Silverbeet (ht 30-50 cm) can be grown year-round in Sydney. It will grow in sun or part-shade. In summer, it will definitely do better in part-shade, as it will suffer in extreme heatwaves and bolt to seed, and may be more likely to suffer from diseases. It is a tall, robust plant with large, deep green leaves with a tough central white stem and prominent veins on the back of the leaves. It is often used in cooking as a substitute for English spinach. The so-called 'perpetual spinach' is, in fact, a green-leaf variety of silverbeet with short stems and large leaves that taste more like spinach than ordinary silverbeet. It is a very useful crop to grow at home as it doesn't run to seed in its first year as the other forms, giving a longer cropping period, and it should survive for a couple of years in the garden. It is more heat-tolerant than true spinach.
Swiss or rainbow chard is a form of silverbeet (Beta vulgaris subsp. cicla var. flavescens), with stems coloured golden-yellow, pink, orange or ruby-red, which look very decorative in the garden; one version has very dark green leaves, which look dramatic. Silverbeet can be picked leaf by leaf rather than harvesting the whole plant at once - gently pull the outer leaves from the plant, as cutting them off leaving a piece of the stem behind can exacerbate disease problems. Silerbeet can be eaten raw in salads or used in many cooked vegetable dishes. Note that silverbeet, although to a lesser extent, than English spinach, contain oxalate (oxalic acid), to which some people are sensitive, in which case, excessive consumption of the leaves should be avoided.
Silverbeet needs good soil, enriched with compost or other organic matter. It can be raised from seed planted in early autumn or via seedlings in a punnet. Space the plants about 30-40 cm apart. Water regularly and apply liquid fertilisers on a weekly basis to keep them growing well. A regular seaweed spray can help control rust and leaf spot. Silverbeet has many nutritional benefits. It is high in fibre and is a good source of vitamins A, K and C, as well as minerals including potassium and magnesium.