Climate change crops to buffer the heatwaves
Our maritime climate has always brought a cocktail of unpredictable weather – but even this meteorological framework is transforming. Global warming is likely to exacerbate the UK’s mild winters and high rainfall, so we’ll see more extremes of drought, heavy rain and hard frosts.
These alterations in global temperatures and disruption of regional weather patterns pose a major threat to food security. The UN’s Food and Agriculture Organisation estimates globally 75% of crop diversity was lost between 1900 and 20001. Now, nine plant species account for two-thirds of total crop production globally.
Climate change may have other effects on our delicate veg plot ecosystems too. Flowers will bloom earlier or later, so there’s a mismatch between pollinators and plants. And UK plant pests will become more diverse (many newcomers have been discovered, including the allium leaf miner). Diseases may become more prevalent and be harder to manage.
While nurturing your soil is the building block for mitigating poor plant health, drought and flooding – diversity can be the cement that holds it all together.
Choosing a wider variety of vegetable varieties could be the key to shoring up climate and food resilience. Growing different types of vegetable within one vegetable family, or experimenting with different varieties, helps to spread the risk in case of crop failures. It also offers rich, heterogeneous material for insects, birds and mammals, which in turn help to mop up ‘pest’ insects.
More adaptable, hardy varieties of vegetable - that can better tolerate wet ground, or drought - will become even more important as the climate changes. When planning your plot it might be useful, for example, to look at varieties that are grown further south, or in hotter areas of the world, as they will better represent what can be grown in the years to come.
And rather than sowing the same things at the same time every year, think about planting out crops early so they flower and fruit before dry weather, or stagger others - and plant into containers - so there’s less chance they will be sit in waterlogged soil in a wet winter and spring.
Many sturdy heritage varieties – like those conserved by our Heritage Seed Library - can withstand drought or waterlogging, or bolt less quickly. Lettuce ‘Bronze Arrow’ is drought and cold hardy, so ideal for autumn sowing and overwintering. And kale ‘Ragged Jack’ is very hardy, producing leaves even in the depths of winter - helping to extend the season.
Perennial vegetables, which don’t rely on one season’s weather for success, can become acclimatized to your particular soil. Many of these plants also have longer roots, so they can withstand climatic changes more easily, capturing carbon while they do so, and needing less watering.
Try these climate-change crops 🔗
Skirret (Siam sisarum)
Hardy, herbaceous perennial grown for its slender, peppery roots that taste like a cross between a parsnip and a carrot. It can tolerate a range of temperatures and has few pests.
Grow: Grown from seed in March/April, or from one-year-old crowns. Plants can grow to around 4ft tall with lacy umbels. Once this foliage dies back in autumn, check for roots. Harvest a portion and replace for next year’s crop. For a decent yield, and superior flavour, wait to harvest in the second year. Shoots can also be forced and eaten like spring greens – but this is best done when plants are established.
Top tips: Skirret likes moist soil with plenty of organic matter. Water well to get established and to stop the roots from becoming woody.
Eat: Can be used like any root veg - roasted or sauteed with butter, or cubed and parboiled for soup.
Scorzonera (Pseudopodospermum hispanicum)
Also known as black salsify, this member of the lettuce family is a perennial root crop, with long taproots that help it cope with drought. It can tolerate temperatures as low as -20C, has few pests and has a good resistance to bolting. Can also be grown in containers.
Grow: Regularly sow seed 1cm deep outdoors from April, placing three seeds every 15cm. Sow in rows 20-30cm apart. Thin to leave the strongest plant. If you want longer roots, sow in deep soil. They can take a little while to germinate so be patient.
Top tips: They need plenty of sun to produce decent roots. Weed around the roots but avoid damaging them as this can lead to ‘forking’.
Eat: Roots can be left in the ground and harvested as-and-when you need them. Like parsnips they’re said to get better with frost. The dark skin can exude a sap so part-cook and then peel. Lovely roasted or mashed. The young spring shoots, which look like blades of grass, are also edible.
Caucasian spinach (Hablitzia tamnoides)
Long-lived climbing perennial vine that offers tasty baby leaves that taste of spinach. Provides year-round greens and tolerates shade. Once established, plants are very hardy, down to -20C.
Grow: It needs a period of cold to germinate so you can sow in autumn and leave in pots over winter, or stratify seeds in spring the fridge for 7-10 days before sowing.
Top tips: The plants like rich, loamy soil and take three years to properly establish, so water well in dry periods in the first few years. Young plants may need protection from slugs.
Eat: Harvest February to June, adding young leaves to salad. Older ones can be used like spinach and stirred into stews, or blitzed into pesto and pasta sauces. Vine tips and flower buds can also be eaten.
Endive (Cichorium endivia)
A hardy substitute for lettuce, which can cope with high temperatures, and is low maintenance with few pests. They come in all sorts of colours, sizes and shapes.
Grow: Sow indoors or out, in late spring, in a sunny location. Sow little and often for a regular supply until the end of August.
Top tips: Blanch under a bucket or large pot for two weeks once the leaves are formed to reduce the bitterness of the leaves.
Eat: Harvest as a cut-and-come again salad leaf from spring to autumn – the bitter leaves lend themselves to winter salads with fruit or cheese. Some can produce mature heads, which will be ready three months after sowing, and can be baked or braised whole.