25 Unusual and Exotic Things to Grow in a Greenhouse
Your Complete Guide to Extraordinary Plants
Key Takeaways
Quick Guide for Busy Gardeners:
- Best for beginners: Cucamelons, loofah gourds, and passionflower
- Highest impact: Pineapples, vanilla orchids, and carnivorous plants
- Year-round producers: Tea plants, microgreens, and dwarf citrus trees
- Space-efficient choices: Vertical climbing beans, wall-mounted air plants
- Winter specialities: Forced bulbs, cold-tolerant succulents, and winter herbs
Your greenhouse can grow so much more than tomatoes and lettuce. From fruit that looks like tiny watermelons to plants that eat insects, these 25 unusual options will surprise visitors and give you harvests you can't buy in shops. Here's everything you need to know about growing exotic plants in UK greenhouses.
Why Grow Unusual Plants in Your Greenhouse?
Growing exotic plants in your greenhouse has some real benefits:
You'll create more biodiversity which helps your whole growing space stay healthy. Unique harvests give you ingredients that shops simply don't sell. Year-round interest keeps your greenhouse productive and beautiful through all seasons, while conversation starters make your greenhouse the most interesting place visitors want to see.
Plus, if you do want to sell any surplus, unusual plants often fetch much better prices than standard crops.
Getting Your Greenhouse Ready for Exotic Plants
Before we look at our list of 25 unusual plants, you'll want to make sure your greenhouse can handle different growing needs:
Temperature Control: You'll need both heating and ventilation to keep temperatures steady between 10-30°C. Most exotic plants hate sudden temperature swings.
Humidity Management: Automatic misting systems or humidity trays help maintain 60-80% relative humidity for tropical plants. A digital hygrometer will tell you exactly what's happening.
Better Lighting: LED grow lights help during UK winters and support light-hungry exotics. Position them 12-24 inches above plants (closer for weaker lights, further for stronger ones).
Water Quality: Many exotic plants prefer rainwater or filtered water over hard tap water. You might want to set up collection systems or use filters.
The Complete List: 25 Unusual Greenhouse Plants
1. Cucamelons (Mouse Melons)
Scientific Name: Melothria scabra
Difficulty Level: Beginner
Growing Season: April to October
These small, grape-sized fruits (also called mouse melons) look like miniature watermelons and taste refreshing with a slightly tangy kick. Cucamelons climb happily on supports and give you loads of fruit all summer long.
Growing Tips: Plant seeds in late April in small greenhouses after the last frost. Give them sturdy trellises as vines can reach 3 metres. Pick fruits when they're marble-sized for the best flavour.
Culinary Uses: These miniature fruits work brilliantly in gin and tonics, add crunch to summer salads, or pickle beautifully with dill and garlic for unique cocktail garnishes.
2. Loofah Gourds (Natural Sponges)
Scientific Name: Luffa cylindrica
Difficulty Level: Intermediate
Growing Season: May to October
The natural sponge is actually a vegetable - who knew? It's related to cucumbers and squashes. You can grow it in a greenhouse and eat the young fruit like squash. Let mature fruits dry on the vine and you'll have bathroom sponges.
Growing Tips: Start seeds indoors in March for moving to 6x4 greenhouses in May. These are vigorous climbers that need strong supports and steady moisture while fruits develop.
3. Tea Plants (Camellia sinensis)
Scientific Name: Camellia sinensis
Difficulty Level: Intermediate
Growing Season: Year-round
Once they get going, tea plants love the warm, sunny conditions a greenhouse gives them. Pick young leaves for making your own black, green, or white teas.
Growing Tips: Keep soil slightly acidic (pH 6.0-6.5) and don't let it dry out. Young plants take 3-4 years before you can harvest, but they'll keep producing for decades if you look after them.
4. Tropical Passionflower
Scientific Name: Passiflora species
Difficulty Level: Intermediate
Growing Season: April to October
Some passionflower varieties can handle UK outdoor conditions, but the really stunning tropical ones need greenhouse protection to do well. Their intricate flowers look like something from another planet.
Growing Tips: Give them alkaline, well-draining soil and strong climbing supports. Train the vines regularly so they don't tangle up and block flowers.
