Orchid Plant Care: Watering, Light and Reblooming

Most orchids sold as houseplants are moth orchids, Phalaenopsis, and they want indirect light, weekly watering at most, and a bark mix rather than soil. NC State Extension classifies Phalaenopsis as a low light orchid, best on an east windowsill, though well-shaded west and south windowsills also work, grown in a bark-based medium that drains freely, in clear plastic pots because the roots photosynthesise.

NC State's watering method is to water in the morning with tepid water, standing the plant in a sink and letting the water flow freely through; mature plants need this weekly, more in summer, and the potting mix should dry some between waterings.

NC State lists Phalaenopsis as non-toxic for cats, dogs and horses.

Two things bring a Phalaenopsis back into flower: enough light, and a run of cool nights.

Maryland says increasing light exposure is the most common fix, because insufficient light is the most common cause of not flowering. Iowa State Extension says the same and gives a way to read it: the leaves should be a medium, grassy green rather than dark green. Maryland's version of the same sign is that proper lighting produces light green foliage while insufficient light causes dark, stiff leaves.

On temperature, Iowa State says most species need several weeks of a ten to fifteen degree drop in night temperature, ideally down to 55 to 65 F. NC State says large-flowered varieties need a cool night chill of about 55 F for a week in autumn. Maryland suggests moving plants outdoors when evening temperatures dip into the fifties.

Maryland gives the cut precisely: prune yellowed or brown spikes back to about half an inch above the second node. NC State describes the same operation from the other direction - cut the flower stalk just above the first node below the faded flowers, and often, though not always, that node will produce a branch with more flowers.

The nodes are the small swellings along the spike above the foliage. Cutting above one leaves the plant the option of branching from it; removing the whole spike at the base sends its energy into leaves and roots instead.

NC State notes Phalaenopsis will flower repeatedly once a year with proper care, and that the flowers themselves can last four months or more.

Orchids are not potted in soil, and that changes how you water. NC State specifies a bark-based medium that provides excellent drainage, in clear plastic pots so the roots can photosynthesise, and waters in the mornings with tepid water by standing plants in a sink and letting the water flow freely; mature plants weekly, more in summer, with the mix drying some between waterings.

Maryland's method is three or four drenches over a ten-minute period with warm water, no more often than once a week in typical home conditions, and gives a useful visual check: aerial roots turn from white or silver to pale green when they are properly hydrated.

Repotting has a deadline. Maryland says to replace the bark mix every one to two years before it breaks down; NC State says approximately every two years, after the blooms fade.

NC State's feeding rate is a balanced fertiliser twice monthly at half strength, or weekly at quarter strength. Maryland says to fertilise actively growing and flowering plants every third or fourth watering with a commercial orchid fertiliser, and to skip feeding in winter when temperatures are cooler and light is lower. Iowa State's phrasing for the growing season is weakly, weekly.

On humidity, NC State describes Phalaenopsis as preferring warm, humid, damp but not soggy conditions, and Maryland notes that misting alone is not enough indoors. Penn State Extension is blunter: misting raises humidity only until the water evaporates, and grouping plants or running a humidifier is what actually works.

• Yellowing leaves. The lowest leaf yellowing and dropping as a new one opens is ordinary ageing. Widespread yellowing usually follows a wet medium; NC State notes the mix should dry some between waterings and Maryland caps watering at once a week.
• Wrinkled or shrivelled leaves. NC State says this is a sign the leaves are not getting enough water. Maryland attributes wrinkled leaves to low humidity and insufficient water. Check the roots before adding water - rotted roots cannot absorb it.
• Bud blast, buds dropping before they open. NC State attributes it to changes in temperature, humidity, moisture, fertiliser or location.
• No flowers. Maryland calls insufficient light the most common cause.
• Pests and disease. NC State lists greenhouse thrips, hemispherical scale, boisduval scale and mealybugs, plus botrytis blight.

NC State lists Phalaenopsis as non-toxic for cats, dogs and horses. That covers moth orchids specifically, which is what almost every supermarket and garden centre orchid is.

Non-toxic means poisoning is not expected. It does not make the plant edible, and an animal that eats a quantity of any plant material can vomit or have loose stools.

If you have an orchid that is not a Phalaenopsis, check it separately rather than assuming the whole family is listed the same way.

If a pet is unwell after chewing a plant, call your veterinarian or the ASPCA Animal Poison Control Center on (888) 426-4435; for a person, Poison Control on 1-800-222-1222. Our orchid pet safety page has the listing.

The US Botanic Garden gives a quick way to judge whether a window is bright enough: hold your hand about six inches above the orchid and look at the shadow on the leaves. A faint shadow means the spot suits low-light orchids, such as the moth orchids sold in most shops; a strong, distinct shadow means there is enough sun for high-light orchids.

The American Orchid Society's window advice matches: south- and east-facing windows work best, a west window may be too hot, and a north window is usually not bright enough. If a moth orchid in a faint-shadow spot still refuses to flower, the AOS names insufficient light as the most common cause of failure to rebloom.

First, decide what kind of orchid you have. The American Orchid Society notes that only Phalaenopsis, the moth orchid, reblooms from old flower spikes; on other orchids a spent spike will not flower again.

For a moth orchid you have two choices:

• Leave the spike and watch it. University of Maryland Extension says Phalaenopsis tends to form new flowering branches along old spikes, so watch the old spike for new buds after the flowers fall.
• Cut it back. Once the spike yellows or browns, Maryland says to cut it to about half an inch above the second node.

Then use the rest period. Maryland says to replace the potting medium every one to two years before it breaks down; NC State Extension says about every two years, after blooms have faded or as new leaves appear. The weeks after flowering are the natural time to do it.

The flowers on a moth orchid last from about a month to four months, and the plant can flower again every year. The sources give different bloom lengths: University of Maryland Extension says at least a month or longer with proper care, Wikipedia's Phalaenopsis article says two to three months in the home, and NC State Extension says four months or more.

None of these sources puts a maximum age on the plant itself. NC State says Phalaenopsis will flower repeatedly once a year with proper care; large-flowered types need cooler autumn temperatures to set buds, while modern dwarf hybrids do not. A potted orchid that gets fresh medium every one to two years and enough light has no fixed lifespan in these sources - most are lost to overwatering, which the US Botanic Garden says kills far more orchids than drying out.

The US Botanic Garden's watering rule is to drench the pot thoroughly and let it drain completely, never leaving the plant standing in water, and to let most orchids dry out a bit between waterings. The American Orchid Society calls improper watering the number one reason orchids fail.

Two things the basic guides often leave out:

• A night-time drop. The US Botanic Garden says many orchids prefer cooler nights and suggests leaving a window cracked open at night so the temperature falls about 10 degrees. This is the same cue that helps large-flowered moth orchids set buds in autumn.
• Moving air. The American Orchid Society notes that good air circulation helps fend off many orchid problems. A room with some air movement is better than a closed, still corner.

On feeding, the AOS says regular feeding is essential and that growers recommend a balanced fertiliser such as 20-20-20 that includes trace elements.

The sections on the hand-shadow light test, care after the blooms fall, how long orchids last, and watering, night temperatures and air were added on 2026-09-25. Research and drafting were done with the help of AI, and every figure was checked line by line against the sources listed on this page.