Orchid Plant Care: How to Keep a Moth Orchid Blooming

Orchid plant care for the common moth orchid (Phalaenopsis) is simple once you stop treating it like a normal houseplant: grow it in bark or moss, water it thoroughly about once a week and let it drain, and keep it in bright indirect light near an east window. To get it to bloom again, give it a few weeks of cooler nights in fall.

The moth orchid sold at US grocery stores and home centers is almost always a Phalaenopsis hybrid. In the wild, phals are epiphytes: they cling to tree trunks in Southeast Asian forests with their roots exposed to air and rain. Every care rule follows from that. The American Orchid Society calls them one of the easiest orchids to grow at home, and with a few basics a phal flowers for months every year.

This page covers moth orchids. Cattleya, dendrobium and oncidium orchids need more light and different watering.

Moth orchid care at a glance

Light: read the leaves

The AOS describes phals as "low light" orchids — low for an orchid, which still means bright for a houseplant. They grow beautifully in an east window and can live in a south or west window behind a sheer curtain. Illinois Extension suggests roughly 12–36 inches from a south window.

The leaves are your light meter:

• Olive or medium green: right.
• Dark, deep green and floppy: too little light — the most common reason an orchid won't rebloom.
• Red-tinged or yellowish: too much light.
• White or tan patch with a sharp edge: sunburn through glass.

Once the plant is in bloom you can display it anywhere out of direct sun; move it back to the window afterward. In dark apartments, a full-spectrum LED 12 inches above the leaves for 12 hours a day works well.

Watering: the part most people get wrong

Phalaenopsis have no pseudobulbs to store water, so they shouldn't dry out completely — but their roots rot fast if they sit wet. How often to water depends on the medium. AOS guidance: in bark, about once a week; in moss, when the top feels dry. Summer heat speeds that up; winter slows it down. After a few waterings you can judge by the weight of the pot. If in doubt, wait a day.

How to water:

1. Water in the morning so leaves dry by night.
2. Run room-temperature water through the pot in the sink for about a minute, or soak the pot in a bowl for 10–15 minutes.
3. Let it drain completely. Never leave the pot standing in water.
4. Blot any water caught in the crown (where the leaves meet) with a paper towel — standing water there causes crown rot.

AOS advises against salt-softened water and distilled water; ordinary tap water, rainwater or filtered water is fine.

About ice cubes: the "three ice cubes a week" method, promoted by some growers of moss-potted grocery orchids, keeps plants alive because it limits the water. It doesn't flush salts or wet all the roots. Thorough watering plus good drainage is better. For more detail, see how to water an orchid.

Roots: what healthy looks like

A clear pot lets you see roots without unpotting. Healthy roots are firm: silvery-white when dry, bright green right after watering. Brown, mushy or flat papery roots are dead. Roots climbing out of the pot are normal aerial roots; leave them alone.

Temperature and humidity

AOS puts it simply: phals like the same temperatures we do — above 60°F at night and 70–80°F by day, with 95°F as the maximum. Clemson HGIC gives 60–85°F as the ideal range and warns against leaves touching cold glass. Keep orchids away from heating and AC vents and from drafty doors.

Phals prefer 50–70% humidity. Most US homes drop to 20–30% in winter with forced-air heat. A humidifier nearby or a pebble tray (pot above, not in, the water) helps; misting does little.

Clemson notes you can move orchids outdoors from spring to fall when nights stay above 55°F, in full shade.

Potting medium and repotting

Never pot an orchid in regular potting soil — it suffocates the roots. Use medium-grade orchid bark, sphagnum moss, or a bark mix with perlite and charcoal. Bark dries faster and suits heavy waterers; moss holds water and suits people who forget.

Clemson recommends repotting every 1–3 years, shortly after blooming and never while the plant is in flower. Bark breaks down into a soggy compost after 1–2 years, which is when roots start rotting.

