How to grow orchids

Orchids are a massive family of plants consisting of hundreds of different species. They’re popular for their exquisite flowers which often last for months indoors.

Most indoor orchids are epiphytic or lithophytic, meaning they grow on trees or rocks in their natural habitat. Outdoor orchids are terrestrial meaning they grow in the ground and many can be successfully overwintered outdoors in the UK.

Read on to learn how to grow these exotic plants successfully in your home and garden!

How to grow orchids at home

Indoor orchids originate from tropical rainforests so require frost-free growing conditions. The most popular types which are widely available in garden centres are Phalaenopsis, Dendrobium, Cymbidium and Oncidium.

• Phalaenopsis – Known as the moth orchid, Phalaenopsis are one of the easiest orchids to grow and can be in flower for most of the year. Leaves are large, rounded and fleshy, forming a low-growing clump above which the slender flower stems rise.
• Dendrobium – Dendrobium orchids produce elongated stem-like pseudobulbs which resemble bamboo stems. Flower stems are produced at nodes along these ‘stems’.
• Cymbidium – Cymbidium orchids produce linear, grass-like leaves with long, slender flower stems which appear from the base of the plant.
• Oncidium – Oncidium orchids generally have wide, strap-shaped leaves and produce sprays of often yellow flowers, with prominent lips.

Temperature

Despite their tropical origins, indoor orchids vary in their temperature requirements due to the altitudes and environments in which they naturally grow. Cymbidium, Oncidium and Dendrobium orchids prefer cool temperatures and are best grown in a porch, conservatory or unheated room with a minimum night temperature of 10°C (50°F). When growing Phalaenopsis orchids, place them in a warm position at a minimum temperature of 18°C (64°F) – they are ideal for centrally heated rooms.

Watering

Orchids can be watered about once a week in the growing season but should never be left sitting in water. Rainwater is preferable but not essential. Simply water slowly and evenly from above, tipping out any excess water that collects in the saucer. Avoid watering the leaves and allowing water to collect in crevices, which can lead to rotting. Reduce watering during the winter months when plants become less active.

Feeding

Orchids are best fed with specialist orchid fertilisers, carefully following the instructions on the packet. Orchids need ‘flushing out’ quite often to prevent harmful accumulations of salts around the roots – simply water orchids with plain water once a month, without adding fertiliser. Stop feeding during the winter months when plants are less active.

Orchid	Temp	Light	Watering	Feeding
Phalaenopsis orchid	Phalaenopsis are warm-growing orchids. Minimum night temperatures should be 16°C (61°F), with day temperatures of 19-30°C (66-86°F). Avoid draughts.	Bright light all year round but avoid direct sunshine. Ensure good light levels in winter to encourage flowering.	Water freely between spring and autumn, taking care not to water the leaves. Mist Phalaenopsis orchids lightly in summer. Water sparingly in winter, keeping the foliage dry.	Phalaenopsis can be fed between spring and summer at every watering. Once a month, water only with plain water to flush out any accumulations of salt.
Dendrobium orchid	Dendrobium orchids generally prefer cooler conditions with a minimum night temperature of 10°C (50°F) and maximum daytime temperatures of 24°C (75°F).	From late spring to summer grow in partial shade. Admit full light from autumn to early spring .	Water freely from late spring through summer. Mist daily in summer. Keep plants dry throughout winter.	Feed Dendrobiums at every third watering from late spring through summer. Avoid fertilising in winter.
Cymbidium orchid	A cool-growing orchid preferring a minimum temperature of 10°C (50°F) and maximum temperature of 30°C (86°F). Can be kept outdoors during the summer. In winter keep at a temperature of 10-14°C (50-57°F). Cymbidium orchids need a distinct drop between day and night temperatures in the summer to flower well.	Place in bright light with shade from direct sunlight. Ensure good light in winter. If kept outdoors during summer place in a semi-shaded position, avoiding the intense midday sun.	Water moderately during spring and summer as required. Let the compost dry out a little between watering. In winter, water sparingly about once a fortnight.	Feed Cymbidiums at every third watering, diluting the fertiliser to half strength. Switch to a high potassium orchid fertiliser in summer, continuing to feed at every third watering. Avoid fertilising in winter.
Oncidium orchid	A cool to intermediate-growing orchid preferring a minimum temperature of 10°C (50°F) and maximum temperature of 30°C (86°F).	Bright light all year round but avoid direct sunshine. Ensure good light levels in winter.	Water freely between spring and autumn. Mist daily during the growing season. Water sparingly in winter.	Feed Oncidiums at every third watering between spring and autumn, diluting the fertiliser to half strength. Avoid fertilising in winter.

Flowering

Many orchids need a winter rest period to flower successfully, where feeding and watering are stopped or reduced, and plants are kept at cooler temperatures. See the table above for more details. Each orchid differs in the care it requires while flowering – see below for how to care for orchids in flower.

• Phalaenopsis – Tie in flower stems to a support as they grow, such as a thin stake. Once flowers start to fade, prune to a lower node on the flowering stem to encourage branching and more flowers to be produced.
• Dendrobium – Dendrobium orchids resent disturbance and flower best in small containers. Due to their tall growing habit this leaves them prone to tipping. Try growing them in heavy terracotta pots for stability and make sure to support flowering stems. After the flowers have dropped, cut the flowering stems back to the main pseudostem or just above the first set of leaves, depending on which type you are growing.
• Cymbidium – To prevent flower bud drop, keep Cymbidium orchids in cool conditions as the flower spikes develop, at a temperature of no more than 15°C (59°F). Once the flowers have opened, plants can be moved back to a warmer position. Support the flower spikes and once flowers have faded, cut them back to their base.
• Oncidium – Support the flowering stems of Oncidium orchids. Once the flowers fade, cut back flowering stems as close to their base as possible.

Re-potting

Orchids can be re-potted after flowering – this is normally done every 2 or 3 years. Use a specialist orchid compost which has a high bark content. Remove as much of the old compost as possible before re-potting into only a slightly larger container – many orchids will flower better with restricted root growth. Re-plant orchids at the same level as they were in their previous pot, taking care not to bury any aerial roots. Dendrobium orchids resent disturbance and are best re-potted when they resume growth again in the spring.

Failure to flower

It’s commonly asked why orchids won’t bloom and the most common reason is the need for a rest period, or lower temperatures to help initiate flowering. Light levels are also important – orchids will be reluctant to flower in a shady position. During the winter months when the sun is at its weakest, orchids can be placed on south-facing windowsills to allow maximum light levels during these shorter days.

If you’ve got any tips or tricks for growing orchids, we’d love to hear them! Let us know if the comments below, or share them with our gardening community over on our Facebook page.