Your greenhouse can become a powerhouse for winter crops – and that’s with the lights out and the heating off.
The lights flickered, hesitated, flickered some more, and then finally went out here over Christmas. Our ‘big’ power cut lasted the best part of a single daytime’s feebly lit hours. Compared to others, we got off lightly, and the woodburner became the source of the deep elemental aura that only a storm-induced power loss can bring. It was while enjoying this nature-induced outage that I (not for the first time) thanked my lucky stars that I don’t heat my lean-to greenhouse, other than with renewable and free sunshine. Although my electricity is from a 100% ‘green’ source, I can think of more efficient, as well as more financially, environmentally and morally sound ways, of using any hard-won energy. That means my greenhouse is cold and subject to winter’s temperature swings, but it doesn’t mean it’s not quietly prolific.
With dusk, it dawned that a hot meal that evening was unlikely, and thoughts turned to assembling a cold midwinter platter by candlelight. With sprouts and parsnips stood down, the search was on for some cook-free greens, and first stop was my greenhouse. With memory cells dulled a little since autumn’s sowing-fest, it was with sheer delight that – head-torch donned – I set about harvesting some reliable old friends, as well as some new faces.
Not plain old mizuna, but chunky-leaved mizuna ‘Waido’**, dark-leaved F1 ‘Red Knight’**, and frilly ‘red mizuna’*; not just green rosettes of tatsoi, but F1 ‘Red’**, and F1 ‘Kuro’* (a hybrid between tatsoi and pak choi); not only red pak choi, but yellow ‘Santo Round Leaved’*, and dark ‘Green Boy’*, too. There are also some first-timers to my winter salad bowl: Chinese salad cabbage ‘Bekana’*, with long, juicy midribs to its leaves; ‘Yukina’*, a giant tatsoi making rosettes of crinkly leaves, and the wonderfully-named ‘Mispoona’*, a hybrid between mizuna and tatsoi making (the packet says) a big rosette of chunky, flavoursome leaves (they’re well on the way). That old wintertime stalwart ‘Red Mustard’ has a new pretender vying for the top ‘hot and peppery’ spot: mustard green ‘Dragon’s Tongue’* is mild enough to eat raw when young, then gets hotter as it matures, when it’s good in stir fries and curries. With names like these, it’s little wonder the order forms were overflowing.
None of my winter greens have called for a jot of extra heat to grow. They were all sown between late August and the middle of September last year, in multi-cell trays of peat-free compost. They germinated on the greenhouse staging, were grown on, and then planted, in mid-November, into the big pots (recycled sheep lick tubs) I grew last year’s tomatoes in. Determined to get another harvest from the compost in them (my own 50:50 mix of sieved leaf mould and worm-worked compost) I replaced the top tomato-tired 5cm with some fresh, rejuvenating mix. Just over two months on, I’m doing a regular pick of salad leaves several times a week, and they taste a mighty lot better than any ‘bagged salad’ I’ll ever buy. I’ve watered, sparingly, on an only-if-needed basis, and ventilated with impunity – the biggest threat to these cold-season stalwarts isn’t low temperatures or lack of light, but stale, damp air which encourages grey mould (botrytis).
My ‘power cut salad’ was just a taster of things to come. Having made it through dark December’s doldrums, each lengthening day now brings a mite more accelerating growth. In a month or so’s time, when the plants are around the size of my outstretched hand, tasty, crunching salads be will a daily treat, while whole plants can be cut for cooking, leaving more room for their neighbours. I can’t wait to slice up a fully grown ‘Mispoona’ or a ‘Dragon’s Tongue’ and send them sizzling into hot oil. Later still, most will be running to flower, although their leaves and succulent stems will still be edible, either raw or cooked; by then I’ll be struggling to find the heart to pull them up to make way for successor crops. All of this comes courtesy of a greenhouse warmed only by the strengthening sun. A decent-sized coldframe, an unheated porch or even the windowsill of an unheated room will grow these greens, too.
To crown it all, the yellow and white pollen- and nectar-rich flowers of most winter greens (from the cabbage family) are irresistible to the first adult hoverflies lured out on warm spring days. Their larvae feed greedily on equally early outbreaks of aphids, so to entice hoverflies into your greenhouse, let a few plants flower their heads off near its open doors.
So far, here in North Wales it’s been ‘winter’ in name only. Bar a few odd nights of sharp frost, a soggy mildness has lain over my garden, enlivened only by the run of storms which sent me out to cut my first blackout salad. I’ve been lucky; there’s been no long run of sub-zero nights, which can freeze every pot of compost in my greenhouse solid – but there’s time yet. Should we get some nights brittle with frost, that will ice-etch the greenhouse glazing, and my greens will go on a temporary grow-slow. They’ll sag and sulk, looking for all the world as if they’re goners, but as the freeze retreats they’ll pick up where they left off, dashing on toward spring. Neither they nor I will be bothered one bit if the lights go out, and I don’t need to fret about propagators going off, or gas or paraffin running low.
Energy – where it’ll come from, how much it might cost, how we can better value and conserve it, and what effect using it has on the world around us – is rarely out of the news. We use energy in our gardens too, in all sorts of different ways, some less obvious than others. Winter greens are the ultimate in low-energy vegetables. Growing easily and dependably through the darkest days of the year, they bring colour, freshness and flavour to our lives, for months on end, when we sorely need it.
The lights are flickering again. It must be time to go and munch on some ‘Mispoona’…
* Available from Real Seeds
** Available from www.seedaholic.com
Text and images © John Walker