Symbolic Beauty: Spanish missionaries named passionflower for its resemblance to the Crucifixion - the corona representing the crown of thorns, five stamens for Christ's wounds, and three styles for the nails. Train multiple varieties on decorative bamboo or copper pipe trellises to create living artwork.
5. Pineapples
Scientific Name: Ananas comosus
Difficulty Level: Advanced
Growing Season: Year-round
You can actually grow pineapples in greenhouses, and they'll get bigger than if you grow them in pots. Starting from shop-bought crowns, pineapples take 18-24 months to fruit but make amazing focal points.
Growing Tips: Plant crowns in well-draining, slightly acidic compost. Keep temperatures above 18°C and give them bright light all year for the best growth.
Cultural Heritage: In 18th-century Britain, pineapples were such powerful status symbols that wealthy families rented them for dinner parties as centrepìeces, returning them uneaten the next day. Growing your own continues this tradition of horticultural prestige.
6. Vanilla Orchids
Scientific Name: Vanilla planifolia
Difficulty Level: Expert
Growing Season: Year-round
Vanilla is a climbing orchid that thrives in tropical conditions. So if you keep your greenhouse moist and warm, you can enjoy the challenge of growing vanilla. Hand-pollination is required for pod production.
Growing Tips: Maintain 85% humidity and temperatures between 18-29°C. Provide climbing supports and be patient - flowering begins after 2-3 years of growth.
Historical Significance: Vanilla was considered sacred by the Aztecs, who believed it was a gift from the gods. Only royalty were permitted to enjoy chocolate flavoured with vanilla beans, making your greenhouse vanilla truly regal.
7. Wasabi (Japanese Horseradish)
Scientific Name: Wasabia japonica
Difficulty Level: Advanced
Growing Season: Year-round
This delicious root, sometimes known as Japanese horseradish, gives a delightful flavour-kick to your cooking. It will grow well in temperatures of 8-20 C, in cool but humid environments and out of direct sunlight.
Growing Tips: Grow in shadier greenhouse areas with consistent moisture and excellent drainage. Harvest rhizomes after 2 years for authentic wasabi paste.
Culinary Heritage: Authentic wasabi was so prized in feudal Japan that samurai guarded wasabi farms, and theft was punishable by death. The plant's antimicrobial properties made it essential for safe raw fish consumption.
8. Ginger Root
Scientific Name: Zingiber officinale
Difficulty Level: Beginner
Growing Season: March to October
Unlike vanilla, ginger is relatively easy to grow in your greenhouse. You can start with a root (technically a rhizome) straight from the supermarket, having chosen one with multiple "eyes" that can turn into shoots.
Growing Tips: Start with organic supermarket ginger, plant in shallow containers, and maintain warm, humid conditions for rapid growth.
Recipe Ideas: Fresh greenhouse ginger creates exceptional crystallized ginger, spicy ginger beer, or aromatic curry pastes that far exceed store-bought alternatives in potency and flavour.
9. Tomatillos
Scientific Name: Physalis philadelphica
Difficulty Level: Beginner
Growing Season: April to October
Tomatillos are a delicious savoury fruit related to the tomato, and native to Mexico. They make delicious sauces and salsas. Their papery husks make them distinctive and attractive plants.
Growing Tips: Plant multiple varieties for cross-pollination. Allow space for sprawling growth habit and harvest when fruits fill their husks completely.
Culinary Uses: Roast tomatillos with garlic and peppers for authentic salsa verde, or use raw in refreshing summer gazpacho with cucumber and herbs. Their tangy flavour brightens any Mexican-inspired dish.
10. Dragon Fruit Cactus
Scientific Name: Hylocereus undatus
Difficulty Level: Intermediate
Growing Season: Year-round
This exotic climbing cactus produces stunning white flowers that bloom at night, followed by vibrant pink or yellow fruits with distinctive scales.
Growing Tips: Provide strong climbing supports as mature plants can reach 6 metres. Maintain warm temperatures and good drainage while allowing soil to dry between waterings.
