Vegetable gardening is caught between two hard places. The summer’s drought has been ruinous for lettuces, spinach and leafy green crops. The cost of heating a greenhouse has soared, putting aubergines, peppers, cucumbers and indoor tomatoes beyond easy reach. In June, Kew Gardens opened a new area called Edible Science, aiming to “work towards more sustainable production processes”. I have just checked it out.
It stands on the site of Kew’s old walled kitchen garden, which once supplied food to King George III. Our eco-King Charles III will appreciate its ground rules. It is following a no-dig policy. Like the King’s garden at Highgrove, it avoids use of chemical weedkillers. It will soon include a shelter with an edible green roof of alpine strawberries, thyme and nasturtiums, whose peppery leaves are good in salads.
“Bee houses” will be placed around the garden and some of the cabbage plants will be left to run to seed so that Kew’s scientists can study their pollen. Some of the beds link up with existing research at Kew, whether on food plants in Mexico or the types of bean that will best resist drought.
This Edible Science area is another fine addition to the garden, one visitors will enjoy inspecting. It stands near the recently planted Agius Evolution Garden, which shows the advance of plants on our planet through the millions of years since life began. Like the Evolution Garden, it is the result of generous donations. Its budget was £280,000, to include a new pattern of paths with a hard surfacing of sustainable Cedec gravel.
Like me, the planners consider that vegetables are best grown in beds raised above the level of whatever passes for existing soil. Beds with porous edging have been built on top of it. As Kew has an abundance of homemade shredded compost, it was tractored round to the veg beds and laid to a depth of at least 1ft above the old soil’s level. The cost is way beyond normal gardeners’ budgets but the principle of raising beds and laying new soil is certainly not.
At Kew the capital budget has to cover the cost of gardeners to maintain the project. It has also paid for water points in the corner of each bed to which leaky hosepipes can be attached and run at ground level for an hour at a time. They are the most economical way of watering vegetables, especially in a garden which depends on one full-time gardener and volunteers.
With Helena Dove, head of the kitchen garden, I looked at progress since work began nine months ago. The visual impact of kitchen gardening is so quick. While my recently planted hellebores have been struggling to survive dry weather, Kew’s edible garden has acquired vertical lines and a green and jungly look. Curtains of gourds and edible climbers hang on metal arches.
I was impressed by wooden panels, each with five rows of slats, which are propped up at an angle above one of the beds like cold frames: they make supports about 3ft long for scrambling cucumbers planted beneath.
The Roman emperor Tiberius used to order his cucumbers to be grown on moveable frames, which could be sited wherever the sun was strongest early in the year. At Kew the cucumbers are raised under glass, like many of the vegetables in the Edible Science garden, and are then transplanted beside these frames in early summer. On their slats, cucumber Mini Munch and Bedfordshire Prize are growing happily: a good source of seeds for next year’s crop is dtbrownseeds.co.uk, which even lists one called Socrates.
How have the eco-rules worked out in practice? Dove explained to my group of fellow gardeners how she burns off existing weeds with a flame gun and never uses chemical weedkillers. She is still picking off the stems of bindweed by hand whenever they reappear.
I would never be so dogmatic. One targeted dab of glyphosate on the leaves and all that bindweed would have been harmlessly dead long ago: glyphosate kills by contact with leaves, not the soil. To stop weeds in the Cedec paths I bet that chemicals will have to be used anyway.
Dove and her team also never dig the ground: “The world,” she tells me, “has been doing fine without us.” I am a veteran of a type of digging called bastard trenching: it depends what you want to do with the world meanwhile.
Broadly I agree with a no-dig policy. Digging disturbs the soil and encourages weeds to germinate in it. In established veg beds, I too would prefer to top dress heavily with mulches after rain in winter and then hoe the surface lightly from time to time. However, deep mulches cannot be piled on year after year: there needs to be an interval in which forking is an alternative.
One of Dove’s excellent aims is to illustrate what owners of smaller gardens can grow. She has three good maxims: use vertical space; think in chunks of 1 sq ft at a time, marked out by canes laid on the ground; choose heavily cropping smaller varieties. I noted down the labels on her low-growing tomatoes, Tumbling Tom Red and Tumbling Tom Yellow, and her low peppers, Lemon Dream and Tangerine Dream.
I also learnt from her advice and example that the answer to growing proper spinach is to sow Malabar spinach under glass and set the young plants out in summer when they will make climbing plants with big green leaves, fully flavoured. Kings Seeds of Kelvedon, Essex supply packets for only £2.05.
Kew’s venture in Edible Science is keen to find edible vegetables that we are ignoring. I am not sure that the roots of ornamental cannas will ever dominate dinner tables. Yacon might perhaps have a future, but I will not give up on potatoes just because they have had a bad year of blight. Dahlia tubers may seem like another culinary dead end, but here I was updated by one of my fellow visitors.
Lucy Hutchings abandoned a career in fashion and jewellery in order to be self-sufficient in vegetables, feeding herself and her family. Gardening in bone-dry Suffolk, she has more than 160,000 followers on Instagram (@shegrowsveg) and tells me that she and her husband, a professional chef, grate some of the tubers of their dahlias when they lift them and then cook them as a tasty rösti.
What about that eco-flashpoint, wildlife? At Kew, labels like to spell out experience for visitors. After hearing about cohabiting with slugs, I hit on the label of the day: I illustrate it with this column. “We are currently experiencing lots of badger action . . .”: join the gang, Kew.
Chilli flakes and pepper will never deter a badger on the prowl. Stripy invaders are trotting through the garden’s gate at night and rootling in its dampened Ethiopian beds. Watering encourages them to play ball with Dove’s young vegetables in search of grubs and insects. I hate to mention it, Kew, but badgers have a history of being edible too.