Written by Robert Smith 16 Nov 2023 13:51

Greenhouse Gardening

A Winter Oasis for Thriving Vegetables and unlocking the Secrets of Year-Round Harvests

As the winter chill creeps in and outdoor gardening takes a back seat, the greenhouse emerges as a horticultural haven for those eager to cultivate fresh vegetables even in the coldest months. In this article, we delve into the art of greenhouse gardening during winter, exploring how to nurture vegetables like garlic, onions, peas, mustard leaves and broad beans with care and success. There’s no need for any additional heat or grow lights, as these vegetables can cope with the cooler temperatures, happily growing in an unheated greenhouse.


Starting with Garlic and Onions

When winter unleashes its freezing grasp or brings unwelcome floods like we are seeing at the minute, the greenhouse becomes a saviour for starting garlic and onion sets. Plant these hardy vegetables in trays or pots filled with well-draining peat-free compost and place them in the protection of the greenhouse, ensuring they receive adequate sunlight. This controlled environment not only protects your crops from the harsh winter elements but also provides the perfect conditions for early growth. You'll be rewarded with robust plants ready for outdoor planting when the weather improves.  You can even start the jumbo-sized Elephant garlic in large pots, then when the outside ground becomes workable, you simply transplant them to where you want them to grow.


Easy Peasy

Peas, such as the delectable 'Douce Provence’ and ‘Meteor’, can be a delight to grow in a greenhouse over winter. You can sow them in large pots or troughs, allowing them to happily grow undercover without the fear of weather damage, or being eaten by hungry pigeons.  Sow these petite wonders in pots or trays, providing them with the shelter and warmth they need to germinate and thrive, then either leave them to grow under cover, or transplant them outside when they are around 5-10cm tall. By nurturing them indoors, you can enjoy a bountiful crop of peas before the traditional outdoor growing season begins, meaning you’ll have harvested your peas and still have time to plant your tomatoes next May. Imagine the satisfaction of harvesting sweet, juicy peas from your greenhouse before anyone else has even sown theirs.


Broad Beans: The Early Start

For those eager to get a head start on their broad bean crop, greenhouse gardening is the answer. Sow broad bean seeds in pots or trays in your greenhouse, then place them on an upside-down bucket to protect the newly sown seeds from hungry mice; this little trick works a treat and prevents you from having to re-sow seeds that were eaten.  Starting your seeds off in the greenhouse will result in plants which are ready to transplant into the garden several weeks ahead of their outdoor-sown counterparts. This means you can avoid sowing directly into waterlogged soil, giving your broad beans the best possible start.  Just remember to transplant your seedlings when they are around 10cm tall, as you want nice, stocky seedlings that will survive the winter.


The Mouse-Proof Solution

Peas and beans sown in a greenhouse offer another advantage: protection from nibbling mice. Mice find newly planted pea and bean seeds irresistible, often frustrating outdoor sowing efforts. By starting your peas and beans in the controlled environment of a greenhouse, you can deter these pesky critters and ensure your seeds sprout undisturbed.  Not only will this save you hassle, but it will also save you money!


Mustard Leaves: A Greenhouse Winter Marvel

In the realm of greenhouse gardening, mustard leaves emerge as an unsung hero, especially during the winter months. These resilient greens thrive in cooler temperatures, making them an ideal addition to your winter greenhouse, plus they can be sown right the way through to Christmas. Sow mustard seeds in trays or pots within the greenhouse and watch them flourish even when the mercury dips. Their vibrant leaves not only add a touch of greenery to the winter scene but also serve as a versatile culinary delight. Harvest your mustard leaves from the size of your middle finger, taking a couple from each plant and leaving the rest to grow.  Mustard leaves are great to add a zesty, peppery kick to salads, sandwiches, and stir-fries (in a similar way to rocket leaves). Embrace the simplicity of growing mustard leaves in your greenhouse, as they prove that even in the chill of winter, your greenhouse can yield an array of fresh and flavourful produce.



With a well-maintained greenhouse, you can extend your gardening season into the winter months, cultivating a variety of vegetables that thrive in the controlled climate. From garlic and onions to peas and broad beans, the possibilities are endless. So, no matter if you are simply starting your veg off under cover, or growing them to maturity, don't let winter's chill deter you. Embrace greenhouse gardening and enjoy a continuous harvest, setting the stage for a productive and rewarding year in your garden.


About Rob

Rob is a seasoned gardener, specialising in growing edible plants. Not only does he write for multiple national Gardening Magazines, but he also appears now and again on TV and radio, sharing his passion for the “Grow Your Own” lifestyle on social media (@robsallotment).  Alongside his public persona, Rob also works with several of the counties best known gardening companies, including Suttons, Thompson & Morgan, Dobies, and The Organic Gardening Catalogue, to source new and exciting types of fruit, veg and flowers to be launched into garden centres across the UK and Europe.  At home you will find him in his Kitchen Garden, come rain or shine, accompanied by his faithful companions, Nipper and Reggie.

Rob's greenhouse is a Halls Cotswold Blockley.

Images courtesy of Robert Smith and Darren Lakin