Phalaenopsis Orchids: Care, Roots, and Getting a Second Bloom

Phalaenopsis species grow attached to tree trunks and branches in the humid forests of Southeast Asia, with their roots clamped to bark and hanging in open air. They are not parasites — the tree is furniture, not food. Rain soaks them, and within hours the roots are dry again in moving air.

Every piece of orchid care that seems strange follows from that. The medium is chunky bark because roots need air around them. Watering is a thorough drenching followed by real drying. The pot is often clear, because the roots photosynthesise and are used to light. And nothing about the plant is adapted to sitting in wet compost, which is why an orchid potted like a houseplant dies within months.

The roots themselves are the giveaway. They are coated in velamen, a spongy white layer that absorbs water fast and then dries, protecting the living core inside. That coating is why a dry root looks silver and a wet one looks green — you are seeing water in the velamen, not the root itself.

Phalaenopsis wants bright indirect light — an east window is close to ideal, a north window works, and a south or west window needs a sheer curtain. Direct midday sun through glass burns the leaves in a single afternoon, leaving black or bleached patches that never heal.

The leaves tell you whether you have it right. A well-lit Phalaenopsis has mid-green, slightly olive foliage. Dark, glossy, deep green leaves look healthy to most people but actually indicate too little light — and a plant with them will keep growing leaves and never flower.

Normal room temperature suits it all year: roughly 18–26°C by day. The exception is autumn, which matters enormously and is covered below.

Humidity of 40–60% is comfortable, so a kitchen or bathroom windowsill is often the best spot in a home. It copes with less, but the flower buds are the first thing to suffer in very dry air — bud blast, where developing buds yellow and drop, is usually dry air, a draught, or a sudden move.

Water thoroughly, at the medium, until it pours out of the bottom of the pot — then let the whole thing drain and empty the outer cachepot completely. In a bark mix in an average room that works out at roughly every 7–10 days in summer and every 10–14 in winter, but check the roots rather than counting.

Do not use ice cubes. The practice is popular because it delivers a small measured amount, but tropical epiphyte roots are not adapted to cold, and it waters a fraction of the medium while leaving the rest dry.

Water in the morning and pour at the edge of the pot rather than over the plant. Water that collects in the crown — the tight point where the leaves meet — sits there, and in a cool room it rots the growing point. If you do splash it, blot it dry with kitchen paper.

Feed weakly and often: a balanced orchid fertiliser at quarter to half strength every second or third watering while the plant is in active growth, and roughly monthly in winter. Flush the pot with plain water every month or so to carry away accumulated salts, which bark holds poorly and roots resent.

This is where most people give up, usually after feeding the plant heavily and waiting. Phalaenopsis does not initiate a flower spike in response to nutrition. It initiates one in response to a sustained drop in night temperature, which in the wild signals the end of the growing season.

The practical recipe: from about September, give it night temperatures of roughly 13–16°C, with normal daytime warmth, for four to six weeks. A windowsill in an unheated room, a porch, or a conservatory does this naturally. A spike usually appears four to eight weeks later, emerging from the base of a leaf and looking distinctly different from a root — flatter, mitten-shaped at the tip, and growing upwards rather than outwards.

Keep the light bright throughout and keep feeding lightly. Once the spike appears, do not move the plant, and do not rotate it. Phalaenopsis orients its buds to the light source, and turning the pot mid-development produces a twisted spike or dropped buds.

Support the spike with a stake and a clip once it is 15 cm or so, clipping loosely below the developing buds. Expect eight to twelve weeks from spike to open flower, and then two to four months of bloom.

Bark breaks down. After 18 months to two years it has decayed into something that holds water like compost, and at that point the roots begin to suffocate and rot even if you have watered perfectly. Repotting an orchid is really about replacing the medium, not about pot size.

Do it every one to two years, ideally just after flowering when new roots are starting. Slide the plant out, crumble away all the old bark, and trim off every root that is brown, flat or hollow — a healthy root is firm and springy, whatever its colour.

Choose a pot barely larger than the root mass. Orchids flower better tight, and a large pot holds a volume of wet bark the roots never reach. Clear plastic pots make the root check easy and let the roots photosynthesise; a decorative outer pot hides them if you prefer.

Use a medium-grade orchid bark, optionally with some perlite or charcoal. Work it in around the roots with your fingers, tap the pot to settle it, and do not press it down hard — you are trying to leave air spaces, not eliminate them. Wait about a week before watering, so cut roots can seal.

Aerial roots that were never in the pot should stay out of it. They are doing their job in the air, and forcing them into bark usually rots them.