Spinach is the most important pot herb or green grown in the U.S. It is included in most home garden plantings. Spinach is rich in vitamin A and high in ascorbic acid, riboflavin plus some thiamine. It is also rich in iron and calcium.
Spinach thrives best during relatively cool weather. It is what we know as a short-day plant and, consequently, when grown during the long light and high temperatures of summer, develops a seed stalk very quickly. In the North it is therefore grown as a spring and fall crop and during late fail, winter and early spring in the South.
There are many varieties listed by seeds men; some of which have curly, crinkled or savoyed leaves, while others are a lighter green with fiat leaves.
The lighter sandy and silt loam soils are preferred. Spinach is sensitive to both an alkaline and an acid soil. Soils having a pH range of 6.0-7.0 are excellent. Apply 20-30 lbs. of a 5-10-10 fertilizer per 100 sq. ft. prior to planting and then side dress with several pounds of nitrate of soda when the plants have a leaf spread of 2-3 in. Plant 1 oz. of seed per 100 ft. row and space the rows 12-15 in. apart. Plant only as much as can be used in 4-6 days and make 3-4 sowings at weekly intervals. The last planting should not mature later than mid-June or July. Fail plantings should start about Aug. Cultivation should be shallow and only sufficient to control weeds.
Spinach can be harvested as soon as 5-6 leaves have fully developed by cuing the top root just below the lowest leaves.
Spinach Diseases and Insects
Spinach blight or yellows, is a virus disease spread by aphids. Affected plants show a yellowing of the leaves and stunted, twisted plant growth. Control aphids and use resistant varieties such as ‘Virginia Blight Resistant’. This disease is most common in the fall and winter plantings. Blue mold is a disease showing yellow spots on the upper surface of the leaf and downy purple or blue mold on the underside. It is most prevalent during cool, high-humid weather. No specific control except good drainage, weed control and crowding of plants. Aphids, green soft-bodied insects usually most common in warmer weather, controlled with nicotine sulfate or a malathion dust. Be sure the spray material covers the underside of leaf.
New Zealand Spinach, Tetragonia expansa, is not a true Spinach. The plants are much branched, spreading from 21-24 ft. across and 1-2 ft. in height. The leaves are thick, dark green and are used in the same manner as true Spinach. The seeds are enclosed in a hard, rough pod.
New Zealand Spinach thrives in hot weather and, therefore, is an excellent substitute for ordinary Spinach for summer culture.
The seed germinates slowly and, therefore, may be treated for several hours in hot water prior to sowing. Some gardeners prefer to start the plants in a hotbed and then transplant them into the garden when 2-3. in. tail. Normal planting distance is 3 ft. between rows and about 2 ft. in the row. Actually, only 5-6 plants are sufficient for the average family. Cultural practices are similar to those for ordinary Spinach.
The tips of the branches are cutoff. New shoots will develop so that a continuing supply will be available throughout the entire season. Good growth is essential to develop soft, succulent and tender growing points.
A prostrate, succulent annual, grown as a vegetable, native to Japan, Australia, New Zealand and South America, especially for its tender young stems and leaves which are cooked and eaten like Spinach. Plants are taller, more vigorous and tougher than Spinach but it makes a good substitute for growing in hot weather. Leaves are alternate, flowers few, small and without petals, leaves ovate, often triangular, up to 5 in. long.