What you're learning
- Is spinach easy to grow?
- When to plant spinach
- How long does it take to grow spinach?
- Where do you plant spinach in sun or shade?
- Spacing for sowing spinach
- Best soil type for growing spinach
- Planting spinach and how to sow seeds
- Sowing seeds indoors for planting out later in the season
- Common problems with seedlings
- Types of spinach
- Resistant varieties of spinach
- Grow spinach in containers
- How to care for your spinach plants
- Should I use fertilizer on my spinach plants?
- How to deal with pests and diseases
- Harvesting spinach with the cut and come again method
- Harvesting mature spinach leaves
- Companion planting with spinach
- Overwintering spinach
Spinach is a highly nutritious, high-yielding leafy green vegetable that is related to Swiss chard and beets. It grows very quickly and the leaves can be used both raw and cooked in a great variety of recipes. It’s a great addition to any veggie patch, and it can also be grown successfully in containers.
If you remember Popeye the Sailor Man and the source of his great strength – canned spinach – you’ll know that spinach has long been celebrated as a nutritional superstar. It’s a rich source of iron, vitamin A, vitamin C, vitamin K, folate, and calcium, as well as fiber.
Eating fresh spinach that you’ve grown in your own garden is a unique experience, and it’s also great for your health.
Growing spinach yourself is easier than you think!
Is spinach easy to grow?
If you meet the main growing requirements, then yes, spinach is very easy to grow! These main requirements to grow spinach, in brief, are:
- Sow spinach seeds in the cool weather of spring and fall
- Keep the soil moist – spinach is a thirsty plant!
- Harvest spinach leaves regularly to keep the plants producing new leaves
When to plant spinach
Spinach is a hardy, cool-weather plant, unbothered by temperatures as low as 14 F. Very warm weather and long daylight hours will cause spinach plants to bolt (flower) prematurely, so it’s best to sow seeds in the mild and cool weather of early spring and fall.
There are two seasons of salad spinach – in the Northern hemisphere, spring (April to early June) and fall (September to November). This means that spinach plants tend to stop producing new leaves in late summer when they focus on flowering and then start to die off. Similarly, spinach plants will stop producing new leaves in winter.
How long does it take to grow spinach?
Time from the sowing of seeds to harvest can be as little as six weeks, so it’s a great crop to sow in temporary empty spaces in your veggie garden.
To ensure you have a crop of spinach leaves throughout the whole season, sow your spinach seeds every two weeks in spring and fall.
Where do you plant spinach in sun or shade?
Spinach prefers partial shade in the summer and full sun in fall and winter. It’s one of the crops that can thrive in shady areas, which is useful if you have shady spots in your garden that are unsuitable for sun-loving plants.
Spacing for sowing spinach
You can plant 20-45 plants per 10 ft row, sowing seeds 3 inches to 6 inches apart, and with each row 18 inches apart. As the plants grow, you can thin them out by removing them completely or cutting them at soil level to avoid disturbing the roots of the remaining plants.
Small plants that have been thinned out can be used for baby salad leaves or in a stir fry.
If you plan on harvesting tender baby leaves for salads, you can sow your spinach seeds 3-6 inches apart, as regular harvesting will ensure that they won’t grow big enough to overlap and cause problems.
Plants left to grow to their full size should be spaced at least 12 inches apart, in rows 18 inches apart to allow for each plant to get enough light and airflow to stay healthy.
Best soil type for growing spinach
Fertile, well-drained soil with a pH of 6.5 to 7 is the ideal soil for growing spinach. Soil pH is important because it affects the nutrients available in the soil, and each type of plant has slightly different nutritional requirements.
You can test the pH of your garden soil and add substances to raise or lower the pH level. For example, adding pulverized lime will raise the pH of the soil, making it less acidic, and aluminum sulfate can be used on the soil to make it more acidic.
Prepare the soil for your plants by covering the ground you intend to plant spinach in with some well-rotted organic matter or compost in the early spring, a few weeks before the last predicted frost.
Planting spinach and how to sow seeds
You can sow the seeds directly into your garden as soon as the risk of frost is over. A soil temperature of less than 70 F is ideal because spinach is a cool-weather vegetable and hot weather will make it flower prematurely.
Water the soil thoroughly before you sow your seeds. Watering before sowing reduces the risk of washing the seeds away from their intended positions, which is more likely to happen when watering after sowing.
