Spinach is an excellent source of beta cortene, vitamin C, E, and K, potassium, iron, sulphur, sodium, folic acid and oxalic acid. It contains more protein than most vegetables. Spinach is one of the vegetables with the highest amount of chlorophyll, a fat-soluble substance that stimulates hemoglobin and red blood cell production.

Chlorophyll is known to have a chemical formula remarkably similar to that of hemoglobin, and it is said that the ingestion of chlorophyll will raise hemoglobin in blood without increasing the formed elements.

In plants, chlorophyll carries carbon dioxide as food to cells and oxygen back as waste to be discharged from the system. In animals, hemoglobin carries oxygen as food to cells and exchanges it for carbon dioxide which is then discharged as waste from the system.

So plants like spinach that are high in chlorophyll support the liver in detoxifying and cleansing the blood. With spinach, the effect is reinforced by its considerable amount of sulphur. Sulfur is an acid-forming mineral that protects the protoplasm of the cells, disinfects the blood and helps body resist bacteria. Folic acid is needed to form red blood cells and support the formation and function of white blood cells.

The exceptionally high antioxidant property of spinach is due to carotenoids, beta carotene and lutein, which are three to four times higher than in broccoli, for example. These naturally occurring fat-soluble pigments are most effective when eaten with some fat. Spinach also has plenty of potassium, which supports a healthy nervous system, aids proper muscle contraction, stabilises blood pressure, regulates the transfer of nutrients through cell membranes and, together with sodium, controls the water balance of the body.

While spinach is known for its high iron content, recent studies have shown that the iron contained in spinach is not easy for the body to assimilate and only a very low percentage is used. The relatively high amount of oxalic acid in spinach interferes with the absorption of iron and calcium into the blood.

When eaten in large amounts, spinach could damage already impaired kidneys: oxalic acid removes calcium from the blood in the form of calcium oxalate, and calcium oxalate obstructs the kidney tubules. The fairly high concentrate of nitrogen compounds in spinach can be reduced up to 70 per cent by blanching the vegetable.

Climate and soils: This is an important vegetable of Rabi season and requires a cool and moist climate. Low temperature and high humidity helps in the development of succulent, tenders mild flavoured foliage and quick growth. The plant prefers sunshine.

For seed development and maturity, plant requires long and warm days. Spinach germinates best at soil temperature below 10-12c. At high temperature, the seed fails to germinate because they enter into a dormant state which continues until the temperature again falls below 10-12oc.

Spinach can be grown successfully on a variety of soils, but a fertile sandy loam high in organic matter is preferred. The use of cover crops and green manure crops is recommended to maintain the soil organic matter. The soil pH should range between 6.4 to 6.8. Spinach is very sensitive to acid soils, thus a soil test prior to planting this crop should be made. Low germination, yellowing and browning of margins and tips of seedling leaves, browning of roots, general slow growth and even death of plants, may indicate that the soil is too acid. If the pH is too high, leaves may have a yellow colour referred to as chlorosis.

Land preparation: A well-prepared seedbed that is free of large clods permits precision planting with rapid and uniform emergence of spinach seedlings. Uniform depth of seeding is critical when using pre-plant-incorporated herbicides because if spinach seeds are planted too deeply, seedlings may be killed by herbicide. Well-prepared seedbeds also permit proper and accurate incorporation of pre-plant-incorporated herbicides, leading to improved weed control and reduced phytotoxicity to seedlings. In situations where cultivation can be used, uniform beds with level bed tops are essential

Irrigation: Spinach requires abundant moisture to insure a high quality product. An application of one inch of water every seven to ten days, when rainfall is inadequate, is recommended. Keep soil moist until seedlings have emerged.

Time of sowing: Winter spinach is best when sown in August. Summer spinach can be started in February and needs lot of water

Seed rae and varieties: There are two varieties of spinach in Pakistan. Local Sindhi and prickly heat. Around eight to ten seed per acre is recommended. Seeds are broadcasted on the flat beds or in ridges and are mixed with fully prepared soil sans pressed with some hard material immediately after sowing seed, irrigation water is applied.

Fertilisers: Spinach requires a high level of fertility, especially nitrogen. Early spring spinach may require larger quantities of fertiliser than fall crops. Per acre requirements on sands and sandy loams are 85 to 120 lb N; 75 to 85 lb P2O5; and 85 to 150 lb K2O. On heavier clay soils, 50 lb/acre of each nutrient should be adequate. Fertilizer is often broadcast and worked into the soil prior to seeding. If the fertilizer is banded at seeding, it should be placed along each side of the rows 2 to 3 inches below the level of the seed .

Weed control: A healthy, vigorous crop provides substantial competition that suppresses weed growth and acts as part of the weed control programme. Therefore, proper fertilisation, irrigation, and insect and disease control measures promote good crop growth and compliment other weed control measures.

Hand-weeding is an expensive component of crop production budget. If a weeding crew is sent into a field before the harvest when weeds are mature, weed removal is typically slow and expensive. Ideally, good cultural practices and careful use of herbicides will result in minimal hand-weeding requirements.

After planting the crop, there are two periods in which herbicides may need to be applied, depending on the weed species present. Post plant treatments are applied after planting but before the first irrigation and the emergence of crop; post emergent treatments are applied when spinach is in the seedling stage or older to the side of the row; fertiliser should never come in contact with the seed.

Insects: Spinach aphid and leaf miner are the two predominant insect pests of spinach.

Diseases: Downy mildew (blue mold), bacterial soft rot, fusarium wilt, cucumber mosaic virus, carpospores spot, white rust and heterosporium spot can all be problems in spinach production

Marketing and storage: Spinach is sold loose, in pre-packaged bags, or frozen. Fresh spinach loses much of its nutritional value with storage of more than a few days. While refrigeration slows this effect to about eight days, spinach will lose most of its folate and carotenoid content, so for longer storage it is frozen, cooked and frozen, or canned. Storage in the freezer can be for up to eight months.

Harvesting and yield: The crop is ready for cutting with in six to eight weeks after sowing. The cutting is done 2cm above the ground level when plants have put five to six leaves. New foliage is cut later with three to four cuttings.