Autumn the time for garden maintenance

Vegetables
Garden maintenance is important at this time of the year. Hoe regularly between rows to control weeds and maintain a good texture (tilth) of the soil. Small weeds can be left on the ground but any with flower heads should be put in the compost bin as many will make a last-ditch attempt and produce seeds on severed stems.

Clear away remnants of cabbages, lettuces and other crops. Left in the ground, stems keep drawing nourishment from the soil, which is wasteful, but in the compost bin they add an important green element.

Broccoli, which can take up to four months from planting out to maturity, can be sown now for late winter and spring use.

Spinach, turnips and onions can be sown.

Brown onions generally do better in the South if sown in autumn then left to stand over the winter. Perfect Keeper and Pukekohe Long Keeper are recommended varieties. When thinned in October, discards can be used like spring onions.

Late-sown beetroot, carrots and turnips will need thinning.

Leeks need to be kept thoroughly watered. If rotted poultry manure is mulched around the plants first, liquid manure will be created, acting as a stimulant. However, this does tend to attract flies.

A light sprinkling of salt on sandy soils will also stimulate growth but, as always, salt should be treated with some caution. Excessive potash fertiliser can increase the salt content in soil, so if in doubt, leave it out.

Parsley sown now should be ready for spring and next summer. Soaking the seed for a few hours in warm water will help germination. As seedlings appear, thin them ruthlessly to prevent overcrowding.

Keep making small sowings of mesclun mix for salads and Oriental vegetables such as pak choi and tatsoi for stir-fries to ensure a regular supply. Mesclun mixes, which are eaten at the leaf stage, include up to eight vegetables and are ideal for small households that find full-grown lettuces too big. Rhubarb flower stems must be removed to prevent them sapping the strength of the plants. The same is true of sea kale, another perennial vegetable that is making a comeback. Unless they are being saved for seed, trim seed heads from herbs such as sage, parsley and thyme.

Flowers
Plan now for next summer's flowers by sowing alyssum, Iceland poppies, cornflower, larkspur, Scabious, Antirrhinum and Clarkia.

Sow in well-prepared, permanent positions, thin to a few centimetres apart when seedlings appear and look forward to a fine show between spring-flowering bulbs and the later summer annuals.

Carnations can be increased by layering, a good way of getting more plants of favourite colours. Layering is a method by which new roots are developed before a cutting is removed from a plant, so the shock of transplanting is reduced.

Ground layering is done by bringing a stem down to soil level and holding it in place with a wire loop or heavy stone. Before putting the stem in position, make a cut about 1cm long and a third of the way through the stem.

The soil under and over the cut stem should be rich, with some fine gravel added. Patience is the secret of success with layering, especially if shrubs such as rhododendrons are layered, as they can take a year or more to form good root systems.

Spring bulbs will be appearing in garden centres, so buy early to get the best selection.

Daffodils should be the first to go into the ground. Any bulbs that have been in the same spot for three or more years may need to be lifted, divided and replanted in replenished soil.

Compost dug in well and added bone dust helps. Although the usual advice is to plant bulbs in twice their depth of soil, in fact, soil type should be the guide. In light, sandy soil, plant bulbs at three times their depth and half that in heavier ground. Tulips like lime in the soil, whereas daffodils prefer a slightly acid soil.

Fruit
Strawberries should be flowering now for their second crop next month. Although the autumn crop is generally smaller, these berries are often the best flavoured as they have a higher sugar content. Old varieties, unsuitable for commercial growers because the fruit is too soft to travel well, can be sought out by gardeners more interested in taste than size.