SpinachBotanical Name: Spinacia oleracea (LINN.)
Family: N.O. Chenopodiaceae Part Used: Leaves.
Habitat: The Spinach is an annual plant, long cultivated for the sake of its succulent leaves, a native of Asia, probably of Persian origin, being introduced into Europe about the fifteenth century.
Constituents: Spinach is relatively rich in nitrogenous substances, in hydrocarbons, and in iron sesqui-oxide, which last amounts to 3.3 per cent of the total ash. It is thus more nourishing than other green vegetables. It is a valuable part of the diet in anaemia, not only on account of its iron, but also for its chlorophyll. Chlorophyll is known to have a chemical formula remarkably similar to that of haemoglobin, and it is stated that the ingestion of chlorophyll will raise the haemoglobin of the blood without increasing the formed elements. The plant contains from 10 to 20 parts per 1,000 by weight of chlorophyll. During the war, wine fortified with Spinach juice 1 in 50) was given to French soldiers weakened by haemorrhage.
According to Chick and Roscoe (Biochem. Journal, 1926, XX, 137), fresh leaves of Spinach are a rich source of vitamin A, a small daily ration (0.1 gram and upward) encouraging growth and lessening or preventing xerophthalmia in young rats on diets devoid of fat-soluble vitamins. Spinach grown in the open in winter, spring or autumn possesses no antirachitic properties that can be demonstrated by the methods employed. Spinach leaves when irradiated with ultraviolet rays from a Hg vapour quartz lamp become powerfully antirachitic.
Boas (Biochem. Journal, 1926, XX, 153) found that the fresh leaves of winter-grown Spinach added to an experimental diet caused an even greater improvement in the wellbeing of rats and in the rate of growth than was caused by the addition of cod-liver oil. The weight of the skeleton was not, however, proportionally increased. The conclusion was drawn by Boas that winter Spinach contains an amount of vitamin D which isnegligible compared with its content of vitamin A.
The leaves contain a large proportion of saltpetre. The water drained from Spinach, after cooking, is capable of making as good match-paper as that made by a solution of nitre.
Cultivation: Spinach should be grown on good ground, well worked and well manured, and for the summer crops abundant water will be necessary.
To afford a succession of Summer Spinach, the seeds should be sown about the middle of February and again in March. After this period, small quantities should be sown once a fortnight, as Summer Spinach lasts a very short time. The seeds are generally sown in shallow drills, between the lines of peas. If occupying the whole of a plot, the rows should be 1 foot apart.
The Round-seeded is the best kind for summer use.
The Prickly-seeded and the Flanders kinds are the best for winter and should be thinned out early in the autumn to about 2 inches apart, and later on to 6 inches. The Lettuceleaved is a good succulent winter variety but not quite so hardy.
The first sowing of Winter Spinach should be made early in August and again towards the end of that month, in some sheltered but not shaded situation, in rows 18 inches apart, the plants as they advance being thinned and the ground hoed. By the beginning of winter, the outer leaves will have become fit for use, and if the weather is mild successive gatherings may be obtained up to the beginning of May.