Family: Chenopodiaceae
Genus and Species: Spinacia oleracea
Climate
Spinach is a cool season crop that likes damp conditions. Spinach is one of the first greens up in the spring. Sow spinach seed in a sunny spot in the fall or spring for a spring harvest. Spinach prefers partial to full sun. But can't tolerate hot weather.
Soil
Spinach loves an organically rich soil and well drained beds. Prepare the bed by amending the soil with compost or well-rotted compost. Muck soils are best as they provide spinach with the necessary organic matter and high, uniform, moisture content. A pH of 6.2 to 6.9 is optimum. Spinach has a deep taproot so cultivate the soil to at least 12" prior to planing spinach seed.
Spacing
Spinach plants should be 3" apart in rows 12" to 18" apart in beds at least 2' wide. Spinach is an easy plant to grow and spacing can be adapted to suit your needs. If you plan to sow spinach seeds often for an ongoing harvest, use a tighter spacing of 1" between spinach plants.
Direct Seeding
Spinach seed can be direct sown into the garden in fall or in the spring as soon as the soil can be worked. Rake the soil and plant spinach seeds 1/2" deep. Thin spinach to one seedling every 3" or so.
Seeding For Transplants
Sow spinach seeds indoors 3-4 weeks before the last frost. Plant spinach seeds 1/2" deep in flats or cell trays (1-2 spinach seeds per cell). Once spinach seedlings have 2 pairs of true leaves, thin to one spinach plant per cell or inch.
Germination
These seeds germinate best in soils around 65°F-70°F.
Germination will take 7-14 days.
Transplanting Into the Garden
Transplant spinach starts as soon as soon as soil can be worked. While spacing is not that important, aim for 2"-3" between plugs.
Watering
Spinach needs to be evenly moist throughout its growing season. Use of a straw mulch on the spinach beds will help retain soil moisture.
Harvesting
Spinach is ready to harvest when the spinach leaves are big enough to pick.
Harvest spinach by either cutting the leaves away from the spinach plant or by pulling the whole spinach plant out.
Post-Harvest Handling
Spinach leaves benefit from cooling immediately after harvest. Wash the spinach leaves in chilled water (hydro cooling).
Storage
Spinach leaves should be stored at 32° and 95% to 100% relative humidity. Spinach leaves are quite perishable and are normally marketed or eaten promptly. Spinach leaves can be stored 10-14 days.
Spinach is sensitive to ethylene gases so do not store it with fruits and vegetables that produce ethylene gas.
Diseases
Anthracnose, Spinach Blight, Damping Off, and Downy Mildew.
Pests
Flea Beetles, Crown Maggots, Leafhoppers, Loopers, Army Worms, Aphids, Leaf Miners, and Slugs
Comments
Use a sharp pair of scissors to thin spinach seedlings so as not to disturb the remainins spinach plants.
References
Bradley, F. M. and Ellis, B. W.(Ed.). (1992), Rodale's All-New Encyclopedia of Organic Gardening: The Indispensable Resource for Every Gardener, Emmaus, Pennsylvania: Rodale Press.
Oregon State University, Spinach , Commercial Vegetable Production Guides, Last modified 2003-01-06, http://oregonstate.edu/Dept/NWREC/spinach.html, Accessed 2003-7-18
Smith, E.C. (2000), The vegetable gardener's bible: discover Ed's high yield W-O-R-D system for all North American gardening regions., Storey Books: Pownal, VT.
Johnny's Selected Seeds (2002), "Spinach", Johnny's Selected Seeds.