11. Celtuce (Stem Lettuce)
Scientific Name: Lactuca sativa var. asparagina
Difficulty Level: Beginner
Growing Season: March to November
Celtuce offers a unique twist on lettuce - while leaves are edible, the thick, crunchy stem is the prized harvest, providing asparagus-like flavour and texture.
Growing Tips: Sow successively every 3 weeks for continuous harvest. Allow plants to bolt for stem development, then harvest when stems reach pencil thickness.
Culinary Discovery: Celtuce stems can be stir-fried like asparagus, sliced raw into salads for crunch, or pickled in rice vinegar for an Asian-inspired condiment. The unusual texture bridges the gap between lettuce and celery.
12. Oca (New Zealand Yam)
Scientific Name: Oxalis tuberosa
Difficulty Level: Intermediate
Growing Season: March to November
This South American root vegetable produces colourful tubers in shades of red, purple, yellow, and white, offering a tangy, potato-like flavour.
Growing Tips: Plant tubers after last frost in raised beds within your greenhouse. Harvest after foliage dies back, leaving tubers in sun for several days to sweeten.
13. Salsify (Oyster Plant)
Scientific Name: Tragopogon porrifolius
Difficulty Level: Beginner
Growing Season: March to December
This unusual root vegetable develops distinctive purple flowers and produces long, white roots with a subtle oyster-like flavour that's prized by gourmet cooks.
Growing Tips: Sow seeds directly in deep containers as roots can extend 30cm. Harvest roots after first frost for best flavour, or leave flowers for ornamental seed heads.
14. Yardlong Beans (Snake Beans)
Scientific Name: Vigna unguiculata subsp. sesquipedalis
Difficulty Level: Beginner
Growing Season: May to October
These remarkable beans can grow up to 60cm long and provide vertical growing opportunities in compact greenhouse spaces.
Growing Tips: Harvest beans when young and tender at 30-45cm length for best eating quality.
Culinary Versatility: Young yardlong beans can be stir-fried whole, cut into segments for curries, or pickled for crunchy condiments. In Asian cuisine, they're often paired with fermented black beans and garlic for classic flavour combinations.
15. Carnivorous Plants Collection
Scientific Name: Various species
Difficulty Level: Intermediate
Growing Season: Year-round
If these spicy and tropical options don't tickle your fancy, maybe you should consider growing carnivorous plants in your greenhouse. These can be visually stunning and of never-ending interest to young people, so can be a great way to engage kids in gardening.
Popular Varieties: Venus flytraps (Dionaea muscipula), Pitcher plants (Sarracenia), Sundews (Drosera), and Cobra plants (Darlingtonia californica).
Growing Tips: Use rainwater or distilled water exclusively. Plant in sphagnum moss or specialized carnivorous plant compost. Maintain high humidity and bright light.
Display Ideas: Design miniature wetland scenes using shallow ceramic dishes filled with sphagnum moss. Add small decorative logs and stones to create prehistoric landscapes that fascinate children and adults alike.
16. Air Plants (Tillandsia)
Scientific Name: Tillandsia species
Difficulty Level: Beginner
Growing Season: Year-round
These fascinating epiphytes require no soil and create living art installations while purifying greenhouse air.
Growing Tips: Mount on driftwood or wire frames. Mist 2-3 times weekly and ensure good air circulation. Bright, indirect light produces best colouration.
Creative Displays: Mount tillandsia collections on driftwood sculptures or create floating displays using clear fishing line. Group different textures and colours for museum-quality presentations that transform your greenhouse into living art.
17. Ice Plants (Crystalline Flowers)
Scientific Name: Delosperma species
Difficulty Level: Beginner
Growing Season: Year-round
These drought-tolerant succulents produce jewel-like flowers and fascinating crystalline leaves that store water.
Growing Tips: Provide excellent drainage and intense light. Allow soil to dry completely between waterings. Perfect for greenhouse windowsills and hanging baskets.
18. Banana Plants
Scientific Name: Musa species
Difficulty Level: Intermediate
Growing Season: Year-round
Dwarf banana varieties can fruit in large greenhouse containers, bringing tropical ambiance and potential harvests.
Growing Tips: Choose dwarf cultivars like 'Super Dwarf Cavendish' for container growing. Maintain warm temperatures and high humidity for fruit production.
