These freshly picked spinach leaves are nearly perfect.
These spinach plants grow close together so that they can be thinned as they are harvested.
When spinach begins to bolt, it tastes bitter and is ready to be pulled. This is what the plants look like when they grow tall to bloom.Spinach is a cool-weather vegetable related to beets and Swiss chard. A fast-growing plant, it yields many leaves in a short time in the mild weather of spring and fall. The trick lies in making spinach last as long as possible, especially in the spring, when lengthening days shorten its life. Although it prefers full sun, spinach is one of the few vegetables that produce a respectable harvest in partial shade.
Soil, Planting, and Care
Spinach grows most quickly in well-drained soil rich in organic matter such as compost or composted manure and with a pH of 6.5 to 7.
In order to grow spinach twice a year, plant it about four to six weeks before the last frost in the spring, and again six to eight weeks before the first frost in the fall. Bonnie transplants arrive at your local retailer in time for both spring and fall plantings. Plant transplants at the space recommended on the label. If you don’t have the label, a good general spacing is about 12 to 18 inches apart; this gives leaves room to reach full size.
For the most tender leaves, encourage spinach to grow fast and without interruption by using nitrogen-rich soil amendments such as blood meal, cottonseed meal, or composted manure worked into the soil. Or, apply a timed-release vegetable food such as 14-14-14 according to label directions. Work the fertilizer thoroughly into the soil before planting. You may also use liquid starter fertilizer such as fish emulsion or 20-20-20 at planting for a boost. Dilute according to label directions.
In the spring, plants will grow tall and bloom (called bolting) as soon as the days are longer than 14 hours. Heat also speeds up bolting, since spinach prefers temperatures between 35 and 75 degrees.
Our Correnta variety is slow to bolt; in trials at Oregon State University’s research farm in Corvallis, it lasted longer than others without bolting. Folks who don’t have the luxury of mild weather will appreciate Correnta’s extension of spring harvests throughout the country.
Because it bolts in the lengthening days of spring, spinach is an especially popular crop for fall, when days are short and cool. Plants are very cold hardy, tolerating temperatures as cold as the teens to low 20s once they are well established. This quality makes them great to winter over in Zone 8 and southward.
In cold climates, some gardeners plant spinach in a cold frame or cover plants with hay and leave them all winter; they’ll be first to produce a very early spring harvest.
Troubleshooting
Heat and long days will end your crop, so plant as mentioned above.
Pests of spinach include flea beetles, spider mites, and aphids, which feed on spinach leaves. Diseases that attack plants are downy mildew, a mildew that may appear during cool, moist weather, and white rust, a disease that causes white spots on the leaves.
Harvest and Storage
Spinach leaves are ready to harvest as soon as they are big enough to eat. You can harvest two ways: 1) by pulling the entire plant, or 2) by removing only the outer leaves and allowing the center leaves to grow larger. The second way is better if you want the plants to keep producing. Picking the outer leaves also gives the advantage of briefly delaying bolting. In spring, when plants are about to bolt, pull them all up at once to enjoy them before they become bitter.