Keen gardeners are beginning to leaf through seed catalogues to decide on crops for the coming year. With such a large choice of varieties, it’s always a balance between those you know and ones you’d like to try. If you’re very organised, you’ll have carried out 2016's new year’s resolution and noted sowing, planting out and harvesting dates, and how the varieties fared.

Sadly, the odds are that this wonderful resolution fell by the wayside and you have to rely on a fuzzy memory. Ideally, you’d be like a Victorian head gardener and have records spanning the last 50 years, but you can, at least, see how the late winter crops are doing and check which herbs will still be worth growing this year.

If some varieties have failed, try something else. But before writing off a variety, check that you sowed it at the right time and provided the correct growing conditions.

Vegetables sown too early mature quickly and are ready for harvest prematurely. I confess I sowed my Minicole cabbages in March, not April, to tie in with holiday arrangements and was punished with an August rather than September crop. Late sowings can be just as disastrous. Late winter cabbages need a long growing season, so they won’t heart up properly if sown late in May.

Unpredictable weather doesn't help. Every year is different and affects how quickly plants grow and how well they survive.

For what it’s worth, this winter seems fairly typical, with a cold November followed by milder December, capped by a small dose of snow and ice in mid January. The snow hasn’t arrived as I write, so I’ll nip into the garden and see how things stand just now.

Hardy brassicas and leeks take sub-zero temperatures in their stride. I’ve just finished a fine crop of Pandora leeks, and am delighted to see my next batch, Tandora, have shaped up beautifully with the late season St Victor set to follow. Well fed, watered and widely spaced leeks love it cold. Successional sowings of sprouts have been just as good, with Cascade seamlessly following Nautic. And the staying power of flower sprouts, a new kail/sprout cross, has been excellent.

Many other brassicas, especially late winter cabbages, love the cold but hate temperature fluctuations or mild conditions. This can lead to rot forming on the outer leaves. So, while it’s always best to clear away dead and rotting vegetation, it becomes essential during a mild spell.

On the other hand, severe cold puts paid to more tender celery and celeriac, and leafy endive flop fatally. I’ve even found that overwintering lettuces, such as Rougette du Midi, can decay in the polytunnel.

But other leaves do recover if temperatures rise. You’d expect kail to bounce back at the earliest opportunity and even the early winter Nero di Toscana is soon set to provide another picking. And although chard looked pretty miserable at the beginning of December, there are now just enough leaves for a fresh salad.

A tour round the herb garden is equally encouraging. Leaf celery is thriving, as are parcel, sorrel and salad burnet. Freshly picked herbs are even possible in the depths of winter.

Some unexpected plants can supplement the supply of fresh leaves. Even if you have to compost most of the leaves of neeps, some inner ones are still fresh and green and can be snipped over mashed neep. I much prefer growing white turnips, Armand or Purple Top Milan, for autumn and winter picking, not summer, and they too have a few leaves rich in nutritious antioxidants.

Without a large kitchen garden, supplies of fresh vegetables are very limited, enough for two people rather than a large family. But they’re an important source of nutrients you won’t get elsewhere.

For all the weather’s vagaries, my seed order probably won’t change much this year. Will yours?