WateringTimesWatering plan, $19
Dryopteris filix-mas, WUCOLS IV

How often to water male fern in California

In July on the north-central coast, established male fern in loam needs a deep watering about every 9 days: about 1.5 gallons each time for a plant 2 feet across, about 1.1 gallons a week. Male fern is a woodland species with arching, deeply divided fronds that rise from stout, upright rhizomes. It prefers moist, humus rich soil in shade, though established plants can tolerate dry shade. Keep new plants well watered while they settle in, and check soil during California's dry season.

PerennialCalifornia nativeRated for 3 of 6 zones

How often to water male fern, month by month

Your city
Plant width
2 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 male fern 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 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.

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 plant width

A shrub with its width marked from one side to the other and the circle under it shaded blue

Measure across the plant, from the tips of the leaves on one side to the tips on the other.

Water the whole area the plant covers, shown in blue. The gallons here cover that area.

A wider plant means more gallons each watering, not more waterings. While it is young, measure again each spring.

How to tell it needs water

  • Soil dry an inch or two down at the base of the crown signals this fern needs water
  • Brown or curled fronds call for checking moisture around male fern's crown before changing irrigation
  • Damaged young fronds warrant checking exposure, since strong winds can harm this fern
  • Water standing around a declining male fern calls for a drainage check before another soak
  • Frond damage in a sunny position calls for checking soil moisture as well as exposure

How to water it

  • Water at the base of the crown and across the root zone rather than wetting the fronds in strong sun
  • Keep the soil consistently moist a few inches down without letting it turn soggy
  • Work compost or leaf mold into the planting area to hold moisture the way a woodland floor does
  • Mulch around the crown with leaf litter or bark, keeping it clear of the emerging fiddleheads
  • Extend watering outward gradually as the clump widens over several seasons

Through the seasons

Keep a newly planted male fern evenly moist through its first year while the crown and roots settle into shaded soil. Established plants can cope with dry shade, but check the root zone during California summer drought. Male fern is deciduous, so seasonal frond loss does not by itself call for extra irrigation. Coastal rain can refill shaded beds in the cool season, but check beneath mulch during dry spells. WUCOLS rates male fern moderate water on the north-central coast, the south coast and South Inland. It has not evaluated this fern for the Central Valley, the high desert or the low desert.

In pots

For a potted male fern, choose a shaded spot and a mix rich in organic matter. Check the top inch often in California summer heat, since even a shaded pot can dry out between waterings. Water until it runs through the drainage holes, then empty the saucer so the crown does not sit in standing water. Shelter the fronds from strong winds. In winter, water less often but never let the mix dry out completely.

1 Your climate zone six WUCOLS zones, each from its own reference city
Not ratedWUCOLS does not rate Male Fern for the Central Valley zone
A year
no figure
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses

WUCOLS lists Male Fern as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Male Fern: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37–0.780.78––
Feb0.53–0.810.87––
Mar0.87–1.151.3––
Apr1.18–1.41.61––
May1.46–1.611.95––
Jun1.61–1.742.29––
Jul1.61–1.982.51––
Aug1.49–1.862.33––
Sep1.24–1.491.86––
Oct0.87–1.151.33––
Nov0.47–0.840.9––
Dec0.31–0.650.68––
Year12–15.518.41––

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 not evaluated in the Central Valley, like male fern. Plants that drink alike can share one valve and one schedule.

Lilyleaf LadybellsAdenophora liliifolianot rated, Central Valleyno Central Valley ratingArnicaArnica montananot rated, Central Valleyno Central Valley ratingFrilly BergeniaBergenia ciliatanot rated, Central Valleyno Central Valley ratingCabbage on a StickBrighamia insignisnot rated, Central Valleyno Central Valley ratingBasket PlantCallisia fragransnot rated, Central Valleyno Central Valley ratingForest SedgeCarex sylvaticanot rated, Central Valleyno Central Valley ratingUmbrella DracaenaDianella ensifolianot rated, Central Valleyno Central Valley ratingRusty FoxgloveDigitalis ferrugineanot rated, Central Valleyno Central Valley ratingBig-Flowered FoxgloveDigitalis grandifloranot rated, Central Valleyno Central Valley ratingWoolly FoxgloveDigitalis lanatanot rated, Central Valleyno Central Valley ratingSunset FoxgloveDigitalis obscuranot rated, Central Valleyno Central Valley ratingAlpine Sea HollyEryngium alpinumnot rated, Central Valleyno Central Valley ratingPurple SpurgeEuphorbia dulcisnot rated, Central Valleyno Central Valley ratingQueen of the MeadowFilipendula ulmarianot rated, Central Valleyno Central Valley ratingDropwortFilipendula vulgaris (Filipendula hexapetala)not rated, Central Valleyno Central Valley ratingGentianGentiana scabra procumbensnot rated, Central Valleyno Central Valley rating
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes male 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 often should I water male fern in summer?

In July, established male fern in loam needs a deep watering about every 7 days on the south coast and about every 6 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 male fern need per day?

In July on the north-central coast, established male fern needs about 0.2 gallons a day for a plant 2 feet across and about 0.7 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 male fern change across California?

Yes. WUCOLS rates male fern separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, not evaluated in the Central Valley zone, moderate water in the South Coastal zone, moderate water 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.

Can male fern grow in full sun in California?

It can grow in full sun if supplied with plenty of moisture, although a shaded position suits its woodland habit. In a hot California garden, start with partial or full shade and check the soil through dry weather. Extra water should not leave the crown in standing water.

Why are my male fern fronds turning brown and crisp?

Inspect the soil and exposure before deciding why fronds have browned. Male fern prefers moisture and benefits from protection against strong winds. Remove dead or damaged fronds as needed, and adjust irrigation only after checking the root zone.

Does male fern need rich soil?

It prefers humus rich soil, though it can grow in a range of soil types. Incorporate compost or leaf mold when preparing a planting site. Check sandy soil carefully during dry weather instead of assuming it will hold enough moisture.

Can I divide an established male fern clump?

Established clumps can be divided in spring. Keep divisions evenly moist while they reroot, much like a newly planted fern. This is a good time to refresh tired soil with compost.

Why does my male fern wilt even though I water it often?

Check whether the soil actually stays moist a few inches down rather than just wet on the surface. Fast draining or sandy soil can dry out between waterings even with frequent light sprinkling. Working in compost and mulching the surface usually helps it hold moisture longer.

More plant watering guides

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Sources