Use a dibber to make holes about 1 inch deep in the soil and space the holes as explained in the section above. Plant spinach seeds in every hole – you can place two per hole just in case one seed doesn’t germinate, and thin them out later if all are successful.
Cover the holes lightly with soil and mark where you sowed your seeds with the variety and date.
Sowing seeds indoors for planting out later in the season
Sowing and growing spinach seedlings indoors can work, but direct sowing into the garden or a container tends to be more successful at producing plants that are less likely to bolt as their roots are less disturbed.
You can get a headstart on growing spinach by sowing seeds in seed trays or modules indoors. This allows you to sow spinach as early as mid-February.
To work out the earliest date recommended for sowing spinach indoors, calculate the date six to eight weeks before the last expected frost in your climate zone.
There’s no way of predicting the weather, of course, but in general, the last frost date gives you a date to plan your seed sowing and planting around.
Common problems with seedlings
A common problem with growing seedlings indoors is uneven growth due to a lack of 360 degree light. Seedlings become ‘leggy’, or tall and spindly with long stems that grow towards the source of light.
The seedlings will waste energy on growing long stems instead of producing leaves, and very leggy seedlings can be hard to correct if they are already disproportionate.
You can try transplanting them into larger containers and bury the stem up to the leaves, or moving them to better lighting and hoping they don’t grow abnormally any further.
A greenhouse is ideal for optimum access to light, but you can also prevent this problem by using a grow lamp positioned directly above the seedlings, or rotating your seedling tray every day to maximize even light distribution over time.
Damping off is another issue that can stunt the growth of your seedlings or even kill them. This is when the seedlings are starved of oxygen because the roots are waterlogged from over-watering or dense soil.
Sowing seeds in well-drained soil and watering adequately (and not too much) reduces the risk of damping off.
Types of spinach
The spinach plant, or Spinacia oleracea, is an annual plant (i.e. a plant that lives only for one growing season) native to central and western Asia.
It’s thought to have originated in Persia – modern-day Iran and surrounding areas – and spread throughout the world through trade as it gained popularity as a vegetable.
Most of the USA is most familiar with flat-leaf spinach, with its smooth, spade-shaped leaves, but there’s also a type called savoy spinach which has dark green, crumpled leaves.
In addition to these two types, there’s semi-savoy spinach which has slightly crinkly leaves and the same texture and bitter flavor as savoy spinach.
Savoy spinach and semi-savoy spinach are best suited to cooking instead of being eaten raw due to their crisp texture and slightly bitter flavor.
Growing savoy spinach is the same as growing flat-leaf spinach, although you will likely want to harvest it at its full size instead of harvesting baby leaves for salads.
Resistant varieties of spinach
There are several resistant varieties of spinach that increase the chances of a productive crop.
Perpetual spinach is a vigorous variety that is especially hardy and resistant to cold, and it can be overwintered for first leaves in early spring.
What are F1 varieties?
You will notice on many seed packets the descriptor ‘F1’ referring to a variety of plants. This means it is a first-generation hybrid seed created by careful cross-breeding for desirable traits, such as resistance to disease.
One downside to F1 variety seeds is that the seeds produced from the plant grown will not have the same genetic material as the parent plant, and therefore seed-saving is not possible.
F1 spinach varieties that are resistant to downy mildew and bolting:
- Bordeaux – darker green leaves with beautiful red stems and veins
There are also spinach-like varieties of plants that are more resistant to warm weather and will produce leaves consistently even until late summer.
- New Zealand Spinach – although not a ‘true’ spinach, this leafy green vegetable is a great spinach substitute with a mild flavor. It thrives in the summer, so it can produce leaves during the midsummer gap when other spinach varieties stop producing.
- Malabar spinach – also not actually spinach, but the leaves are similar in appearance, and they are succulent with a mild taste.
Grow spinach in containers
A lack of space isn’t a problem if you’re deciding whether to grow spinach or not. Spinach grows quite happily in containers like pots and window boxes, provided there’s enough space between plants and the container is deep enough.
You might need to water your spinach more often if you’re growing it in containers, as the soil may dry out more quickly than garden soil that has access to groundwater.
In a container with a 15-inch diameter, you can have 7-15 plants.
How to care for your spinach plants
Once your seeds have germinated, it’s important to care for the seedlings consistently so they have the best chance at growing into healthy plants that will produce many leaves.
