There are three types of spinach and they all pretty much taste the same. The big difference between them is the way that they look. The three basic types of spinach are:
Savoy spinach has dark green crinkled leaves, grows "flatter" compared to other spinach, tends to be more cold-hardy, and becomes sweeter and crisper after a frost.
Flat-leaf (also called Smooth-leaf) spinach grows more upright, and because the leaves are flat, they are easier to wash. This type is often grown for canned and frozen spinach, as well as soups, baby foods, and processed foods.
Semi-savoy is a hybrid between Flat-leaf and Savoy spinach, with leaves that are not as crinkled as Savoy yet not as smooth as the Flat-leaf varieties. It is grown for both fresh marketing as well as processing.
Spinach has a high nutritional value, especially when eaten raw or lightly steamed. It is an excellent source of iron, calcium, potassium, and dietary fibre. It is also a rich source of vitamins A, E, C, K, and the B Vitamins, including Riboflavin (vitamin B2) and folate (folic acid or folate is a B vitamin.) Cooking spinach with parsley helps the body to absorb the iron in spinach.
Spinach can be used in treating lung inflammation. The seeds can be used as a laxative and for treating breathing difficulties and liver inflammation.
Spinach has a mild flavour that won't overpower already-flavourful recipes. It has a high nutritional value, especially when eaten raw or lightly steamed or sautéed; making it an easy, healthy addition to many meals. Tender, fresh spinach is delicious in salads, and great with pasta, soups, quiches, casseroles, side dishes and dips. Try baking it in bread and making it into pies with feta cheese. It pairs brilliantly with soft cheeses like ricotta and feta in lasagne and spanakopita (Greek Spinach Pie.) If you have a bountiful harvest, spinach can even be canned or quick frozen. Cooking spinach with parsley helps the body to absorb the iron in spinach.
In the Garden:
The dark green colour and handsome texture of savoy varieties are great for edible landscaping.
Pyrethrum is a good insect repellent and will keep slugs at bay. Spinach grows well with cabbage, kohlrabi, broccoli, beetroot, onions and beans.
Cultivation and Harvesting:
Spinach must not be confused with the popular Swiss chard. True spinach produces fine quality leaves but requires cool growing conditions or it will run to seed quickly. Also, seeds will not germinate well in warm weather, germinating best in soil temperatures between 7°C to 24°C. Although spinach will grow in temperatures ranging from 5°C to 24°C, growth is most rapid at 15 to 18°C.
Because spinach does not transplant very well it is best to sow seeds directly into garden beds in late summer or autumn. When growing spinach, the trick lies in making it last as long as possible, especially in the spring, when lengthening days shorten its life. Early spring plantings can produce crops as long as the temperatures do not climb too high, too early in the season. Spinach grows well on a variety of soils, but thrives in fertile, sandy loams with high organic content. Heavier soils can still be quite productive as long as they drain well and are irrigated with care. Spinach does not like overly acid soils and the optimum soil pH is 6.2 to 6.9. Add agricultural lime to amend acid soils. You should suspect that your soil is too acid if germination is poor and leaf tips and margins are yellow or brown.
Spinach must grow quickly to produce large, succulent leaves and it is essential to prepare the beds very well by digging them over thoroughly and adding lots of compost and even some old manure, plus a dressing of organic 2:3:2 before planting. Make furrows and sow the seeds as thinly as possible, allowing 30cm between rows. Thin the seedlings to allow 20 to 30cm between seedlings and mulch the soil lightly. It is vital that you water your crops regularly, never allowing the beds to dry out completely, but not drowning them either! Feed every 2 weeks with a balanced organic fertiliser that is high in nitrogen like 3:2:1; and keep the beds weed free.
You should be able to start harvesting after 8 to 10 weeks and each plant will produce leaves for about 4 weeks. Leaves can be harvested gradually by cutting the outside leaves as required and allowing the centre to continue growing, or the whole plant can be harvested at once. For successive crops sow seed every 3 to 4 weeks. Harvest the whole crop in late spring before the weather warms up and the plants go to seed.
Allow a couple of plants to go to seed if you wish to collect seed for next season. Harvest the seed when the flowers on the plants dry out. Once the plant has dried out the clusters of seed will fall out of the place where the flowers once were. If you store the seeds in a cool dry place, they will last for up to 4 years.
Pests & Diseases:
If grown in the correct season and with the right care, spinach is easy to grow. Spinach leaf miner and aphids are the most frequent pests of spinach. Weed control in the beds goes a long way to controlling these pests. Also watch out for leaf eating bugs, snails and slugs. Diseases that attack plants are downy mildew (a mildew that may appear during cool, moist weather) and white rust (which causes white spots on the leaves).
Problems: Rot can occur if the soil does not drain well. If grown when the temperatures are too high, spinach tends to bolt, just like lettuce.