Growing spinach indoors is something that anyone can do. Growing lettuce might be even easier, but spinach is also a very easy plant to grow. To do so successfully, you need to think about:
- Where you grow the spinach.
- What you grow the spinach in.
- Which type of spinach you grow.
- How to sow the seeds.
- And how to care for and harvest your crop.
Below, we will look at these items more closely to help you learn how to grow spinach indoors year-round.
Choosing Where to Grow Spinach Indoors
To find the best way to grow spinach indoors, you should first look at where you live. Homes can differ in how bright and warm they are and the growing conditions that they can provide. Choose the right location inside your home for your indoor vegetable garden.
Think about how much light enters your home, and how this changes throughout the year. Spinach will like a spot that is bright but cool. It fares better in a location out of direct sunlight.
True spinach ‘bolts’ in a location that is too bright and warm. It flowers and sets seeds too early – reducing the length of the harvesting period. Keep things cool so this is less likely to occur.
Over the autumn and winter months, spinach is less likely to bolt. However, in most temperate regions, especially further north, lack of light can be an issue over the coldest part of the year when growing indoors. Grow lights are often necessary.
Growing spinach indoors with grow lights can help prevent legginess and ensure healthy plants and a successful harvest.
Container Options for Indoors Spinach Cultivation
Learning how to grow spinach in a pot indoors filled with a general-purpose, peat-free potting mix is the obvious choice.
But when growing spinach indoors hydroponics or aquaponics is also an option. Hydroponics and aquaponics involve growing spinach in water rather than a soil-like medium. In aquaponics, fish are also reared within the system, fertilizing plants and potentially providing another food source.
True spinach and other types of spinach too can grow well in such systems. And these systems can be a sustainable choice since they can use less water and produce more food in less space than other comparable growing methods.
Types of Spinach To Grow
When we talk about how to grow spinach indoors, we are usually talking about true spinach – Spinacia oleracea. This spinach can bolt, though it is generally easy to grow. But it is an annual plant, that you will have to sow anew each year.
Other plants also have the name ‘spinach’. These might also be options for indoor growing. For example:
- Perpetual spinach – AKA chard – Beta vulgaris ssp. vulgaris
- Water spinach – AKA kangkong – Ipomoea aquatica
- Malabar spinach – AKA vine spinach – Basella alba
- New Zealand spinach – Tetragonia tetragonoides
- Tree spinach – Chenopodium giganteum
- Sissoo spinach – Alternanthera sessilis
- Longevity spinach – Gynura procumbens
- Okinawan spinach – Gynura bicolor
These resemble true spinach in use but are not closely related to it.
There are also many other leafy greens, many perennials (living over several years) that resemble spinach strongly in texture and flavor.
Even plants that cannot be grown outside in a temperate climate work well for indoor cultivation. Some of the plants on the list above are tropical, and so not suited for outdoors growing in cooler climes. But indoors you have the luxury of growing heat-loving, tender crops including a range of spinach-like crops.
These other plants, which can be eaten raw or cooked, also make great additions to an indoor garden. Often these perennials are easier to grow indoors than true spinach and provide more food over a longer period.
In the rest of this guide, we will focus on growing true spinach, Spinacia oleracea. Though perennial spinach substitutes are also all well worth considering for your indoor garden.
Sowing Spinach Seeds
Sow true spinach seeds little and often and you can potentially grow spinach and harvest spinach indoors all year round.
In temperatures between 15 and 20 degrees, true spinach seeds germinate and grow quickly. A crop of baby spinach leaves can be ready to harvest in as little as 4-6 weeks.
Simply sow the seeds in trays, pots, or other containers, filled with a peat-free seed-starting compost. Cover them lightly with a little more of the growing medium.
Sow batches every couple of weeks between March and May, and around in August and September and you can harvest every month of the year.
Select a suitable variety to sow in late summer or early fall – some varieties do better over winter than others, even indoors. In spring, for summer harvests, it can be helpful to choose a variety that is more bolt resistant.
Care & harvesting When Growing Spinach Indoors
Spinach needs to be kept well watered throughout the growing season and so you need to make sure that the growing medium does not dry out. Water early in the morning if possible.
Water at the base, not from above, and try not to splash water on the leaves as this can make fungal diseases more likely.
When growing spinach indoors, it is common to harvest while the leaves are still fairly small, as baby spinach leaves.
If you want to grow larger spinach leaves, you can harvest tiny baby spinach leaves as you thin out your spinach seedlings, as soon as they are large enough to handle. You can then take every second plant for salads a few weeks later, leaving more space for the rest to grow.
Harvest leaves as needed, rather than all at once. You will get 2-3 harvests from the plants before they go to flower, at which point the harvest will be over. The leaves of true spinach taste bitter once the flowering period begins.
If you have sown more seeds you can continue to enjoy batches of spinach leaves to use in salads or cooked recipes throughout the year.