Vegetables
As the days get longer and soil temperatures rise, established plants and young seedlings grow faster, while seed sown now is almost certain to germinate.
French and butter beans can be sown in the open. Place the seeds singly, about 15cm apart and 5cm deep.
Runner beans for growing up trellises or on frames can also be sown now in a sunny spot. .
Smaller cucumber varieties can be sown in rich soil but, in cooler areas, these and other cucurbits, including zucchini (courgettes), are better grown from plants bought from a garden centre.
Main-crop beetroot can be sown, to mature in autumn and stand over winter. Sow beetroot seed about 1cm deep. A beetroot seed is actually a cluster of three or four seeds, so when the seedlings appear, thin them to 15cm apart. The thinnings can be used to fill gaps in rows.
Asparagus can be harvested now and spears can be taken over the next month. If this is the first season for your asparagus, resist taking any shoots so the root system can develop. This self-discipline will pay dividends in years to come with more, fatter stems to pick. When taking spears, snap them off as close to the base as possible, taking care not to damage new buds around them. Give an application of general fertiliser, at the rate of 100g per sq m, before harvesting starts, then liquid manure regularly for the rest of the growing season.
Sweet corn can still be sown. Choose a fast-maturing variety and sow in groups of six to eight plants, 15cm apart in each direction, to help fertilisation. The plants need shelter from cold winds and plenty of compost and lime.
Peas, lettuce, carrots, spring onions, radish and turnips can still be sown for succession crops.
Winter greens, savoy cabbage, broccoli, Brussels sprouts, kale and cauliflower should be sown now.
Flowers
Love-in-a-mist (Nigella) candytuft, larkspur, Calliopsis, sweet sultan, Clarkia and Shirley poppies are among annuals that resent being transplanted and should be sown where they are to flower.
Phlox is a sweet-scented perennial that comes in shades of pink and lavender, as well as white. Plants should now be a mass of shoots. A little blood and bone worked in around the plants will ensure a good display in late summer.
Tulips and narcissi should be left as long as possible before lifting, cleaning, then replanting or storing. Foliage must not be removed until it has turned yellow.
Dahlias may be planted and old clumps of tubers lifted and broken up for replanting. Stake when planting to avoid damaging the roots later.
Fruit
Hardier tomatoes can be planted outdoors this month, but the plants will need shelter from strong westerly and southerly winds. Set stakes in position before putting in the plants so the roots will not be damaged. Tomatoes need rich, well-drained soil to which has been added a sprinkling of potash.
