sq ft in July
Leopard PlantFarfugium japonicum cvs. (Ligularia tussilaginea cvs.)high water, Central Valley4.27 gal/sq ft in July
Transvaal DaisyGerbera jamesonii & hybridshigh water, Central Valley4.27 gal/sq ft in July
Giant GunneraGunnera manicatahigh water, Central Valley4.27 gal/sq ft in July
White Ginger LilyHedychium coronariumhigh water, Central Valley4.27 gal/sq ft in July
Japanese IrisIris ensatahigh water, Central Valley4.27 gal/sq ft in July
RushJuncus aquatic spp. (native and non-native spp.)high water, Central Valley4.27 gal/sq ft in July
Cardinal FlowerLobelia cardinalis hybrids and cvs. (CA native and non-native spp.)high water, Central Valley4.27 gal/sq ft in July
BananaMusa spp. (shade in low desert)high water, Central Valley4.27 gal/sq ft in JulySimilar plants that need less water 16
Rated lower than stevia in the Central Valley. Worth a look for a new bed or a lawn replacement.
DahliasDahlia spp.moderate water, Central Valley2.67 gal/sq ft in July
FernsNephrolepis cordifolia (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in July
DayliliesHemerocallis spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in July
BegoniasBegonia & ssp. & cvs. (shade in the desert)moderate water, Central Valley2.67 gal/sq ft in July
Calla LiliesZantedeschia aethiopica SHADE IN DESERTmoderate water, Central Valley2.67 gal/sq ft in July
SageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in July
Bicolor MonkshoodAconitum cammarummoderate water, Central Valley2.67 gal/sq ft in July
Garden MonkshoodAconitum napellusmoderate water, Central Valley2.67 gal/sq ft in July
Carpet BugleAjuga reptans (shade)moderate water, Central Valley2.67 gal/sq ft in July
Snowdrop WindflowerAnemone sylvestrismoderate water, Central Valley2.67 gal/sq ft in July
Mountain SandwortArenaria montanamoderate water, Central Valley2.67 gal/sq ft in July
Swamp MilkweedAsclepias incarnatamoderate water, Central Valley2.67 gal/sq ft in July
Orange MilkweedAsclepias tuberosamoderate water, Central Valley2.67 gal/sq ft in July
Greater MasterwortAstrantia majormoderate water, Central Valley2.67 gal/sq ft in July
Hardy BegoniaBegonia grandismoderate water, Central Valley2.67 gal/sq ft in July
Wax BegoniaBegonia semperflorensmoderate water, Central Valley2.67 gal/sq ft in JulyTurn this into minutes on your water days
Every city page has a calculator that takes stevia, 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 much water does stevia need per day?
In July in the Central Valley, established stevia needs about 0.4 gallons a day for a plant 2 feet across and about 1.7 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 stevia change across California?
Yes. WUCOLS rates stevia separately for each of the six California climate zones: not suited to this region in the North-Central Coastal zone, high water in the Central Valley zone, not evaluated in the South Coastal zone, not evaluated in the South Inland zone, not evaluated in the High and Intermediate Desert zone, not evaluated in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.
When should I harvest stevia leaves?
Start about 90 days after planting, and take the main harvest just as flowering begins. Cut stems about 6 inches above the ground so they regrow. Dried leaves taste sweeter than fresh ones.
Should I pinch off stevia flowers?
Yes. Removing the flower buds helps keep the leaves sweet. Keep the soil evenly moist after pinching, as before.
Can stevia survive winter outdoors in California?
Only where frost is rare or absent. It is a tender perennial, so in colder spots grow it in a pot and bring it indoors before the first frost. Water an overwintering plant sparingly.
Why is my stevia wilting when the soil is wet?
Wilting in wet soil points to root rot from overwatering. Let the soil dry an inch down before the next watering, and improve drainage or move the plant to a raised bed.
How sweet are stevia leaves?
The leaves are reported to be many times sweeter than sugar, with no calories. Fresh leaves can flavor tea, and dried leaves are ground into a sweet powder.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Stevia rebaudiana, the University of California survey California agencies use for landscape plan reviewRead August 23, 2026 on wucols.ucdavis.edu
- Model Water Efficient Landscape Ordinance, adopted text and appendices, effective 2025-01-02 · monthly reference evapotranspiration per city, Appendix CRead August 23, 2026 on water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Water-Use-And-Efficiency/MWELO-Rulemaking/Final-MWELO-Text-and-Appendices_20250103.pdf
- UC Statewide IPM Program, irrigation scheduling using evapotranspirationRead September 30, 2026 on ipm.ucanr.edu/PMG/GARDEN/ENVIRON/evap.html
- Shaw and Pittenger, Landscape Irrigation System Evaluation and Management, UC Cooperative Extension, 2009Read September 30, 2026 on ucanr.edu/sites/default/files/2013-02/160836.pdf
- Pittenger, Water Management in Gardens and Landscapes, UC Riverside, 2017Read September 30, 2026 on ucanr.edu/sites/default/files/2017-03/258022.pdf