How to Grow Spinach
Spinach is one of the few vegetables with beets and chard that prefers a neutral to alkaline soil (pH 7.0 or above). If your garden soil is sandy and acid, be sure to get a lime recommendation based on a soil test before planting spinach. Spinach is also a heavy feeder. Start by working 2-4 pounds of a complete fertilizer per 100 square feet into the soil at planting time and then side-dress every two weeks or as necessary to keep the plants growing vigorously. Be sure to keep fertilizer 4-6 inches from the base of the spinach plants so as not to burn the roots and water thoroughly immediately after fertilizing.
There is no such thing as putting too much compost in garden soil. Mix at least 2-4 inches of compost in the row before planting. Commercial compost is sometimes little more than slightly decayed wood chips. Check to see that the raw material used to make the compost is mostly unrecognizable before buying it or better yet, make your own.
Spinach thrives in cool weather and short days so it's best to grow it in the fall for most gardeners. Northern gardeners can plant an early spring crop followed by another in midsummer to mature before the first hard freeze. In southern gardens spinach easily tolerates a light frost, especially if it is acclimated. In case of a sudden or hard freeze (below 28 degrees), old blankets or polypropylene frost blankets can save the day and prolong the harvest.
Plant spinach seeds an inch apart in rows 14-18 inches apart and cover the seeds with a 1/2 inch of soil. Keep the soil moist and after the seeds germinate thin them to stand 3-5 inches apart. Most gardeners like to do this in several passes to determine the strongest plants to save. Thinning is very important and you must be ruthless in the final analysis or you will have a congested row of plants that don't size up.
Spinach Plant History
Spinach is thought to be of Persian origin (modern-day Iran). It was introduced into Europe about 1000 AD It wasn't until after the eighteenth century that it began to be cultivated in the Netherlands, France, and England with the Spanish eventually bringing it to the Americas.
Should I Plant Spinach Seeds Or Plants?
Most gardeners start with seeds but transplants are often available at local nurseries. Germinating the seeds in the heat of late summer/fall can be a real challenge. The best soil temperatures for rapid germination (6-7 days) are between 68 and 86 degrees F. Keeping the soil constantly moist and covering the row with fiber row cover will help to cool the soil and get the seeds up. Be sure to remove the row cover as soon as the seedlings are visible. If it's still too hot use hoops made from 1/2 inch polyethylene irrigation tubing to lift the row cover off of the small seedlings. A final spacing of 3-5 inches is best for most varieties. So either transplant them directly to this spacing or thin them.
How Do I Cultivate Spinach Plants?
Spinach is grown commercially on deep, loam soils. If your garden soil is acid (pH below 7), then be sure to lime the soil based on a soil test to raise the pH to 7.0. Many gardeners opt for raised beds, 6-8 inches above the existing soil, especially if they have a heavy clay soil to deal with. Working 2-4 inches of compost into the soil prior to planting is always a good idea and while you're at it incorporate 2 pounds of a complete fertilizer per 100 square feet.
Make sure the plants are adequately spaced or you will end up with lots of very small leaves and don't be afraid to side-dress the row with nitrogen to encourage a continual production of leaves. Ammonium sulfate at 2 tablespoons per foot of row should keep the spinach producing all season long if applied every two weeks or as needed. Similarly, spinach needs lots of water but it also needs good drainage. Finally, just harvest a few leaves at a time from each plant. This will allow the plants to continue producing all season.
Spinach Plant Growing Tips
The key to success with spinach begins with getting the plants off to a good start. Plant the right varieties in a rich, organic soil. Supply lots of moisture and cool the soil (especially with late summer plantings) and don't be shy about fertilizing. Side-dressing with a nitrogen fertilizer will work and so will foliar applications of fertilizer like Dyna-Gro. Check out the Organica Plant Growth Activator and Marine-Gro products, too. Vigorous spinach is tasty spinach.
Spinach Plant Insects & Diseases
Aphids or plant lice are fond of spinach. Usually a high-pressure water spray will knock them off or try one of the organic sprays like Burpee's K+Neem. Check with your local Cooperative Extension Agent for other recommended pesticides.
Caterpillars love spinach, too. Use one of the biological worm sprays (Bacillus thuringiensis) to take out these pests without hazard to people, pets and beneficial insects.
Diseases are also a threat to spinach. White rust, blue mold (downy mildew) and the soil-borne disease fusarium wilt are the primary pests in this category. White rust is a common problem during cool, humid conditions. If only a few leaves are infected just remove them. Where this disease is a common problem, as it is in many areas of the South, check with the Extension Service for recommended fungicides.
Blue mold can also be treated by removing infected leaves (look for yellow spots on top of the leaf and a grayish-blue mold on the bottom of the leaf) or use a recommended fungicide.
Rotating spinach with unrelated crops for at least three years is the best control for fusarium wilt.
Spinach Plant Recipes & Storage
Fresh spinach is wonderful with blue cheese or ranch dressing, maybe a little bacon, hard-cooked egg, etc, etc. It's also great sautŽed with a little bacon grease, green onion and a vinegar hot pepper sauce. Spinach makes a great quiche and also works well in an omelet.