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Amaranthaceae FAMILY

Spinacia oleracea

Spinacia oleracea

Edibility
3/5
Medicinal
2/5

Safety & Hazards

The leaves of most varieties of spinach are high in oxalic acid[1]. Although not toxic, this substance does lock up certain minerals in a meal, especially calcium, making them unavailable to the body. Therefore mineral deficiencies can result from eating too much of any leaf that contains oxalic acid. However, the mineral content of spinach leaves is quite high so the disbenifits are to a large extent outweighed by the benefits. There are also special low-oxalic varieties of spinach that have been developed. Cooking the leaves will also reduce the content of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[2].

Cultivation Details

HabitAnnual
GrowthFast

Plants grow best and produce their heaviest crop of leaves on a nitrogen-rich soil[3, 4, 5]. They dislike very heavy or very light soils[4]. They also dislike acid soils, preferring a neutral to slightly alkaline soil[5]. Plants require plenty of moisture in the growing season, dry summers causing the plants to quickly run to seed[6]. Summer crops do best in light shade to encourage more leaf production before the plant goes to seed[6], winter crops require a warm dry sunny position[7, 6]. Young plants are hardy to about -9°c[5]. Spinach is often cultivated for its edible leaves, there are some named varieties[8, 9]. These varieties can be grouped into two main types as detailed below:- Forms with prickly seeds. These are the more primitive forms. Their leaves are more lobed and they are in general more cold tolerant and also more resistant of summer heat[10]. They were more often used to produce a crop in the winter[5, 10]. Forms with round seeds have been developed in cultivation, These have broader leaves, tend to be less cold hardy and were also more prone to bolt in hot weather[10]. They were used mainly for the summer crop[5]. Most new cultivars are of the round seeded variety and these have been developed to be more resistant to bolting in hot weather, more cold tolerant, to produce more leaves and also to be lower in calcium oxalate which causes bitterness and also has negative nutritional effects upon the body[10]. Some modern varieties have been developed that are low in oxalic acid. Edible leaves can be obtained all year round from successional sowings[5]. The summer varieties tend to run to seed fairly quickly, especially in hot dry summers and so you need to make successional sowings every few weeks if a constant supply is required. Winter varieties provide leaves for a longer period, though they soon run to seed when the weather warms up. Spinach grows well with strawberries[11, 12]. It also grows well with cabbages, onions, peas and celery[13]. A fast-growing plant, the summer crop can be interplanted between rows of slower growing plants such as Brussels sprouts. The spinach would have been harvested before the other crop needs the extra space[5]. Spinach is a bad companion for grapes and hyssop[13].

Propagation

Seed - sow in situ from early spring to early summer for a summer crop. Make successional sowings, perhaps once a month, to ensure a continuity of supply. The seed germinates within about 2 weeks and the first leaves can be harvested about 6 weeks later. Seed is sown in situ during August and September for a winter crop. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Spinacia+oleracea>

Pollinators

Wind

References

  1. [1]Medicinal Plants of China — Duke. J. A. and Ayensu. E. S. · Reference Publications, Inc. · 1985 · ISBN 0-917256-20-4 ↩︎Details of over 1,200 medicinal plants of China and brief details of their uses. Often includes an analysis, or at least a list of constituents. Heavy going if you are not into the subject.
  2. [2]Encyclopaedia of Herbs and their Uses. — Bown. D. · Dorling Kindersley, London. · 1995 · ISBN 0-7513-020-31 ↩︎A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant.
  3. [3]New Vegetable Growers Handbook. — Simons. · Penguin · 1977 · ISBN 0-14-046-050-0 ↩︎A good guide to growing vegetables in temperate areas, not entirely organic.
  4. [4]The Gardener's Assistant. — Thompson. B. · Blackie and Son. · 1878 · ISBN - ↩︎Excellent general but extensive guide to gardening practices in the 19th century. A very good section on fruits and vegetables with many little known species.
  5. [5]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  6. [6]The Vegetable Garden. — Vilmorin. A. · Ten Speed Press · ISBN 0-89815-041-8 ↩︎A reprint of a nineteenth century classic, giving details of vegetable varieties. Not really that informative though.
  7. [7]RHS Dictionary of Plants plus Supplement. 1956 — F. Chittendon. · Oxford University Press · 1951 · ISBN - ↩︎Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaced in 1992 by a new dictionary (see [ 200 ]).
  8. [8]Fruits of the Earth. — Bianchini. F., Corbetta. F. and Pistoia. M. ↩︎Lovely pictures, a very readable book.
  9. [9]Cornucopia - A Source Book of Edible Plants. — Facciola. S. · Kampong Publications · 1990 · ISBN 0-9628087-0-9 ↩︎Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.
  10. [10]Vegetables — Phillips. R. & Rix. M. · Macmillan Reference Books, London. · 1995 · ISBN 0 333 62640 0 ↩︎Excellent and easily read book with good information and an excellent collection of photos of vegetables from around the world, including many unusual species.
  11. [11]Companion Plants. — Philbrick H. and Gregg R. B. · Watkins · 1979 · ISBN - ↩︎Details of beneficial and antagonistic relationships between neighbouring plants.
  12. [12]Companion Planting for Successful Gardening. — Riotte. L. · Garden Way, Vermont, USA. · 1978 · ISBN 0-88266-064-0 ↩︎Fairly good.
  13. [13]A - Z of Companion Planting. — Allardice.P. · Cassell Publishers Ltd. · 1993 · ISBN 0-304-34324-2 ↩︎A well produced and very readable book.
  14. [14]Sturtevant's Edible Plants of the World. — Hedrick. U. P. · Dover Publications · 1972 · ISBN 0-486-20459-6 ↩︎Lots of entries, quite a lot of information in most entries and references.
  15. [15]Plants Consumed by Man. — Brouk. B. · Academic Press · 1975 · ISBN 0-12-136450-x ↩︎Readable but not very comprehensive.
  16. [16]Glossary of Indian Medicinal Plants (Including the Supplement). — Chopra. R. N., Nayar. S. L. and Chopra. I. C. · Council of Scientific and Industrial Research, New Delhi. · 1986 · ISBN - ↩︎Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.
  17. [17]Flowers of Europe - A Field Guide. — Polunin. O. · Oxford University Press · 1969 · ISBN 0192176218 ↩︎An excellent and well illustrated pocket guide for those with very large pockets. Also gives some details on plant uses.