1. Remove the plant and shake off all old medium.
2. Trim dead roots with sterilized scissors.
3. Choose a pot just big enough for the healthy roots — orchids like to be snug. A clear plastic pot with plenty of holes is ideal.
4. Set the plant so the base of the lowest leaf sits at the surface, fill in with damp bark, and tap to settle.
5. Wait a few days before the first full watering.

See the step-by-step repotting an orchid guide, and our general repotting page.

Fertilizer

Clemson recommends a balanced orchid fertilizer such as 10-10-10 from mid-spring through early fall. Many growers follow the "weakly, weekly" approach: quarter-strength at most waterings, with plain water once a month to flush salts. Cut back in winter. Urea-free formulas are often recommended for bark mixes.

How to make an orchid rebloom

Healthy phals rebloom every year, usually in late winter or spring. The trigger is temperature. Illinois Extension lists nights of 55–65°F with days of 70–80°F, and a 10–15°F day-night difference, for several weeks before a spike appears. In a US home that means:

1. In September–October, put the orchid in a bright window in a cool room, or near (not touching) the glass, where nights drop into the 55–65°F range.
2. Keep that up for 3–6 weeks. Keep watering and feeding normally.
3. Watch for a new spike: a flattened, mitten-shaped green tip emerging between leaves (a root is round and silvery).
4. Once it appears, return to normal temperatures and don't move or rotate the plant while buds form — buds drop from changes in position, drafts and ethylene from ripening fruit.

After flowering, what to cut: Clemson suggests pruning the spike down to the leaves; the plant then flowers on a strong new spike within a year. Alternatively, cut a still-green spike just above the second node below the first flower — it often branches and blooms again in 8–12 weeks, though with fewer flowers. A brown spike always gets cut at the base.

Choosing a healthy orchid at the store

Most moth orchids are bought in bloom, so a good start matters more than with most plants:

• Leaves: 3–6 firm, glossy leaves with no wrinkles, black spots or soft bases.
• Roots: through a clear pot you should see plump silver or green roots. Brown, mushy roots and a sour smell mean the plant has been kept wet in the store.
• Flowers: choose a spike with several unopened buds at the tip; you'll get the longest display.
• Medium: many grocery orchids come packed in a dense plug of moss inside a sleeve pot. It holds water for a long time, so water less often than you would for bark, and plan to repot into bark once flowering ends.
• Moving it home: in cold months, wrap the plant for the trip to the car — a few minutes at freezing temperatures can blast the buds.

Why grocery-store orchids die

Most orchids that die in their first year are drowned. The decorative pot without drainage collects water, the moss plug stays soggy, and the roots rot within weeks while the flowers still look fine. By the time leaves go limp, few roots are left. The fix is simple: take the plastic grower pot out of the decorative pot to water, let it drain fully, and put it back only when it stops dripping.

The second cause is darkness. An orchid on a coffee table across the room can look perfect for 3 months on stored energy, then never flower again. Return it to a window when the flowers fall.

Propagation

Moth orchids are slow to propagate at home. The practical method is a keiki — a baby plant that sometimes forms on a flower spike. Once it has 2–3 leaves and roots 2–3 inches long, cut it off with a piece of spike and pot it in moss. Details are in orchid propagation.

Are orchids toxic to pets?

No. The ASPCA lists Phalaenopsis orchids as non-toxic to dogs, cats and horses. Store plants may carry pesticide residue, so it's still sensible to keep cats from chewing new arrivals. That makes moth orchids a good choice for pet-safe plants and flowering houseplants.

Pests

Watch for mealybugs in leaf joints and on roots, and scale as hard brown bumps on leaves; both leave sticky honeydew. Inspect leaf undersides when you water. Spider mites can appear in very dry air.

Similar plants

If you enjoy a moth orchid, try anthurium for long-lasting colored spathes, an African violet for steady flowers on a sill, or a bromeliad — another epiphyte that grows in airy mix. For the basics behind all of them, see houseplant care basics.