I find it wise to become reacquainted with the hoe at this time of year - regular hoeing on dry days will reduce weed growth and save a lot of hand-weeding down the line. Sowing your seeds in well marked rows will give you good indication of newly emerging seedlings and help to prevent any accidents.
Be aware of the dreaded late frost; it is still a risk at this time of year, so protect tender plants with fleece or a cold frame, hardening them off during warmer nights. Haulms of early potatoes will require earthing up. Once they have reached ten inches high, draw up the soil over the leaves until completely covered, forming a flat topped ridge - it should, once finished, resemble a newly ploughed field, protecting the leaves from any late frosts and allowing a greater depth of soil for tuber growth.
Asparagus fever has struck! We check our asparagus beds every morning for new growth – it may seem like an obsession, but the spears can put on six inches of growth overnight and are best if eaten straight away. If they have been left too long, the spears can become woody. Keep an eye out for asparagus beetle and pick off, if present.
Our summer brassicas are ready to plant out. Planting in fertile, free draining soil will give you the best chance of success. Planting deep and firming in will encourage sturdy root growth preventing the brassicas from rocking in the wind.
Our polytunnels are undergoing a transition period. Clearing the last of the overwintering crops makes way for tomatoes, chillies, aubergines and peppers. It is now warm enough to move them from the safety of the propagation tunnel and into their final home. Whenever planting in a covered growing area, water will be the main issue. Too much? Not enough? These are always the questions we ask. Incorporating lots of well-rotted organic matter will help with water retention and of course plant health. I find watering little and often to be ineffective, as most of the water will evaporate with the early summer heat. I water once a week in spring and twice a week in summer soaking very well, making sure the water penetrates the soil fully. Frequently damping-down paths and the walls of your poly- or glasshouse will increase the humidity and lessen the transpiration rate of your plants, and in turn the need for water is lessened.
As your broad beans start flowering, blackfly becomes a real threat – an infestation can destroy a crop in a matter of days. To prevent, pinch out the top three inches of growth, removing the breeding habitat and promoting branching of the plant, in turn increasing yield. A strong jet of water, or simply removing blackfly by hand, can also be effective. Companion planting with edible flowers like nasturtiums and calendula will lure the aphid away from your precious crop.
As crops begin to fill out, weeding will be reduced, however keep the onions and root crops well weeded – having thinner leaves means they struggle to compete with fast-growing weeds. Many of the common garden weeds are not always destined for the compost; some, like chickweed and hairy bittercress, find their way into summer salads.
The winter garlic will have produced flower spikes or scapes. These need to be removed to prevent the garlic from becoming woody before harvesting. Luckily the scapes are a delicacy to the chefs at River Cottage, and can be steamed or seared on the griddle and eaten like asparagus. The leeks are ready to be planted out. My preferred method to provide the blanching they need, is to dig a hole six inches deep, drop your seedling in, backfilling with water only. This will be sufficient to settle the leek in without any further firming in. I tend to harvest the leeks slightly smaller than most, so I space closer than convention at about 15 cm apart, which is ample room for growth right through to early winter.
Edible flowers have always been at the forefront of our summer menus, usually as a bi-product of companion planting. We grow nasturtiums, calendula and viola for trap (sacrificial) plants. All offering beautiful and delicious edible flowers, whilst keeping the aphid, caterpillars and slugs away from our precious crops. Borage is one of my favourite edible flowers, and with the delicate flavour of cucumber, it’s a delicious addition to ice water, cocktails, salads or even dessert plates. Grown as an insect attractant it hums with bees at this time of year, proving its worth for increasing pollination.
Once you are confident that the frosts are well and truly gone, it is safe to plant Mediterranean crops outside. Be sure to grow them in the sunniest position possible, preferably up against a wall for shelter from strong winds. I tend to grow tomatoes in the polytunnel, wanting for a higher yield, but there are fantastic outdoor varieties available if inside space is not an option. Keep side shoots on the tomatoes pinched out to focus the plants’ energy on truss and fruit growth. This will also decongest the plant, allowing airflow and helping to keep your plants free from fungal disease.
Strawberries will start producing runners in June and can be used to propagate new plants for future use. I cut off runners at this time of year anyway, which concentrates growth to the parent plant for fruit production. Pick regularly, removing any rotting or diseased fruit and net, if birds are an issue. We grow three varieties: an early, mid and late summer strawberry; staggering the harvest throughout the season to give the preserving pan a break!