19. Coffee Plants
Scientific Name: Coffea arabica
Difficulty Level: Intermediate
Growing Season: Year-round
Growing your own coffee beans is possible in greenhouse conditions, with plants producing fragrant white flowers followed by red berries.
Growing Tips: Maintain consistent moisture and filtered light. Plants require 3-4 years to begin fruiting and prefer slightly acidic soil conditions.
Tea Traditions: Process fresh tea leaves by withering, rolling, and drying to create your own black tea, or steam briefly for homemade green tea with unparalleled freshness. Each processing method creates distinctly different flavours from the same plant.
Coffee Culture: Process your homegrown coffee beans by removing the pulp, fermenting, washing, and roasting for a truly artisanal coffee experience. Even small harvests create meaningful personal blends.
20. Stevia (Natural Sweetener)
Scientific Name: Stevia rebaudiana
Difficulty Level: Beginner
Growing Season: April to October
This natural sweetener plant produces leaves 30 times sweeter than sugar, offering a homegrown alternative to processed sweeteners.
Growing Tips: Pinch flowers to encourage leaf production. Harvest leaves before flowering for maximum sweetness concentration.
Natural Sweetening: Dry stevia leaves to create homemade natural sweetener for teas, or infuse vodka with fresh leaves for naturally sweet cocktail syrups. Fresh leaves can sweeten beverages without any processing.
21. Lemon Balm and Exotic Herbs
Scientific Name: Melissa officinalis and others
Difficulty Level: Beginner
Growing Season: Year-round
Beyond common herbs, grow exotic varieties like chocolate mint, pineapple sage, and Vietnamese coriander for unique culinary experiences.
Growing Tips: Succession plant herbs every 4 weeks for continuous harvest. Many exotic herbs prefer partial shade and consistent moisture.
22. Hardy Hibiscus
Scientific Name: Hibiscus rosa-sinensis
Difficulty Level: Beginner
Growing Season: Year-round
Chinese Hibiscus produces very large but delicate-looking flowers with ruffled and frilly petals and prominent stamens. Colours include red and magenta, but also pastel pink and mellow orange.
Growing Tips: Provide bright light and consistent moisture during growing season. Reduce watering in winter and maintain temperatures above 10°C.
Garden Artistry: Arrange different hibiscus varieties by colour progression - from pale yellows through deep oranges to vibrant reds - creating living rainbow displays that provide months of stunning blooms.
23. Exotic Melons
Scientific Name: Cucumis melo varieties
Difficulty Level: Intermediate
Growing Season: May to September
Greenhouses offer the ideal humid and warm environment for growing melons, which can be challenging to cultivate outdoors in the UK. Try unusual varieties like Armenian cucumber melons or Japanese crown melons.
Growing Tips: Provide strong supports for climbing varieties. Hand-pollinate flowers for reliable fruit set in enclosed greenhouse environments.
24. Miracle Berry
Scientific Name: Synsepalum dulcificum
Difficulty Level: Advanced
Growing Season: Year-round
This remarkable plant produces berries that temporarily alter taste perception, making sour foods taste sweet for up to an hour.
Growing Tips: Requires acidic soil (pH 4.5-5.5) and consistent warmth. Young plants take 3-4 years to fruit but are fascinating conversation pieces.
25. Sensitive Plant (Touch-Me-Not)
Scientific Name: Mimosa pudica
Difficulty Level: Beginner
Growing Season: Year-round
Possibly the shyest member of the plant kingdom, this plant has bright green pinnate leaves. Depending on how you touch them, all the pinnate leaves close inward in unison or opposing pairs close in succession.
Growing Tips: Maintain warm temperatures and bright light. Enjoy the fascinating leaf movement response to touch - perfect for engaging children in gardening.
Educational Wonder: Mimosa pudica is called "Lajjalu" in Sanskrit, meaning "shy one." Hindu traditions believe the plant teaches humility and sensitivity to our environment, making it perfect for mindful gardening practices.
