English spinach (Spinacia oleracea) has soft leaves on slender stems, while silverbeet has firm crinkly leaves with well-defined ribs and veins. Spinach (or chard) is an annual but Silverbeet is a biennial.
Spinach likes good drainage, a rich soil with plenty of compost and will tolerate light shade. Try to remove stones and weeds and turn the soil well before planting.
Spinach is best suited to cool climates and (in the right spot) will be productive in Canberra throughout winter and spring. You can use a cloche to protect young seedlings from frost in late autumn and to protect mature plants from the heat in late spring.
Spinach can be successfully grown from seeds or seedlings. Germination of seeds is possible in temperatures as low as 5 degrees C, although 10-16 degrees is preferable. Sow seeds 1cm deep either directly or in punnets. Each seed produces two or three seedlings and it is suggested that these clumps be planted together.
Seedlings should be planted or thinned to around 30cm apart. Spinach does not respond well to root disturbance, so plan your final position in advance.
Weeding and mulching are important to reduce competition and to create stable (cool and moist) growing conditions.
Spinach grown in poorer soils will benefit from application of plentiful compost mulch.
Pick individual leaves as you need them, from the outside of the plant, but make sure you leave enough for the plant to be able to photosynthesise. It is better to cut (rather than pull) the leaves to avoid damage to the root system.
Alternatively, cut the whole plant once it’s large enough to use. Harvest can usually start 4-6 weeks from planting.
The biggest problem with spinach is its tendency to bolt to seed as soon as conditions become even slightly unfavourable. This is particularly an issue in late spring when days become longer and temperatures increase.
Spinach also tends to bolt under water or nutrient stress. Mature spinach plants don’t suffer from too many pests, but can be occasionally attacked by slugs and snails.