How often to water hart's tongue fern in California
In July on the north-central coast, established hart's tongue fern in loam needs a deep watering about every 22 days: about 1.5 gallons each time for a plant 2 feet across, about 0.5 gallons a week. Hart's tongue fern is a small evergreen fern with leathery, strap-shaped fronds that are bright green and often wavy at the edges. It grows in shade in humus-rich soil and thrives among limestone or in alkaline ground. Sharp drainage matters as much as moisture, since roots that stay wet will rot.
How often to water hart's tongue fern, 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 under the clump means hart's tongue fern needs water
- Fronds that lose their shine and brown at the edges point to dry soil, too much sun, or both
- Fronds yellowing from the base around a soft, dark crown over soggy soil point to root rot
- Rows of brown lines on the frond undersides are spore cases, not a disease or a sign of thirst
- Scorched patches on fronds that catch afternoon sun call for more shade, not just more water
How to water it
- Water at the base of the clump, keeping the leathery fronds and the crown as dry as you can
- Wet the soil about a foot deep, then let the top inch dry before the next watering
- Plant in shade in humus-rich soil with excellent drainage, adding grit or a raised spot in heavy clay
- Tuck it among limestone rocks or into neutral to alkaline soil, where it grows best
- Mulch lightly with leaf mold to keep the roots cool, clearing it away from the crown
Through the seasons
Keep a new hart's tongue fern evenly moist while its roots spread from the nursery ball. Established clumps get by with less, as long as they sit in shade. This evergreen fern holds its fronds all year, so long dry summer spells are when it needs the closest watch. On the north-central coast, winter rain covers the cool months, and WUCOLS rates the fern low water there. It has not been evaluated for the Central Valley. The south coast, South Inland, the high desert and the low desert are all marked not suited.
In pots
Hart's tongue fern stays compact, so it suits a shaded pot or a rock garden trough. Use a humus-rich, gritty mix that drains fast. Check the mix an inch down every few days in warm weather, and water when it is dry there. Let water run out of the drainage holes, then empty the saucer, because a wet crown rots. Keep the pot in shade, out of hot afternoon sun. In winter, water lightly, since the evergreen fronds grow slowly then.
- A year
- no figure
- Reference
- Sacramento climate table
- Counts
- Plant need, before sprinkler losses
WUCOLS lists Hart's Tongue Fern as not evaluated for the Central Valley zone, so no monthly figure is computed here.
Monthly water need by climate zone
Hart's Tongue Fern: gallons per square foot per month, by WUCOLS climate zone
| Month | N. Coast | C. Valley | S. Coast | S. Inland | Hi Desert | Lo Desert |
|---|---|---|---|---|---|---|
| Jan | 0.15 | – | – | – | – | – |
| Feb | 0.21 | – | – | – | – | – |
| Mar | 0.35 | – | – | – | – | – |
| Apr | 0.47 | – | – | – | – | – |
| May | 0.58 | – | – | – | – | – |
| Jun | 0.64 | – | – | – | – | – |
| Jul | 0.64 | – | – | – | – | – |
| Aug | 0.6 | – | – | – | – | – |
| Sep | 0.5 | – | – | – | – | – |
| Oct | 0.35 | – | – | – | – | – |
| Nov | 0.19 | – | – | – | – | – |
| Dec | 0.12 | – | – | – | – | – |
| Year | 4.8 | – | – | – | – | – |
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 not evaluated in the Central Valley, like hart's tongue fern. Plants that drink alike can share one valve and one schedule.
Lilyleaf LadybellsAdenophora liliifolianot rated, Central Valleyno Central Valley rating
ArnicaArnica montananot rated, Central Valleyno Central Valley rating
Frilly BergeniaBergenia ciliatanot rated, Central Valleyno Central Valley rating
Cabbage on a StickBrighamia insignisnot rated, Central Valleyno Central Valley rating
Basket PlantCallisia fragransnot rated, Central Valleyno Central Valley rating
Forest SedgeCarex sylvaticanot rated, Central Valleyno Central Valley rating
Umbrella DracaenaDianella ensifolianot rated, Central Valleyno Central Valley rating
Rusty FoxgloveDigitalis ferrugineanot rated, Central Valleyno Central Valley rating
Big-Flowered FoxgloveDigitalis grandifloranot rated, Central Valleyno Central Valley rating
Woolly FoxgloveDigitalis lanatanot rated, Central Valleyno Central Valley rating
Sunset FoxgloveDigitalis obscuranot rated, Central Valleyno Central Valley rating
Male FernDryopteris filix-masnot rated, Central Valleyno Central Valley rating
Alpine Sea HollyEryngium alpinumnot rated, Central Valleyno Central Valley rating
Purple SpurgeEuphorbia dulcisnot rated, Central Valleyno Central Valley rating
Queen of the MeadowFilipendula ulmarianot rated, Central Valleyno Central Valley rating
DropwortFilipendula vulgaris (Filipendula hexapetala)not rated, Central Valleyno Central Valley ratingTurn this into minutes on your water days
Every city page has a calculator that takes hart's tongue fern, 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 hart's tongue fern need per day?
In July on the north-central coast, established hart's tongue fern needs about 0.1 gallons a day for a plant 2 feet across and about 0.3 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 hart's tongue fern change across California?
Yes. WUCOLS rates hart's tongue fern separately for each of the six California climate zones: low water in the North-Central Coastal zone, not evaluated in the Central Valley zone, not suited to this region in the South Coastal zone, not suited to this region 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 is it called hart's tongue fern?
The long, strap-shaped fronds were thought to resemble a deer's tongue, and a hart is a male deer. The shape sets it apart from lacy ferns.
Does hart's tongue fern need acidic soil?
No. It grows best in humus-rich, alkaline soil and does well among limestone rocks. Slightly acidic soil also works, as long as it drains well.
What are the brown stripes under the fronds?
They are rows of spore cases, a normal feature of this fern. They do not mean the plant is sick or thirsty.
Can hart's tongue fern grow in sun?
It needs part shade to full shade. Sun scorches the glossy fronds and dries the soil quickly, so move a struggling plant to a shadier spot.
Why are my fern's fronds rotting at the base?
Soggy soil around the crown leads to root rot. Improve drainage, keep the crown at soil level when replanting, and let the top inch dry before watering again.
More plant watering guides
Sources
- WUCOLS IV plant water use classification for Asplenium scolopendrium (Phyllitis scolopendrium), 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