Seasonal Growing Calendar
Spring (March-May)
- Start from seed: Cucamelons, loofah, tomatillos, celtuce, salsify
- Plant outdoors: Hardy herbs, oca tubers after last frost
- Propagate: Ginger rhizomes, banana plant divisions
Summer (June-August)
- Peak harvest: Cucamelons, young loofah, herbs, melons
- Maintenance: Train climbing plants, hand-pollinate melons
- Start: Late summer herbs, air plant displays
Autumn (September-November)
- Harvest: Mature ginger, oca tubers, dried loofah
- Prepare: Winter protection for tender perennials
- Plant: Spring flowering bulbs for forcing
Winter (December-February)
- Maintain: Tropical plants with supplemental heat and light
- Plan: Next year's exotic plant choices and greenhouse modifications
- Enjoy: Forced bulbs, winter herbs, preserved harvests
Making the Most of Your Space
Growing Upwards: Use your greenhouse height with climbing plants like yardlong beans, loofah, and passionflower. Put in sturdy supports that reach right up to the roof.
Succession Planting: Stagger sowings of quick-growing crops like herbs and celtuce every 3-4 weeks so you'll have fresh harvests all season long.
Mix and Match: Combine plants with different needs. Grow shade-loving wasabi under tall climbing beans, or stick air plants on unused wall spaces.
Moveable Containers: Wheeled plant stands let you move large container plants around for the best growing conditions as seasons change.
Winter Growing Ideas
Turn your greenhouse into a productive winter space with these cold-season options:
Forced Bulbs: Pre-cooled tulips, daffodils, and hyacinths give you colour during the darkest months. Plant in November for blooms from January to March.
Winter Herbs: Hardy varieties like winter savory, rosemary, and thyme keep producing when your garden beds are frozen solid.
Microgreens: Fast-growing shoots of exotic vegetables give you fresh nutrition in just 7-14 days. Try radish, beet, and sunflower varieties.
Cold-Frame Crops: Mâche (corn salad), winter purslane, and land cress do well in unheated greenhouse sections.
Creative Display Ideas and Cultural Connections
Turn your greenhouse into an experience that celebrates the fascinating stories behind your exotic plants:
Beautiful Display Ideas for Ornamental Plants
Passionflower Displays: Train different varieties on decorative bamboo or copper pipe frames to create living artwork. Mix purple Passiflora caerulea with red P. coccinea for stunning colour contrasts.
Air Plant Installations: Mount tillandsia collections on driftwood sculptures or create floating displays using clear fishing line. Group different textures and colours for displays that look like they belong in a museum.
Carnivorous Plant Bog Gardens: Design miniature wetland scenes using shallow ceramic dishes filled with sphagnum moss. Add small decorative logs and stones to create prehistoric landscapes.
Hibiscus Colour Themes: Arrange different hibiscus varieties by colour - from pale yellows through deep oranges to vibrant reds - creating living rainbow displays.
Recipe Ideas for Edible Exotics
Cucamelon Creations: These miniature fruits work brilliantly in gin and tonics, add crunch to summer salads, or pickle beautifully with dill and garlic for unique cocktail garnishes.
Ginger Innovations: Fresh greenhouse ginger makes exceptional crystallized ginger, spicy ginger beer, or aromatic curry pastes that beat anything you can buy.
Stevia Natural Sweets: Dry stevia leaves to make homemade natural sweetener for teas, or infuse vodka with fresh leaves for naturally sweet cocktail syrups.
Tomatillo Salsas: Roast tomatillos with garlic and peppers for authentic salsa verde, or use raw in refreshing summer gazpacho with cucumber and herbs.
Tea Plant Traditions: Process fresh tea leaves by withering, rolling, and drying to make your own black tea, or steam briefly for homemade green tea with unmatched freshness.
Historical and Cultural Facts
Pineapple Status Symbols: In 18th-century Britain, pineapples were so expensive that wealthy families rented them for dinner parties as centrepìeces, returning them uneaten the next day.
Vanilla's Royal Origins: Vanilla was sacred to the Aztecs, who believed it was a gift from the gods. Only royalty could enjoy chocolate flavoured with vanilla beans.
Sensitive Plant Spirituality: Mimosa pudica is called "Lajjalu" in Sanskrit, meaning "shy one." Hindu traditions say the plant teaches humility and sensitivity to our environment.
