Updated: Sep 15, 2022
This dark leafy green originated from Persia and is a staple in salads and sandwiches. Spinach can be eaten both raw and cooked, and boasts a ton of nutritional benefits like high levels of vitamin C. When raw, it tastes sweeter and milder. After it’s cooked, spinach gets a more acidic and robust flavor.
To help ensure your Spinach thrives, we’ve put together this how-to video and transcript covering topics like:
Varieties of Spinach available
Caring for Spinach at all stages
Fertilizer and/or Mulching
Transplanting best practices
Spinach Companion Plants
Pests, Diseases and what to do about them
Harvesting and storing your Spinach
Listen to this Article:
Glossary of spinach terms
Before we get started, let’s learn a little bit about spinach.
The premature production of a flowering stem (or stems) before a crop is harvested. It’s the plant’s natural attempt to produce seeds for reproduction. Spinach is quick to turn bitter and go to seed (bolt) as the weather warms and the days lengthen, while drought can also accelerate the bolting process.
The first leaves that look like those of a mature spinach plant - not the very first leaves to appear. These true leaves have sharper edges and are thicker than the seedling leaves.
Water that’s been steeped with compost, which leaches some of its nutrients into the liquid.
Varieties of spinach
There are two types of regular spinach – smooth leaf and savoy leaf. The savoy types have more texture, but soil and sand tend to catch in the crinkles of their leaves.
Bloomsdale Long Standing A thick, crinkly variety with glossy dark green leaves. It typically takes 48 days to mature.
Winter Bloomsdale This variety is slow to bolt, tolerant to cucumber mosaic virus, cold tolerant, and good for over- wintering. It’s harvest-ready in about 45 days.
Olympia A slow-bolting variety best for a spring or summer harvest, it matures in 46 days.
Giant Nobel This long-standing variety has large, smooth leaves and matures in 43 days.
Indian Summer Resistant to some downy mildew and tolerant to spinach blight, this variety takes 39 days to mature.
Melody A lightly crinkled variety that’s resistant to downy mildew and is good as a spring or fall crop. It takes 42 days to reach maturity. Type A dark green, heavily savoyed variety that’s tolerant to downy mildew. It takes 39 days to mature. Vienna A medium to long-standing variety that’s heavily savoyed, it’s also tolerant to downy mildew as well as spinach blight. Vienna spinach matures in 40 days.
Starting your spinach seeds
Spinach is mainly started by seeds, and direct sowing is typically the best option.
Before you start, soak your spinach seeds in water overnight – this will soften the seed coats and speed up germination.
Once they’re ready, sow your seeds a half-inch (0.75cm) deep, spaced 1 inch (2.5cm) apart in rows that are 12- 18 inches (30-45cm) apart. Seeds can also be scattered across a wider area.
Their optimal soil temperature is between 5-20°C (45-70°F) with a day length of about 12 hours. Typically, seeds will germinate within 5-9 days.
You’ll also want to use a floating row cover to protect your seedlings from cold weather and insects.
Once the weather has warmed, remove the row cover or replace it with a more lightweight one. That way, your plants won’t be exposed to too much heat, and a lightweight cover will continue to protect your plants from flea beetles and leaf miners.
Spinach seeds don’t store well, so you’ll want to buy fresh seeds every year.
Caring for spinach
In this section, we’ll cover everything you need to know about soil conditions, thinning, watering and weeding, plus how to fertilize and mulch your spinach.
We’ll also talk companion planting as well as your growing structure options.
Spinach thrives in well-drained, fertile soil that’s high in organic matter. Their soil also needs lots of consistent moisture.
Typically, spinach tolerates slightly alkaline soils but it can be sensitive to acid soils – so ideally, its soil pH should be at least 6.0, but preferably in the 6.5 -7.5 range.
Overcrowding your plants stunts their growth and encourages plants to bolt. To avoid crowding, thin your seedlings to 4-6 inches (10-15cm) apart once they have at least two true leaves.
Spinach is a quick-growing, shallow-rooted crop that isn’t tolerant of water stress.
You’ll want to maintain enough moisture by frequently watering when needed – just be sure to avoid watering practices that splash soil onto the leaves or otherwise damages them.
Frequent, shallow cultivation with a hoe (or another tool) will kill any weeds before they become a problem.
Just be careful not to damage your plants when cultivating.
Mature spinach plants can tolerate temperatures as cold as 20°F (-6°C), but it’s best to protect them from freezing weather by covering their bed with a portable plastic tunnel or row cover.
Spinach will bolt in temperatures that are greater than 75°F (24°C), so if the weather warms up, try protecting your spinach under shade cloth set over a frame.
FERTILIZING AND/OR MULCHING
Spinach is a heavy feeder, and needs rich soil in order to thrive. Dig in a quarter to a half cup of a complete organic fertilizer beneath every 3 feet (1m) of row.
Fertilize with compost tea, fish emulsion, or cottonseed meal once your plants have about four true leaves.
Add herbicide-free grass clippings, weed-free straw, or other organic material to a depth of 3-4 inches.
This mulch layer can help prevent weed growth, which reduces the need for frequent cultivation.
TRANSPLANTING BEST PRACTICES
Since spinach seedlings have a tap root system, we don’t recommend transplanting. Seedlings might be susceptible to root damage, so it’s best to directly sow this crop.
You can fertilize spinach using compost tea, fish emulsion, or cottonseed meal once your plants have 4 true leaves.
GROWING STRUCTURE OPTIONS
A great option to use, just make sure they’re raised at least 6-8 inches above your existing soil.
