Top of The Crops - Vanilla

Growing Vanilla In A Polytunnel

Vanilla is a fragrant spice obtained from the orchids belonging to the genus Vanilla. Though challenging to grow in a temperate climate, you might potentially be able to grow this tropical plant in a heated undercover growing space like a hothouse, greenhouse or even perhaps a polytunnel

Key Information

There are three primary species of vanilla cultivated worldwide, all originating from a species initially discovered in Mesoamerica, notably in regions that now constitute parts of modern-day Mexico. 

These species include V. planifolia (also known as V. fragrans), cultivated primarily in Madagascar, Réunion, and various tropical regions bordering the Indian Ocean; V. × tahitensis, grown in the South Pacific region; and V. pompona, which is native to the West Indies, Central America, and South America. 

Among these, V. planifolia, commonly referred to as Bourbon vanilla, constitutes the majority of the world's vanilla production.

Are Vanilla Beans Hard to Grow?

It has to be said, first of all, that growing vanilla is not a beginner's pursuit. However, if you are an accomplished and experienced gardener looking for a real challenge then you may like to give this tropical exotic a go.

Vanilla is a vining member of the orchid family and can be very fussy. Like some other orchids, it will need tender attention and the perfect environment before it will set a crop. If you manage to get some vanilla pods/beans, however, you will surely gain a lot of satisfaction that all your immense efforts and expense have paid off.

The Preferred Conditions for Vanilla

Growing vanilla basically requires the faithful recreation of the tropical environment where these vines naturally grow. ]

Vanilla vines are extremely sensitive to heat, light and moisture and all three will have to be perfect in order to have success with these plants. The temperature in the growing location must be kept consistently at 26-7 degrees Celsius for the plants to survive and thrive. Bright but diffuse light is ideal. 

The water and humidity requirements are complicated. In order to produce pods, the vanilla vines will require distinct wet and dry seasons. 

More detail on the ideal conditions can be found in the care tips section below. 

What You Will Need to Grow Vanilla

  • Vanilla orchid plants (Vanilla planifolia or other suitable species)

  • Support structure (such as a tree, pole, or trellis)

  • Warm, tropical to subtropical climate or suitable growing environment (greenhouse/ polytunnel/ controlled indoor environment)

  • Well-draining soil or substrate (orchid mix, bark, perlite)

  • Adequate sunlight (filtered or indirect sunlight for 6-8 hours daily)

  • Regular watering, maintaining soil moisture (avoiding waterlogging)

  • Balanced, water-soluble fertilizer formulated for orchids or epiphytic plants

  • Training materials (to encourage vine growth and flowering)

  • Mulch (to retain soil moisture and regulate temperature)

  • Patience and attention to detail for proper care and maintenance

How to Grow Vanilla 

Three to five year old plants are available to by from a number of sites online and should be potted into pots slightly bigger than the pots they have arrived in. 

Container Grown

It is typically best to grow vanilla in a container of sufficient size rather than trying to grow this plant in the ground in temperate climes. 

Make sure that as you pot up, you also add support structure/ stakes up which the vanilla vine can climb.  For container-grown plants, providing adequate support is essential, particularly for vines reaching a height of 3-5 feet. 

Opting for a clay pot with a diameter of 30-40cm or larger offers sufficient space for your orchid to thrive, ensuring both size and stability for the plant. 

A clay pot promotes a healthy root system. It's crucial to ensure excellent drainage by using a porous potting mix and incorporating a drainage hole at the bottom of the pot to prevent waterlogging and promote optimal growth.

Care Tips for Vanilla 

Since vanilla is fussy about its growing environment, this is a plant that will require quite a lot of care and attention, to make sure that it gets the conditions that it needs. 

When does Vanilla Flower

Vanilla plants will be at least three before they will produce any flowers. Even once they reach flowering age, they will not flower unless they experience the right conditions including a wet season and a dry season. 

The vine must be stressed by being deprived of water for 6-8 weeks in order for it to produce flowers. Oaf course, flowers must appear for a harvest to be derived from a vanilla vine. 


You will need to pollinate the flowers in order for beans to form. To pollinate, remove the lip of the flower. Take the pollen from the anther area of the flower and place it in the nectar-containing stigma, a flap on the top, right column behind the flower. 

Pollinated flowers will then produce the green beans. These beans must then be left on the vine for six months to allow the vanilin (which gives the vanilla flavour) to develop.

Growing habit

Vanilla grows in a vine-like manner, typically climbing up existing trees, poles, or other supports. If left unattended, it tends to reach for the highest points of its support structure, resulting in limited flower production. 

To optimize growth and flowering, growers annually train the higher parts of the plant downwards, ensuring that it remains within reach of standing individuals. This practice effectively stimulates flowering and facilitates maintenance.

Plant Light Requirements

Vanilla plants ideally require bright, indirect sunlight for approximately six to eight hours daily. However, in temperate regions where sunlight intensity may vary, providing filtered or diffused light is crucial to prevent leaf burn while ensuring adequate photosynthesis. 

Shading structures/ greenhouses or polytunnels moderate light exposure, mimicking the tropical conditions optimal for vanilla growth. 

Additionally, supplementing natural light with artificial lighting, particularly during periods of reduced sunlight in winter, can help maintain consistent growth and flowering cycles helping to bring about a vanilla harvest. 

Temperature Requirements

Vanilla plants flourish within a defined temperature range, predominantly thriving in tropical to subtropical environments. 