Wasabi's Samurai Connection: Authentic wasabi was so valuable in feudal Japan that samurai guarded wasabi farms, and theft could mean death. The plant's antimicrobial properties made it important for safe raw fish eating.
Passion Flower Symbolism: Spanish missionaries named passionflower for its resemblance to the Crucifixion - the corona representing the crown of thorns, five stamens for Christ's wounds, and three styles for the nails.
Common Problems and How to Fix Them
Pest Issues: Enclosed greenhouse spaces can harbor pests. Bring in beneficial insects like predatory mites and keep air moving well to prevent infestations.
Disease Prevention: Give plants enough space and avoid watering from above to prevent fungal diseases. Remove any affected plant bits straight away.
Climate Control: Automated systems work better than trying to manage temperature and humidity manually with lots of different plants.
Pollination: Many fruiting plants need hand-pollination in greenhouse spaces. Learn the right techniques for each crop type.
Advanced Growing Methods
Hydroponics: Soilless growing systems work really well for herbs, leafy greens, and smaller fruiting plants. Look at deep water culture or nutrient film technique setups.
Smart Planting: Strategic plant combinations improve growing conditions. Plant nitrogen-fixing beans near heavy-feeding crops like melons.
Grafting: Combine hardy rootstocks with exotic tops for better cold tolerance and disease resistance.
Season Extension: Use row covers, thermal mass, and extra heating to extend growing seasons for warm-weather crops.
Looking After Your Greenhouse All Year
Daily Jobs: Check temperature, humidity, and watering needs. Look for pest and disease signs during regular walks through your greenhouse.
Weekly Jobs: Harvest ready crops, train climbing plants, and adjust ventilation based on weather conditions.
Monthly Jobs: Apply fertilisers, prune overgrown plants, and clean greenhouse glass for maximum light.
Seasonal Jobs: Deep clean greenhouse structure, service heating systems, and plan crop rotations for better soil health.
Frequently Asked Questions
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What cannot be grown in a greenhouse?
Plants requiring cold stratification (many fruit trees), extremely large trees, and crops needing wind pollination struggle in greenhouse environments. Additionally, plants requiring specific pollinators not present in enclosed spaces may fail to fruit.
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What can I grow in a greenhouse all year round in the UK?
Year-round options include most herbs, leafy greens, dwarf citrus trees, air plants, succulents, and tropical houseplants. With supplemental heating, expand possibilities to include tender perennials like hibiscus and geraniums.
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What is the most profitable thing to grow in a greenhouse?
High-value crops like microgreens, specialty herbs (basil, coriander), tomatoes, and cut flowers typically offer best returns. Consider local market demand and your production capacity when choosing profitable crops.
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What grows fast in a greenhouse?
Rapid producers include microgreens (7-14 days), lettuce and other leafy greens (4-6 weeks), radishes (3-4 weeks), and most herbs (4-8 weeks from seed to harvest).
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What unusual things can I grow in a greenhouse in winter?
Winter options include forced bulbs, cold-hardy herbs, winter salads, sprouting vegetables, and tropical plants that can't survive UK winters outdoors. Heated greenhouses open up way more possibilities.
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How do I keep different plants happy in the same greenhouse?
Create different mini-climates using partial shade cloth, humidity trays, and smart plant positioning. Group plants with similar needs together and use portable heaters or fans for localized climate control.
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When should I start planning my unusual greenhouse crops?
Start planning in January-February for the upcoming growing season. Order seeds and specialist equipment early, as unusual varieties often sell out quickly. Think about what worked and what didn't from the previous year.
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How much space do I need for exotic greenhouse growing?
Even small lean-to greenhouses can fit several unusual crops through vertical growing and succession planting. Potting sheds give you extra storage for tools and supplies needed for diverse plant care.
Change your greenhouse from a simple growing space into an exotic paradise that produces unique harvests, amazes visitors, and gives you year-round gardening satisfaction. Start with easier options like cucamelons and herbs, then gradually add to your exotic plant collection as you get more experience and confidence.
Ready to start your exotic greenhouse journey? Pick 3-4 plants from this list that match your experience level and greenhouse size, then expand your collection as you master each new challenge.
