Can potatoes be grown in a greenhouse?

The humble potato is a staple in gardens around the world, typically associated with expansive vegetable patches and dug up in the autumn. But as gardeners look to maximize space and exert more control over their crops, a common question arises: Can potatoes be grown in a greenhouse? The answer is a resounding yes. In fact, cultivating potatoes under glass isn't just possible; it can lead to healthier plants, larger yields, and the unique pleasure of serving your own homegrown new potatoes on Christmas Day.

This guide will walk you through everything you need to know about greenhouse potato cultivation, from the scientific benefits to the practical planting methods.

The Science Behind Greenhouse Spuds

Why bother using valuable greenhouse space for potatoes? Recent agricultural research highlights significant advantages. A 2025 study published in the Revista Brasileira de Engenharia Agrícola e Ambiental compared potato growth in greenhouse conditions versus open fields. The findings were definitive: potato plants grown directly in the soil inside a greenhouse produced the highest root, stem, leaf, and tuber weight -1.

The primary reason is the accumulation of growing degree days (GDD) . The study noted that plants in the greenhouse accumulated 2392°C GDD compared to just 1774°C in the open field -1. This controlled environment means plants can photosynthesize more efficiently, resulting in larger leaf areas (recorded at 4389 cm² in greenhouses vs. an average of 2078 cm² in other treatments) and higher stomatal conductance, which is essentially the plant's ability to breathe and grow -1. Essentially, a greenhouse offers a buffer against climatic variations, allowing for consistent, uninterrupted growth.

Method 1: Growing Potatoes in Containers

For most greenhouse owners, growing potatoes in containers is the most practical method. It prevents them from taking over permanent beds and allows for complete control over the growing medium.

Selecting Containers and Varieties

You don't need specialized pots. Containers must be at least 30cm (1ft) deep and wide, with adequate drainage -2. You can use traditional flower pots, specialized potato-growing bags, or even flexible plastic bags from a hydroponics store, which allow tubers to expand without distortion -7.
For variety selection, "first early" and "second early" varieties are the best candidates for container growing. Experts at the RHS recommend varieties like ‘Charlotte’, ‘Nicola’, and ‘Maris Peer’ -2. If you're aiming for a winter harvest, look for cold-stored tubers sent out in late July or early August, such as ‘Carlingford’ -5.

Step-by-Step Planting Guide

1. Prepare the Tubers: Inspect seed potatoes and cut away any rot. Large tubers can be cut in half, provided each piece has an "eye." Allow cut surfaces to dry or "harden" for 24 hours to prevent rotting -7.

2. Initial Planting: Add a 10-15cm layer of potting soil mixed with compost or well-rotted manure to the bottom of your container -2. Place one to three tubers on this surface (giving them about 30cm of space) and cover them with 15cm of compost -2-5.

3. Earthing Up (The Key to Yield): As the green shoots grow to about 15cm high, add more compost or soil, leaving just the top few centimeters of the plant exposed -5-7. Repeat this process until the container is full. This encourages the plant to produce tubers all the way up the buried stem.

4. Care and Feeding: Keep the soil consistently moist but not waterlogged. Potatoes are hungry plants; feed them with a high-phosphorus fertilizer (such as a 5-20-0 mix) to support tuber development -7.

Method 2: Direct Soil Planting in Greenhouse Beds

If you have dedicated greenhouse beds, you can plant potatoes directly into the soil. As the 2025 study confirmed, this method can produce the highest biomass yields -1.
To do this, plant the tubers in a trench about 30cm deep, spacing them 25cm apart -4. As the foliage grows, use a hoe to draw soil up around the stems (earthing up). This blocks light from reaching the developing tubers (preventing them from turning green and toxic) and suppresses weed growth -4.

The Christmas Potato: Timing is Everything

One of the greatest delights of a greenhouse is the ability to manipulate the season. By planting in late summer, you can harvest new potatoes for Christmas dinner.
To achieve this, you need to plant in late August or early September -2-5. Place the containers in a cool conservatory or greenhouse. As winter approaches, the critical task is to ensure the greenhouse remains frost-free. Potato foliage is extremely sensitive to frost and will die back if temperatures plummet -2. The foliage will naturally yellow in late autumn; at this point, you can cut it back and leave the tubers in the compost (kept fairly dry) until you need them -2.

Greenhouse vs. Open Field: A Quick Comparison

Advanced Techniques and Considerations

Aeroponics: For the tech-savvy gardener, research from the Czech Republic suggests that aeroponic systems (growing plants with their roots suspended in air and misted with nutrients) can dramatically increase the number of tubers produced per plant—up to 41 tubers per plant in some trials. However, these tubers are often smaller (mini-tubers) compared to the larger, heavier potatoes grown in traditional greenhouse substrates -6.

A Note on Sweet Potatoes: It's important to distinguish between regular potatoes (Solanum tuberosum) and sweet potatoes (Ipomoea batatas). Sweet potatoes are tropical plants that thrive in greenhouse conditions, requiring temperatures of 21–26°C (70–80°F) to crop successfully -3. Unlike regular potatoes grown from tubers, sweet potatoes are started from cuttings (slips) and need a long, hot growing season of up to five months -3-8.

Potential Problems and Solutions

While a greenhouse offers protection, it is not without its challenges.

• Pests: Greenhouses can sometimes harbor glasshouse red spider mite and whitefly -3. Regularly check the undersides of leaves and increase humidity to deter mites.

• Diseases: Potatoes grown in fresh container compost are less prone to scab and rots -2. Avoid planting in the same container soil year after year to prevent disease buildup.

• Temperature Spikes: In early autumn or late spring, greenhouses can overheat. Ensure you ventilate and shade plants when necessary, and consider using a fan to circulate air -5.

Conclusion

So, can potatoes be grown in a greenhouse? Absolutely. Whether you are a hobbyist looking to extend the season or a gardener aiming to maximize yield through controlled conditions, the greenhouse offers a versatile environment for potato cultivation. By choosing the right varieties, mastering the "earthing up" technique, and managing the internal climate, you can enjoy pristine, homegrown potatoes long after the outdoor harvest is just a memory. Happy gardening