They typically thrive in daytime temperatures ranging from 21°C to 29°C, while nighttime temperatures slightly cooler, 15°C to 21°C, are preferred. 

These temperature ranges promote robust growth and flowering, which are of course essential for optimal vanilla bean production. 

Potting Mix

The growing medium should be a specialist orchid compost or another specially formulated potting mix suited to this and other related tropical plants. 

Watering a Vanilla Bean Plant

As mentioned above, vanilla bean watering requirements alter throughout the year, as the plants require us to mimic the weather patterns of their natural environments, where there are both wet and dry seasons. 

During the growing season, typically spring and summer, vanilla plants benefit from regular watering to maintain soil moisture levels. However, it's essential to avoid overwatering, which can lead to root rot and other water-related issues. Instead, aim to keep the soil consistently moist but not waterlogged.

During the dormant period in autumn and winter, reduce watering frequency as the plant's growth slows down. Allow the soil to partially dry out between waterings to prevent waterlogging during colder months when the plant's water requirements decrease.

Remember, the plant must be deprived of water for 6-8 weeks in order for it to produce flowers.

When to Fertilise a Vanilla Plant

Start fertilizing your vanilla plant in early spring as it awakens from dormancy and begins displaying signs of fresh growth. 

Opt for a well-balanced, water-soluble fertilizer specifically designed for orchids or similar epiphytic plants. 

Dilute the fertilizer as per the guidelines provided by the manufacturer, then gently apply it to the soil or substrate surrounding the plant's base. This ensures that the plant receives essential nutrients to support its growth and development as it enters the active growing season.

Reduce feeding as growth slows in autumn and then stop for the dormant season before resuming once more in the spring. 

Harvesting Vanilla Bean Plants

It is time to pick the beans when the ends begin to turn yellow. However, the work does not end there. 

Beans should be wrapped in a blanket for 48 hours and will develop a light brown colour. After this, beans should be dried in the sun for a month or more. When the beans turn dark and leathery then they are ready to use.

Disease and Insects

Slugs and snails may pose a threat to vanilla plants while they are young, and the plants may also occasionally experience insect infestations with pests such as spider mites, mealybugs, aphids, scale insects or thrips. 

On the whole, however, the largest threat to vanilla plants is likely to be root rot – in which fungal disease as well as waterlogging can be implicated. And other fungal issues such as powdery mildew, anthracnose, botrytis or bacterial leaf spot may also occasionally be issues. 

Varieties of Vanilla

Here are several varieties of vanilla suitable for indoor cultivation in the UK:

  • Vanilla planifolia: Commonly known as Bourbon vanilla, this variety is extensively grown worldwide. With adequate warmth, humidity, and light, it can thrive indoors.

  • Vanilla pompona: Also known as West Indian vanilla, this species hails from the Caribbean and South America. It shares similar requirements with Vanilla planifolia but may offer slightly different flavour profiles.

  • Vanilla tahitensis: Tahitian vanilla is renowned for its distinct floral and fruity flavour. Although it prefers warmer climates, it can be successfully grown indoors in the UK with proper attention.

  • Vanilla odorata: Indigenous to Central and South America, this variety is less prevalent but can still be cultivated indoors in the UK. Its flavour characteristics may vary from those of Vanilla planifolia.

(Alternatively, you could choose to explore UK alternatives to vanilla, such as sweet woodruff, meadowsweet, or sweet clover – these common plants, when dried, can be infused into custards and other desserts as with vanilla as long as these coumarin containing plants are used in moderation – take care and always take advice if not an experienced forager).

Top Tips for Growing Vanilla in a Polytunnel 

Cultivating vanilla in a polytunnel within the UK offers a controlled setting reminiscent of its tropical habitat. Here are key guidelines for effective cultivation:

  • Provide Structural Support: Vanilla, being a climbing plant, requires robust support like trellises or poles to facilitate vertical growth.

  • Maintain Optimal Temperature: While polytunnels create a warmer environment, supplement with heating, especially in colder periods. 

  • Optimize Humidity Levels: Vanilla thrives in high humidity so keep this high inside your polytunnel. 

  • Ensure Adequate Ventilation: To prevent fungal issues, install vents or fans within the polytunnel to promote airflow.

  • Provide Indirect Sunlight: While light is crucial, shield vanilla from direct sun to prevent leaf scorching. Position the polytunnel to receive filtered or indirect sunlight, or use shade cloth.

  • Use Well-Draining Soil: Employ a potting mix rich in organic matter for optimal drainage, preventing root rot.

  • Water Carefully: Keep soil consistently moist, avoiding waterlogging. Water when the top inch of soil is dry, ensuring proper drainage.

  • Regular Fertilization: Apply balanced, water-soluble fertilizer formulated for orchids or epiphytic plants every two to four weeks during the growing season.

  • Encourage Flowering: Stimulate flowering through regular pruning and training. Train vines downward and maintain manageable lengths through pruning.

  • Monitor for Pests and Diseases: Regularly inspect for pests like spider mites and mealybugs, as well as fungal diseases such as powdery mildew. Promptly treat any infestations to safeguard plant health.

By adhering to these recommendations and creating suitable conditions,you can successfully obtain a yield of vanilla from your own polytunnel here in the UK. 


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Delicious Magazine. (n.d.) 37 Vanilla Recipes. [online] Available at: 

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