Vegetables
As the days get longer and soil temperatures rise, established plants and 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.
Sow runner beans in a sunny spot.
Smaller cucumber varieties (Lemon, True Lemon) 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. Cylindra is a good keeper and its shape makes it useful for bottling, while Derwent Globe is a proven round variety. Sow beetroot seed about 1cm deep. A beetroot seed is actually a cluster of three or four seeds, so when the seedlings appear, thin to 15cm apart.
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 and fatter stems. When taking spears, snap them off as close to the base as possible, taking care not to damage new buds. Apply general fertiliser at the rate of 100g per sqm, before harvesting starts, then liquid manure regularly for the rest of the growing season. Established asparagus beds can produce for 15 to 20 years, making the initial outlay well worthwhile.
Sweetcorn can still be sown. Choose a faster-maturing variety, such as Florida Supersweet, 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. Corn also needs potash. Apply 45g a sqm before planting.
Celery plants can be transferred to the garden now. Space them 30cm apart in trenches dug 30cm deep and filled with well-manured soil.
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 and swedes can be sown in cooler parts of the South Island.
Flowers
This is also a busy month in the flower garden.
Half-hardy plants such as marigolds, zinnias, salpiglossis and bedding dahlias tolerate some chill but are likely to be killed by late frosts.
For better flowers, add well-rotted compost and a light dressing of bone dust to the ground worked into the top 20cm where they are to grow.
Love-in-a-mist (nigella,) candytuft, larkspur, calliopsis, sweet sultan, clarkia and Shirley poppies should be sown where they are to flower.
Phlox is a sweet-scented perennial that comes in shades of pink, lavender and 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. Do not remove foliage until it has turned yellow.
Dahlias may still be planted and old clumps of tubers lifted and broken up for replanting. Stake when planting.
Blue flowers give a cool effect in the garden on hot summer days. As well as perennial delphiniums and Campanula persicifolia, try annuals such as larkspur, cornflower, nigella, California bluebell (Phacelia campanularia), nemophila and kingfisher daisies (Felicia).
Greenfly are a common problem on roses and, under the right conditions, can spread rapidly. They can be sprayed with soap solution, which will not harm bees, or a commercial product.
Fruit
Hardier tomatoes can be planted outdoors this month, but the plants will need shelter from strong westerly and southerly winds. Set stakes before planting so the roots will not be damaged. Tomatoes need rich, well-drained soil (add a sprinkling of potash) and if the ground is very acid (pH less than 5.5) a handful of lime to every square metre. Liquid manure once the first fruits set helps ensure a good crop.
