December in the greenhouse

The article is written by Rob Smith

Whether it’s a proper greenhouse, a few cold frames or some old cloches patched together with tape and hope, these sheltered spaces come into their own now. They’re not just a place to hide from the weather, they’re a chance to get ahead while everything else is asleep.

Chillies and grape vines

One job I always start with is checking over my overwintered chillies. The ones in the heated lean-to might look like they’re just sitting there doing nothing, but dieback can creep in surprisingly fast if you’re not paying attention. I’ve had it before where a lovely old plant looks fine from a distance, but closer up the stems have gone brown and soft halfway down. When that happens, the best thing to do is cut back hard, snipping below any dodgy patches to healthy green wood. It stops it spreading and gives the plant a fair chance of bouncing back in early spring. The ‘Piquante’ pepper I’ve been growing is looking a bit sad this year, whereas last winter’s ‘Scallywag’ is still holding on well. Not every plant will make it through, but the ones that do tend to come back strong and early, so I always keep more than I think I’ll need.

Another task I like to get done now is pruning the grapevine. I’ve got one under cover that always tries to take over if I let it. The key with grapes is to prune when they’re properly dormant. I cut back the side shoots to just one or two buds from the main framework. If you leave it too late, you end up with weeping cuts as the sap rises early, and it just makes a mess of everything. A sharp clean cut is best, so decent secateurs really do make a difference.

Cleaning and oiling tools

There’s a nice quiet satisfaction to be found in a December greenhouse. It’s the perfect spot to do the sort of tasks that often get put off. Cleaning and oiling tools, for one. I set up a couple of boards across buckets as a makeshift bench and go through everything bit by bit. Trowels, secateurs, forks, all of it. I use a bit of wire wool to get off rust and sap, sharpen blades where needed, and wipe the metal over with Camellia oil. Wooden handles get a rub with linseed oil and a check for splits. It’s an old habit but a good one. Tools last longer and are much nicer to use when they’re looked after. It also gives me time to think about what I actually use and what’s just gathering dust.

Grow new crops

With the tomatoes long since cleared out, there’s usually a bit of bare space in the greenhouse this time of year, and I like to use it for sowing a few forcing carrots. ‘Carruba’ and ‘Amsterdam Forcing’ are my go-to varieties. They don’t mind the cold and they’re slow and steady over winter. I sow them in deep troughs filled with fine compost and cover them with fleece or an old bit of bubble wrap to hold the warmth in. A light sprinkle with the watering can now and then is all they need. It’s easy to forget about watering in winter, but a dry trough won’t get you anything. By the time the tomatoes are ready to go back in next year, the carrots will be out and onto the plate.

Christmas Day in our house wouldn’t feel right without a couple of homegrown lemons. There’s something very pleasing about nipping out to the lean-to and snipping a few fruits for drinks or a prawn cocktail. The scent alone is enough to lift your spirits. After picking, I give the plant a bit of winter citrus feed and make sure the compost hasn’t gone soggy. They like to dry out a touch between waterings, and decent drainage is a must. The lemons have earned their keep again this year, even if the harvest isn’t huge.

Boxing Day has always been the traditional time to sow exhibition onions, and I still follow that old routine. A tray of ‘Kelsae’ or ‘Galactus’ goes into compost on the windowsill or in a cool propagator. They don’t need heat, just time. Even if you’re not growing for size, it’s a nice excuse to start something fresh before the year is out. If big onions aren’t your thing, a tray of spring onions works just as well and they’re up in no time. The young shoots are lovely cut fresh and used like chives. It’s a quick job that gets you back out to the shed and gives you a bit of peace and quiet during the festive noise.

Overwintering plants

If you’ve got cloches or a cold frame, they’re useful now for sheltering anything that needs a bit of protection but doesn’t belong indoors. I’ve had good success keeping herbs like parsley and coriander going through winter, especially if I remember to lift them slightly or stand the pots on bricks to keep the roots out of the wet. I also like to use the cold frame for hardening off overwintered crops or for an early sowing of salad leaves once the new year turns. With the lid cracked open on mild days to keep the air moving, it’s amazing what’ll keep ticking over even in the darkest weeks.

These quiet days in December are often some of the most satisfying. The jobs aren’t showy and the rewards are months away, but there’s a sense of getting things in order. The greenhouse becomes a workshop, a potting shed, a place to plan and prepare. There’s still plenty of life in the garden, it’s just ticking away under cover for now. And when you do finally step back inside with the lemon tree watered, the onions sown, and the tools cleaned, you feel better for it.