Vegetables
Green manure crops, such as mustard or oats, can continue to be dug in and the ground prepared for seed-sowing by breaking down the surface with a fork and raking it level.
Dig green manure into the top 15cm of soil only, as the organisms that convert green manure to humus are more numerous there.
Do no digging if the soil is wet. This is especially important with heavy clay soils as they become concrete-like when they dry out after being dug when waterlogged.
Any swedes, carrots, parsnips and leeks still in the ground can be lifted and heeled in a corner of the garden to clear the way for sowing new seed during the next few weeks.
Parsnips require a longer growing season than other root crops. Any time from now until the first week in October will give seedlings the good start they need.
Poorly drained soil can be improved by pouring about 1cm of sand in the bottom of the seed drills. Cover the seed with more sand. Avoid sowing parsnips in recently manured ground or they will develop forked roots.
Add garden lime (30g/sq m) and a dusting of superphosphate before sowing. Parsnip seed quickly loses its vitality, so fresh seed should be bought each year.
Parsley is best sown in a position accessible in all weather. The herb can be sown now and likes a soil rich in organic material and slightly acidic.
French beans, sweet corn and salad plants can be sown under cloches or old windows. Place the covers in position for at least three weeks to warm the soil before sowing tender crops. This method can also be used to sow cabbages, cauliflowers, lettuce and silverbeet earlier than in open ground.
Jerusalem artichokes require a long season of growth and, if not already planted, should be put in as soon as ground can be prepared. Peas should be sown in small quantities. Little and often gives pea crops over a longer period and avoids the problem of them all being ready at once and going to waste.
Silverbeet from autumn sowings will respond to a weekly application of liquid manure and a fortnightly pinch of sulphate of ammonia sprinkled around the roots and hoed in.
Flowers
In warmer districts, hardy annuals can be sown where they are to flower. As with all seeds, the trick is to have the soil well prepared before sowing. Once seedlings appear, thin them out to prevent overcrowding.
Hardy, prolific and reliable flowers include alyssum, calendula, coreopsis, candytuft, cornflower, clarkia, godetia, Californian poppy (Eschscholtzia), larkspur, linaria, linum, nightscented stock (Matthiola bicornis), mignonette, love in a mist (nigella), pansy and viscaria.
Nasturtiums flower all summer in full sun or partial shade. They do well in poor soil but are frost tender so should not be planted out until the danger of frost has passed.
Modern varieties such as Black Velvet, Empress of India, Peach Melba, Whirlybird types and the semidouble Salmon Baby are more compact than older trailing types and do not take off across the garden.
Perennials to raise from seed from now until the end of October include granny bonnet (aquilegia), dianthus, dahlia, delphinium, gaillardia, geum, gypsophila, hollyhock, lupin, penstemon, polyanthus, pyrethrum and viola.
These will all flower within 12 months and some will bloom in their first season.
Start them in trays of seedraising mix, then plant them in the open garden when they have made some growth. They can be transplanted into their permanent positions in autumn.
Fruit
Peach tree leaf curl attacks peach, nectarine and almond trees. Active and damaging in late spring and summer, it should be treated now.
Disease-causing fungus spores overwinter in the buds and bud scales of the host plant. They spread rapidly once the leaves appear, distorting them with a wrinkled, red appearance.
An early spring fungicidal spray can control attacks. Use limesulphur (1:30 spray to water) or a Bordeaux mixture applied at the end of this month, just before the buds begin to open. Or spray with copper oxychloride (25g powder to 5 litres water) before the buds open.
Do not use sprays on hot, sunny days as they may cause scorching.
