Greenhouse Gardening in December: Seize the Season with Rob Smith
As the festive season envelops us in its wintry embrace, the thrum of life in our gardens may seem to hush. But inside the glass walls of the greenhouse, a gardener’s December is a prelude to spring’s symphony. I'm Rob Smith, and I invite you to join me in exploring how the use of a greenhouse this December can give you a significant leap forward in the coming season.
Strawberry Fields Sooner
Let’s start with something sweet: strawberries. December is the perfect time to pot up those vigorous strawberry runners into containers or hanging baskets, tucking them into the cosy confines of an unheated greenhouse. Doing so can coax an earlier crop from these beloved berries, often by a good 3-4 weeks. Varieties like 'Frisan' and 'Toscana', with their charming pink blossoms, are not just a treat for the eyes. These day-neutral types generously offer fruits from May until the first frost, promising a long season of harvests. Imagine biting into a succulent, home-grown strawberry in the late spring sunshine, all because you gave them a head start in the quiet of December.
Next, let’s talk herbs. Woody staples like rosemary and sage, along with the ever-versatile mint, don't need to take a winter break. Bring them into the greenhouse, and they'll keep adding their aromatic magic to your dishes. The controlled environment protects them from the harshest cold, ensuring fresh sprigs for that roast or stew whenever you fancy. This simple act of sheltering extends the season of these culinary treasures, and its as easy as moving a few pots into the greenhouse!
For those of us who love the structure and vibrancy that perennials and taller flowering plants bring to our gardens, the greenhouse is a perfect nursery. Autumn-sown foxgloves and perennial poppies benefit greatly from being overwintered under glass, producing bigger, more robust plants, ready to take to be planted out into the garden in spring. This head start results in a display that's not only earlier but produces more flowers, with each plant having had the chance to grow strong in the sheltered nursery of your greenhouse.
Fragrant sweet peas are next on the December agenda. These beauties can be sown now in deep modules or root trainers, the latter being particularly adept at encouraging long, healthy roots for sweet peas. But here’s a tip — elevate your trays to thwart any curious mice that might fancy a seed snack. And remember, watering is a minimal task during this month. Plants aren’t thirsty when the days are short, and overwatering can do more harm than good. I find it best to sow 3-4 seeds per module, resulting in strong little clusters of plants which form a denser looking display once planted out in the garden in spring.
In keeping with tradition, many gardeners begin sowing giant show onions on Boxing Day. The process starts in a heated propagator, where seeds germinate in the cosy warmth. As the seedlings emerge and bend in a natural arc, resembling a 'shepherd's crook', they signal readiness for the next stage. This crook shape indicates a strong root system and a healthy shoot, which will straighten as the plant grows. At this point, they can be transplanted to small pots or module trays and moved to a cooler position and out of the heated propagator. As spring approaches, these potential prize-winners are then transferred to the greenhouse to continue their growth. This tradition of sowing on Boxing Day might produce the best onions but could also be an excuse for us gardeners to escape the bustle of a house full of guests and find some peace in the sanctuary of their greenhouse!
In the heart of winter, the greenhouse stands as a beacon of productivity and promise. While the world outside may be in a state of rest, within these glass walls, the potential for the coming season quietly starts to grow. Be it the early stirrings of strawberry plants, the steadfast growth of herbs, or the delicate curves of onion seedlings, the greenhouse is a place where the fruits of tomorrow are carefully nurtured today, where each seed sown is a step towards a more beautiful garden.
But beyond the tangible yields of fruit and vegetables, the greenhouse offers something equally valuable – a haven of calm during the festive season. In the hustle and bustle of holiday celebrations, it provides a peaceful retreat, a space to breathe and enjoy a moment of solitude with nature. The greenhouse is not just a tool for growing; it's a sanctuary for the gardener's soul. Merry Christmas!
Images courtesy of Robert Smith and Darren Lakin
Om Robert Smith
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.Get to know Robert Smith
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