Spinach originated in Persia and the Levant where it was eaten for hundreds of years before taking the world by storm through global trade. In the modern world it’s hard to imagine spinach being an uncommon regional food. In more recent times, spinach is found rounding out saag paneer in India, filling enchiladas in Mexico, and giving super-strength to cartoon characters in Sweethaven.
The ubiquity of spinach is well-deserved. The leaves are rich in iron, potassium, fiber, and antioxidants. As a food crop it can be cooked with lemon and butter as a side dish, stuffed into dough and baked for Syrian spinach pies or eaten raw with nuts and fruit in a salad. If you're getting a little tired of homegrown kale and looking to expand your leafy green repertoire, read on to learn a few important principles for a successful spinach crop.
Germination In my experience the most challenging part of growing spinach is getting the seeds to sprout. Spinach is notoriously picky about when it will emerge from its seed and if they are sown directly into your garden beds they are also an attractive little snack for insects and birds. The best method that I have found to ensure good germination for spinach is to start the seeds inside in plug trays with moist potting soil and then transplant them into the garden when they have 2 or 3 true leaves. If you are having trouble getting the seeds to germinate in the potting soil, you can try sprouting them on a damp paper towel and then transferring them to the plug trays.
When to Plant Spinach is a cool weather crop and most varieties are very intolerant of excessively hot weather. If you live in a region with a cool, mild climate spinach will do well in most seasons. For those of us with hot summers and freezing winters, the best time to plant spinach is in the early spring and fall. Spinach can survive in your garden all winter under row cover, but as soon as the warm days and nights of summer come around the spinach will shoot up a flower stalk and try to produce seeds. This is referred to as “bolting.”
Bolt Tolerance Bolting in spinach is triggered by two factors: day length and temperature. Some varieties like Bloomsdale Longstanding, Emu, and Ashley are marketed as “bolt-resistant” or “heat tolerant.” These varieties will outlast other types of spinach, but eventually they too will succumb to the summer. Theoretically you could shade your spinach by growing it under other plants, thereby keeping it cooler and reducing its daylight hours, which could trick it into not bolting. But I haven’t tested this hypothesis.
Pests The most common insect pests for spinach are leaf miners and flea beetles. Leaf miners lay their eggs on the underside of the leaves and when they hatch the larvae tunnel through the cell walls of the spinach leaves causing extensive damage. Flea beetles leave small white dots on the spinach leaves; their damage is mostly cosmetic. Both of these insect pests can be mitigated by covering your garden beds in row cover before you plant your spinach and maintaining beneficial insect habitat so predatory insects can keep their populations in check. If you do find leaf miner damage in your spinach, the best form of control is to remove the affected leaves and take them far away from your garden. Because the leaf miner larvae are protected inside the leaves, pesticides are ineffective against them.
Mammals like groundhogs and rabbits can chew a spinach patch to the ground in a matter of minutes. If your garden is not already protected by a fence, a small barrier around your spinach patch is borderline necessary. You can construct these easily using chicken wire, zip ties and a few wooden stakes.
How to Harvest If you want to harvest full size leaves, spinach takes about 40 to 50 days from seeding to reach maturity. You can also pick the leaves as baby spinach at basically any point along the way. Spinach is a cut-and-come-again crop so as long as you only harvest the largest leaves on the outside of the rosette, the plant will keep pushing out new leaves until it bolts. Because spinach is so tender, it tends to wilt if picked during the warmer parts of the day. If the weather is warm, harvest your spinach in the early morning to increase its shelf life. If kept free of excessive moisture it can last in the refrigerator for up to 2 weeks.
In North America, thousands of miles away from where it originated, spinach tends to be a little bit finicky and can sometimes be a source of frustration for vegetable gardeners. Although if you follow the principles outlined above, you should have no problem growing a crop of spinach that Popeye would drool over.