Spinach in the garden is a sign of spring.
Spinach is a source of Vitamin A. It is rich in iron, calcium, and protein. Spinach can be grown as a spring and a fall crop. Crinkled-leaved varieties tend to catch soil during rainfalls. Plant a plain-leaved variety to avoid "gritty" spinach when chewed.
When to Plant
The first planting can be made as soon as the soil is prepared in the spring.
- If the soil was prepared in the fall, seeds can be broadcast over frozen ground or snow cover in late winter and they will germinate as the soil thaws.
- Plant successive crops for several weeks after the initial sowing to keep the harvest going until hot weather.
- Seed spinach again in late summer for fall and early winter harvest.
- Chill seeds for summer or fall plantings in the refrigerator for 1 or 2 weeks before planting.
- In southern locations, immature spinach seedlings survive over winter on well-drained soils and resume growth in spring for early harvest.
- With mulch, borderline gardeners should be able to coax seedlings through the winter for an early spring harvest.
- Spinach can be grown in low tunnels, sunrooms, or protected cold frames for winter salads.
Spacing & Depth
- Sow 12 to 15 seeds per foot of row.
- Cover 1/2 inch deep.
- When the plants are one inch tall, thin to 2 to 4 inches apart.
- Closer spacing (no thinning) is satisfactory when the entire plants are to be harvested. The rows may be as close as 12 inches apart, depending upon the method used for keeping weeds down.
- In beds, plants may be thinned to stand 4 to 6 inches apart in all directions.
- Little cultivation is necessary.
Spinach grows best with ample moisture and a fertile, well-drained soil. Under these conditions, no supplemental fertilizer is needed. If growth is slow or the plants are light green, side-dress with nitrogen fertilizer.
Cucumber mosaic virus causes a condition in spinach called blight.
Downy mildew and other fungal leaf diseases are a problem, especially in seasons that are wet, humid, or both. Some resistance is available through variety selection. Raised beds create excellent air and water drainage in the spinach bed, which also helps prevent infections.
The plants may be harvested whenever the leaves are large enough to use (a rosette of at least five or six leaves). Late thinnings may be harvested as whole plants and eaten.
- Cut the plants at or just below the soil surface.
- Spinach is of best quality if cut while young.
- Two or three separate seedings of short rows can provide harvest over an extended period.
Some gardeners prefer to pick the outer leaves when they are 3 inches long and allow the younger leaves to develop for later harvest.
- Harvest the entire remaining crop when seed stalk formation begins because leaves quickly deteriorate as flowering begins.
- If harvesting a winter crop grown in a protected location, pick when temperatures are above freezing.
Questions & Answers
Q. What causes spinach to develop flower stalks (seed stalks) before a crop can be harvested?
A. Spinach bolts quickly to seed during the long days in late spring or summer. Warm temperatures accelerate this development. Varieties that are "long-standing" or slow to bolt are best adapted for spring planting.
Q. What causes yellowing, stunting, and early death of plants?
A. These conditions are caused by blight disease (cucumber mosaic virus). Grow resistant varieties.