One of the great pleasures of summer is opening the greenhouse door early in the morning and being greeted by the scent of tomato leaves, warm compost and ripening fruit. By July and August, a greenhouse becomes a world of its own, producing crops that simply wouldn’t perform as well outdoors in the British climate.
People often ask me what I would grow if I had only one greenhouse. The answer depends on taste, of course, but there are certain crops I return to year after year because they are productive, reliable and enormously rewarding. Whether you’re a seasoned gardener or just starting out, these are some of the best plants to grow under glass during the summer months.
1. Tomatoes
If I could only grow one crop in a greenhouse, it would probably be tomatoes. Nothing from a supermarket comes close to the flavour of a tomato picked warm from the vine. A handful of plants can produce an astonishing harvest through the summer and provide fruit for salads, sandwiches, sauces and countless summer meals.
Expert tip: Plant tomatoes deeply, as they produce roots all along their buried stems. Support them well, remove lower leaves as they grow and keep ventilation good to reduce the risk of disease.
2. Cucumbers
Cucumbers thrive in the warm, sheltered environment of a greenhouse. They are among the most productive crops you can grow and seem to reward every harvest with even more fruit. Freshly picked cucumbers have a crispness and flavour that rarely survives the journey from commercial grower to supermarket shelf.
Expert tip: Train plants vertically to maximise space and improve airflow. Water regularly and begin feeding once flowering starts.
3. Peppers and Chillies
Many peppers and chillies struggle to ripen reliably outdoors in Britain, but they flourish under glass. The extra warmth encourages strong growth and allows fruits to develop their full colour, sweetness and heat. From sweet bell peppers to fiery chillies, these plants are both productive and ornamental.
Expert tip: Use a rich, free-draining compost and feed regularly once flowers appear. Avoid overwatering, as peppers generally prefer slightly drier conditions than tomatoes.
4. Aubergines
Aubergines are among the most beautiful crops you can grow in a greenhouse. Their glossy fruits and attractive foliage make them as decorative as they are productive. While they require warmth and consistent care, the results are well worth the effort.
Expert tip: Keep plants evenly watered and feed generously throughout the growing season. Consistent moisture is essential for good fruit development.
5. Melons
Melons are not the easiest crop to grow, but they are undoubtedly one of the most rewarding. The first time you walk into a greenhouse and catch the perfume of a ripe melon hanging from the vine, you’ll understand why gardeners become so enthusiastic about growing them. The stable warmth of a greenhouse gives them the best possible chance of success.
Expert tip: Maintain consistent moisture, feed regularly and ensure good ventilation. Use netting or old tights to support developing fruits.
6. Salad crops
Lettuces, rocket and mixed salad leaves are ideal for succession sowing throughout the season. Greenhouse-grown salads are often fresher, more tender and more flavoursome than anything you can buy. By sowing little and often, you can enjoy a continuous harvest for months.
Expert tip: During periods of intense heat, provide some shading to prevent plants from bolting too quickly.
7. French beans
French beans are often overlooked as greenhouse crops, but they perform exceptionally well under protection. They flower earlier, crop heavily and produce tender, sweet beans throughout the summer.
Expert tip: Sow in stages every few weeks to extend the harvest season and ensure a steady supply of fresh beans.
8. Courgettes
Courgettes are famously generous plants. A single healthy specimen can provide more fruit than many families know what to do with. The protection of a greenhouse helps maintain strong growth and allows plants to produce heavily throughout the season.
Growing tip: Harvest fruits when they are still young, around 15–20cm long, for the best flavour and texture.
9. Strawberries
Growing strawberries under cover produces cleaner fruit, extends the cropping season and reduces problems caused by rain and soil splash. Picking a bowl of warm strawberries straight from the greenhouse remains one of summer’s simplest pleasures.
Expert tip: Grow in pots, troughs or hanging baskets to keep fruit clean and make harvesting easier. Remove runners unless you’re propagating new plants.
10. Herbs
A greenhouse is the perfect place to keep a ready supply of fresh herbs close at hand. Basil, parsley, coriander and dill all benefit from the warmth and protection, allowing you to harvest fresh leaves throughout the summer.
Expert tip: Group herbs according to their watering needs and growing preferences to make management easier.
11. Crops for the ambitious greenhouse gardener
One of the real joys of owning a greenhouse is the opportunity to experiment. Figs, peaches, nectarines and grapes can all thrive under glass and often produce fruit of exceptional quality. These crops require patience, but they can transform a greenhouse from a productive growing space into something truly special.
Expert tip: Good ventilation and careful pruning are essential when growing greenhouse fruit trees and vines.
A healthy and productive harvest
A greenhouse changes the rhythm of gardening. It allows you to sow earlier, harvest longer and experiment with crops that might otherwise be impossible in our climate. Whether you’re growing tomatoes for the family kitchen or trying your hand at peaches and melons, the rewards extend far beyond the harvest itself.
Summer is when a greenhouse truly earns its keep. It becomes a place of abundance, experimentation and daily discovery, providing not only fresh produce but some of the most satisfying moments in the gardening year.
Diarmuid Gavin is brand ambassador for Hampton Greenhouses.