When it comes to vegetable gardening, mastering how to grow spinach can yield a continuous crop with higher nutritional benefits than most other edible plants.

Contrary to popular belief, iron isn’t even among the top five nutrients the green leafy vegetable provides — vitamin K and A lead the list — so strong muscles aren’t all there’s to gain.

The fast-growing cool-season plant taking its name from the Latin for spine is known to reduce cholesterol, the risk of heart disease and cancer, improve eyesight, brain and gastrointestinal function.

Spinach has the advantage of surviving hard frosts, which means it can be planted as soon as the ground thaws in early spring — when nothing else grows — and can be enjoyed over a longer period than many vegetables. Not to mention its quick maturity, 30 to 45 days.

Whether planted outside or started indoors, as recommended by the National Garden Bureau (NGB) to maintain cooler soil and temperatures, learning how to grow spinach requires careful planning.

Tools you’ll need:

Outside

  • Spinach seed
  • Tiller
  • Garden spades, trowels, shovels
  • Compost or dried manure
  • PH test kit
  • Lime or wood ash
  • Sulfur or peat moss
Indoors
  • Flats or pots of peat or plastic
  • Fluorescent-light garden
  • Germinating mix
  • Mister
Site selection and timing:
  1. Pick a site in full sun to slight shade, but not too much heat. Warm weather makes spinach bolt faster, or produce flowering stems and seeds. The soil can be as cool as 50 degrees.
  2. Plant spinach four to six weeks — average maturity time — before your last spring frost date and again before the first fall frost date. For indoor plants, start seeds about three weeks before you want to transplant.
Preparing the soil:
  1. Test the soil’s pH for acidity to ensure it has a neutral pH of about 6 to 7.5. If more acidic with a lower pH, add lime, or use sulfur for the opposite effect.
  2. Till the garden bed to loosen the soil to a depth of 6 to 8 inches.
  3. Mix in organic matter such as compost or dried mature, a 2- to 4-inch layer.
How to plant:

Outside

  1. Sow seeds ½ inch deep, about two inches apart, with 1 to 1 ½ feet between rows.
  2. Cover seeds with ¼ to ½ inch of soil or compost.
  3. Water well.
  4. For a continuous supply of spinach, plant every two to four weeks.
Indoors
  1. Sow seeds evenly about an inch apart in flats, or two to three seeds per pot.
  2. Cover with one-quarter inch of watered-down germinating mix.
  3. Settle the seeds by watering with a mister.
Recommended tools for maintenance:
  • Mulch
  • Nitrogen-rich fertilizer
  • Fish emulsion and cottonseed meal
  • Pruners
  • Row covers or fencing
Routine maintenance:

Outside

  1. When the plants are about 4 inches tall, thin to keep 6 to 8 inches apart. Pick outside leaves often to encourage new growth.
  2. Spread a nitrogen-rich fertilizer around the base of the plants or along the length of a row. Work into soil by digging or watering. If using fish emulsion, dilute first. Repeat whenever you thin the plants.
  3. Water every few days.
  4. Mulch to retain soil moisture.
  5. Use a fence or gardening net to divert garden pests.
Indoors:
  1. Once seeds emerge, in a week to 10 days, place containers on a windowsill in direct sun or in a fluorescent-light garden.
  2. Thin seedlings when they reach 2 inches in spread, leaving 2 to 3 inches between them in flats or one seedling per pot. Snip unwanted seedlings at soil level.
  3. In about a week, transplant the seedlings outdoors into the garden or containers. Set seedling at the same level they were growing in the flat. Space transplants 6 to 8 inches apart.
Harvest cycles:
  1. Sow a little every week to 10 days for two to four weeks.
  2. To harvest early, cut individual leaves as soon as they are big enough to eat.
  3. When the weather warms, cut the whole plant close to the ground, below the lowest leaf.
  4. Harvest again after a few new leaves reappear.
Tips:

Outside

  • Sow seeds among rows of peas to take advantage of the light shade pea vines provide.
  • Six to 12-inch window boxes or rectangular planters on a deck or steps subvert rabbits and other pests.
  • Tyee and Melody make good fall crops and are resistant to disease. Other fall suggestions are Avon, Indian Summer and Razzle Dazzle, and for winter, try Bloomsdale Long Standing and Cold Resistant Savoy.
  • While not the genuine article, Malabar spinach and New Zealand spinach are similar in taste to spinach and thrive in hot weather.
  • Smooth leaf varieties are easier to clean.
Indoors
  • To keep the soil moist, place the containers in plastic bags secured with twist ties.
  • Biodegradable peat pots go directly in the ground instead of having to be transplanted, and they maintain proper spacing between plants.
  • Transplant on an overcast, calm day.