Mix a minimum of 2-4 inches of compost into the row before planting. Spinach plants form a deep taproot, so for best growth, loosen the soil at least 1 foot deep before you plant.
Another great option - just keep in mind you’ll want to allow one plant for each 8-inch pot. In large containers, plant your spinach on 10-inch centers.
Since spinach is heat sensitive, you’ll also want to move your containers into the shade on hot days.
If you plan to use this option Baby’s Leaf Hybrid and Melody varieties grow especially well in containers.
COMPANION PLANTS DO’S AND DON’TS
You can grow your spinach with other greens, as well as in the shadows of tall crops like corn or pole beans.
Spinach is a particularly good companion for Brassicas, eggplants, leeks, lettuce, peas, radish, and strawberries.
Don’t plant your spinach near potatoes.
Common challenges and their solutions
There are a number of pests and diseases that can potentially harm your spinach. Not to worry – we’ve outlined them below, as well as how to either avoid or fix the problem.
Pests that create irregular, round-shaped tunnels (mines). At first, these tunnels/mines are long and narrow, but eventually they become an irregularly-shaped patch.
Solution: Radishes attract leaf miners away from spinach, so you can plant them together.
Also, natural enemies like parasitic wasps are known to reduce the number of leaf miners. Finally, there are some biological and cultural controls and sprays that can be used – like AZA-Direct and Neemix.
These pests are usually a problem for the undersides of leaves and/or stems of your plant. They tend to feed in groups on the undersides of branches – and often spread diseases.
Solution: Use a strong jet of water to wash them off your plants. Neem oil, insecticidal soaps, and horticultural oils are also effective against aphids. Just be sure to follow the application instructions on the packaging.
Oftentimes, you can also get rid of aphids by wiping or spraying the leaves with a mild solution of water and a few drops of dish soap (one variation includes adding a pinch of cayenne pepper).
Soapy water should be reapplied every 2-3 days for about 2 weeks.
Heavy feeding by these young larvae leads to skeletonized leaves.
Solution: Release their natural enemies to manage armyworm infestations. There’s also certain types of bacteria you can use to control these pests.
Caterpillars that leave large or small holes in the leaves. The damage they cause to your plants is often quite severe.
Solution: Looper numbers are usually held in check by natural enemies.
If they do become problematic, larvae can be hand-picked from your plants. You can also apply certain approved bacteria, which effectively kills the younger larvae.
SPINACH CROWN MITE
These pests are tiny and transparent, living deep in the crown of your spinach plant. They cause leaves to become deformed, and leave small holes in newly expanding leaves. They’re a problem both for young seedlings and for older plants.
Solution: You can try using hot pepper wax or insecticidal soap to get rid of these pests. Also, be sure to destroy crop debris immediately after harvest.
These pests leave large holes in the leaves, or they eat them entirely. They leave behind a slime trail, feed at night, and thrive in damp weather.
Solution: If possible, hand-pick any slugs at night when they’re most active. You can also try attracting them to traps either using cornmeal or beer.
For a beer trap, dig a hole in the ground and place a large cup or bowl into the hole. It’s best to use something with steep sides so that the slugs can’t crawl back out when they’re done.
Fill the bowl about three quarters of the way full with beer, and let it sit overnight. In the morning, the bowl should then be full of drowned slugs that can be dumped out for the birds to eat.
For a cornmeal trap, put1-2 tablespoons of cornmeal in a jar then lay the jar on its side near your plants. Slugs are attracted to the scent, but they can’t digest cornmeal so it eventually kills them.
You can also try placing a barrier around your plants of diatomaceous earth (a natural powder made up of the skeletons of tiny aquatic creatures) or even coffee grounds, since they can’t crawl over these.
Small water-soaked spots will appear on your plant’s leaves, which enlarge and turn tan or brown in color with a papery texture. This disease thrives in extremely wet weather, and its spores are usually spread by splashing water.
Solution: Plant disease-resistant seeds when possible. Also, avoid using sprinklers or overhead irrigation, and water your plants from their base to keep leaves as dry as possible.
DAMPING-OFF & ROOT ROT
These diseases cause the poor germination rate of seeds and the death of newly emerged seedlings. Older plants will also wilt and collapse.
Solution: Plant your spinach in well-draining soils, while carefully managing their watering to avoid soaking the soil.
When possible, use seeds that have been treated with fungicide, and avoid planting spinach successively in the same spot.
At first, yellow spots will appear on the leaves which then enlarge over time – turning a tan color with a dry texture. Purple fungal growth is usually found on the undersides of leaves, and severe infestations can cause curled and distorted leaves.
Solution: Plant disease-resistant varieties when possible.
Yellow spots will appear on the upper sides of leaves while clusters of white, blister-like pustules (pimple-like growths) appear on their undersides. Infected plants can collapse if the disease spreads fast enough.
Solution: There are some spinach varieties that are more tolerant of this disease, so try to plant them when possible.
Also, cultural control methods (like crop rotation, ample spacing, and sanitation of your tools) should also be used.
Harvesting and Storing
Within 6-8 weeks, you can start harvesting from any plant with leaves that are at least six 3-4 inches long. If you want your plants to keep producing, harvest by pinching off the outer leaves once they’re big enough to use.
You’ll want to avoid harvesting more than 50% of the leaves from a single plant. But, if you want to harvest the entire plant, simply cut it at its base and remove the older leaves.
For regrowth, leave about an inch below the leaves before clipping off the stems.
Store your spinach in its ideal conditions – a temperature around 32°F, with 95-100% relative humidity.
Spinach is very perishable, so it can only be stored for about 10-14 days.
Storage temperature should be as close to 32°F as possible, since your spinach will deteriorate faster at higher temperatures.