Spinach is a cool weather plant and requires regular, thorough watering. In very warm weather your spinach might even require daily watering so that its growth isn’t interrupted.
Plant spinach out in your garden as soon as the soil is ready and the risk of frost has passed.
Weeding regularly will remove plants that compete with your spinach for water and space, and remove hiding places for pests.
Weed between individual plants by hand to avoid damaging the leaves, and use a hoe to weed between rows.
Should I use fertilizer on my spinach plants?
If your compost is made from fertile organic matter, you probably don’t need to fertilize your spinach plants.
However, using a fertilizer can delay bolting early in the season, so it might be worth investing in a fertilizer that is rich in nitrogen.
Nitrogen is essential for healthy plant growth as it supports vigorous leaf growth and the production of chlorophyll, the green pigment in plants that enables them to make their own food.
You can choose between a top-dressing of a granular or pellet form of fertilizer such as poultry manure, or a liquid feed that you can dilute in water.
How to deal with pests and diseases
A disease that affects spinach is downy mildew, caused by fungus-like organisms that cause discoloration of the upper leaf surfaces and grey, white or purple mold on the underside of the leaves.
This disease renders the leaves inedible, and it spreads easily via airborne spores. Humidity and wet leaves increase the risk of downy mildew, and so good ventilation and watering plants from below at the roots will help to minimize it.
Managing damage by snails and slugs
Snails and slugs are especially fond of tender baby leaves and can damage them in a remarkably short amount of time.
Organic slug pellets will repel the critters without harming other garden life, and beer traps can be effective if you monitor them very closely and empty them frequently.
The best action can be prevention. Healthy plants are less likely to suffer from extensive slug and snail damage, so aim to keep your plants well-watered and remove any dead or dying foliage.
Check the immediate area for slug and snails whenever you can, and maintain the spacing between your plants so they have fewer places to hide.
Net plants to deter birds
Unfortunately, birds may take a liking to the tender young leaves, and they can quickly strip a leaf down to the stem. In the cool season when the ground is mostly bare, tasty green leaves stand out more starkly and birds will be able to identify them as a snack.
Netting your spinach rows will protect them from hungry birds.
Harvesting spinach with the cut and come again method
Will spinach grow back after cutting? Yes, if you cut it correctly.
The ‘cut and come again’ method is where you cut away the outer leaves of your spinach plants, leaving the small inner leaves to grow bigger until you harvest them, too.
Spinach grows very fast, and at peak growing season you can harvest baby leaves every week for a few weeks. This method is best for cutting salad leaves that are small and tender, and you can let the leaves grow to the size you prefer.
Harvesting mature spinach leaves
If you prefer to grow spinach for larger leaves, allow your plants to grow for 10-12 weeks so they can reach maturity.
Use a sharp pair of clean scissors and cut all the leaves off about 1 inch from the base of the plant. A smaller crop of baby leaves should follow this initial harvest.
Companion planting with spinach
Grow spinach with brassicas like kale, cauliflower, and cabbage. Brassicas (also called cruciferous vegetables or the mustard family of plants) don’t compete with spinach for nutrients at all, which makes them great veggie patch companions.
You can also grow spinach with the following companion plants:
- Swiss chard
- Alliums, like chives, garlic, and onions. They deter pests that love eating spinach.
- Nightshades, like peppers, tomatoes, and eggplants
- Cucurbits, such as cucumber, melon, and zucchini
- Beans and peas – they fix nitrogen in nodes at their roots, which spinach can then access.
- Umbellifers like carrots, celery, parsley. Their strong aroma will deter spinach-loving pests.
Crops to avoid planting with spinach:
- Fennel. This plant consumes the same nutrients that spinach needs, and it produces compounds that stunt the growth of your plants.
- Potatoes – suck up nutrients that your spinach needs, and can disturb the soil and the delicate tap roots of your spinach.
It’s possible to grow spinach outside of the usual cool season of spring and fall if you want to overwinter your plants for early spring harvests. Overwintered plants will produce during the ‘hungry gap’ when not many other plants are growing.
Row covers will keep your spinach alive through a cold winter by insulating the plants from frost and extreme temperatures.
Spinach is an easy vegetable to grow at home, and with these tips, you’ll be off to harvest spinach from your very own garden in no time.