As the nights draw in and frost settles on outdoor beds, a greenhouse can transform into a vibrant winter retreat bursting with blooms. With careful choice of plants, pots and timing, even the chilliest months can become a gardener’s delight.

Here’s your complete guide to the best winter flowers for a greenhouse — including how to pot and grow them, practical tips, and a simple care calendar to keep your greenhouse glowing until spring.

Why Grow Winter Flowers in a Greenhouse?

A greenhouse offers unique benefits during winter:

• Temperature control: Protect delicate blooms from frost and cold winds.
• Extended flowering season: Enjoy flowers that would struggle outdoors.
• Protection from pests and diseases: Reduce weather related stress that makes plants vulnerable.
• Personal enjoyment: A warm, colourful greenhouse provides a much needed retreat in winter.

Choosing winter-flowering plants specifically suited to greenhouse conditions ensures your space remains alive with colour, fragrance, and texture even on the darkest days.

Factors to Consider Before Choosing Winter Flowers

Before filling your greenhouse, consider:

1. Temperature: Does your greenhouse stay heated? Some flowers prefer cool conditions, while others need warmth.
2. Light: Winter days are short; supplement with grow lights if needed.
3. Humidity: Balance ventilation to prevent fungal diseases.
4. Space: Some plants spread, climb or need staking.
5. Maintenance: Choose plants suited to your commitment level.

With these in mind, let’s explore the best winter flowers to grow under glass.

1. Cyclamen (Cyclamen persicum)

2. Camellias (Camellia japonica & hybrids)

Potting & Growing:

• Large pots or half-barrels with ericaceous compost (acidic).
• Ensure good drainage and shelter from strong winter sun.
• Water with rainwater to keep soil acidic.

Care tip: Keep evenly moist; don’t let them dry out, especially when buds swell.

Flowering: December–March (variety-dependent).

3. Primulas & Polyanthus

Potting & Growing:

• Grow in trays, pots or raised greenhouse beds.
• Use moisture-retentive compost enriched with leaf mould.
• Space well to allow air flow.

Care tip: Pinch off faded blooms to encourage more flowers.

Flowering: Late December–April.

4. Paperwhite Narcissus (Narcissus papyraceus)

Potting & Growing:

• Plant bulbs shallowly in bowls filled with gravel or bulb compost.
• Keep in a cool place (around 10°C) until shoots appear, then bring to brighter light.

Care tip: Rotate pots for even growth; stake tall stems.

Flowering: December–February.

5. Orchids (especially Cymbidium)

Potting & Growing:

• Use clear orchid pots or deep plastic pots with orchid compost (bark-based).
• Repot every 2–3 years after flowering.

Care tip: Bright, indirect light; keep greenhouse 10–15°C. Mist occasionally.

Flowering: Typically December–March.

6. Christmas Rose (Helleborus niger)

7. Sweet Peas (Lathyrus odoratus)

Potting & Growing:

• Sow in deep root trainers or pots (October/November).
• Plant out in greenhouse borders or larger containers in late winter.

Care tip: Pinch out tips when seedlings have 3–4 pairs of leaves.

Flowering: February–April under glass

8. Schizanthus (Poor Man’s Orchid)

Potting & Growing:

• Sow in autumn in pots; use multi-purpose compost.
• Transplant into slightly larger pots as they grow.

Care tip: Needs good light but keep cool.

Flowering: Late winter to early spring.

9. Streptocarpus

10. Kalanchoe blossfeldiana

Potting & Growing:

• Small decorative pots; cactus/succulent compost.
• Bright, sunny shelf.

Care tip: Minimal watering; feed lightly when buds show.

Flowering: Mid-winter onwards.

Tips for a Winter Flower Greenhouse

Tip	What to Do
Heat wisely	Maintain minimum temps (e.g. 5–7°C for hardy types, 10–12°C for tender types like orchids).
Maximise light	Clean glass, prune back shading plants, add grow lights for short days.
Humidity control	Open vents on mild days; avoid excessive damp to prevent fungal diseases.
Water sparingly	Check compost before watering; winter plants need less.
Feed gently	Use low-strength liquid feed once flower buds appear, typically every 2–3 weeks (variety-dependent).
Plan succession	Start bulbs in batches; sow cool-season annuals in autumn for staggered blooms.
Good hygiene	Remove fallen leaves, deadhead, and sterilise tools to reduce disease risk.
Design for delight	Layer tall plants at back, use colourful pots, and add seating or fairy lights for winter enjoyment.

Greenhouse Design Ideas for Winter Colour

• Layered staging: Place taller camellias and orchids at the back, cyclamen and primulas at the front.
• Hanging baskets: Grow trailing winter-flowering pansies or ivy-leaved cyclamen.
• Feature plants: Place dramatic camellias or cymbidiums in decorative pots as focal points.
• Scented corners: Group paperwhites and sweet peas where you often walk past.

Extra Touches for a Winter Retreat

• Fairy lights or lanterns: Warm light enhances winter evenings.
• Seating area: Even a small bench transforms the greenhouse into a sanctuary.
• Herbs and greenery: Add rosemary, thyme or winter salads for fragrance and utility.
• Sculptures and decorative pots: Create focal points and add personality.

Winter Greenhouse Flower Care Calendar

Month	What to Do
October	Sow sweet peas & schizanthus. Repot camellias. Start first batch of paperwhite narcissus.
November	Sow more paperwhites every 2–3 weeks. Move cyclamen & primulas into final display positions.
December	Watch for first blooms. Feed lightly as buds develop. Remove yellow leaves & faded flowers.
January	Ventilate on mild days. Stake tall stems (e.g., paperwhites). Remove spent blooms.
February	Continue light feeding. Sow late cool-season annuals for spring colour. Repot orchids after bloom.
March	Increase watering as light improves. Prepare for outdoor planting of hardy varieties in April.

Tip: Check plants at least weekly for water needs, pests or signs of disease. Feed sparingly – winter flowers need less than summer growers.

Final Thoughts