How to Grow Spinach Indoors

Spinach is an ideal crop to grow indoors in containers. The spinach
plants stay small and continue to grow and produce numerous harvests.
Learn how to setup your containers and grow spinach indoors.

Spinach is a cool season crop that adapts well to indoor growing
conditions, including cooler winters, and air-conditioned summers. Given
its compact size, and love of cooler temperatures, spinach is a great
choice for indoor gardening. Learn how you can grow spinach indoors all

Growing Spinach Indoors

We have a glorious sunroom on the second level of our house. It faces southward and has big old windows all the way around.

In the summer time I grow a lot of our potted edible plants in this
sunroom. They love the bright light and lack of leaf eating insects.

In the winter this room gets plenty of light, but there is no
insulation, so it is mighty chilly. Most of our plants move downstairs
for the winter months.

In late autumn, I started wondering if I could grow cold weather
crops in the sunroom and have fresh produce in winter. I grabbed an old
window box from our shed and dumped some soil and compost inside. Tiny
little spinach seeds were carefully poked into the soil. I moved it into
the sunroom and waited.

Nothing happened.

The soil was a bit dry so I watered it and waited again. Still
nothing. Then a light bulb went off. Literally! I realized I needed to
warm the soil in order for the seeds to germinate. Our handy dandy heat
lamp came to the rescue! I clipped it to the box, turned it on and
waited once again. Victory!! After a few days, tiny little seedlings
were popping up out of the soil.

I took care of the little babies for weeks, they grew and they grew.
They were at baby spinach size in a few short weeks. Finally, they were
ready to harvest. So, it’s official, you really can grow spinach in a
window box!

Those of you who follow these posts know that we’ve had our fair share of garden failures so it’s nice to have something work out right once in a while.

Growing leafy green edibles indoors is very similar to growing
houseplants. All they need is good quality soil, water, and sunlight.

What You’ll Need to Grow Spinach Indoors:

  • Window Box: Any size window box will do. Aim for at least 6-8 inches deep. You will need one with a tray to catch extra water.
  • Organic Potting Mix: Enough to fill the window box. Don’t use soil from your garden. It may introduce disease to your young seedling.
  • Organic Fertilizer: A granular, slow release fertilizer that you mix into the soil before planting is best, or you can water with fish emulsion
    to fertilize. Fish emulsion does have an unpleasant odor to it, but if
    your window box is in an area away from you living space, it may not
  • Spinach Seeds: Varieties to consider include Renegade and Butterflay.
  • Heat Mat:
    Spinach seeds will germinate at a temperature between 40˚F to 75˚F, but
    will sprout quicker in warm soil. Use a heat mat until they sprout.
  • Sunny South Facing Window
  • Water as Needed: Fill a watering can and keep it handy to make watering easier.

How to Plant Spinach in a Container:

  1. Fill the window box with potting mix.
  2. If using slow release fertilizer, follow the directions for the
    amount to use for your container. Add and mix to combine with the
    potting mix.
  3. Pre-moisten the potting mix before sowing your seeds. Add warm water
    into the window box and let it drain. You will want the soil mix
    slightly damp, but not soaking wet.
  4. Sow your spinach seeds. Go ahead and sow your seeds heavily and
    plant them about 2 inches apart. Push them slightly into the soil about
    1/8-inch deep, cover, and mist with water.
  5. Place the window box on a heat mat.
  6. Check the window box every few days for germination, mist with water
    if the soil surface has dried out, and wait for seeds to emerge from
    the soil. Once the seeds sprout, remove the container from the heat mat
    and place in a sunny window.
  7. Water when the soil feels dry at the surface. You want to keep the soil moist but not waterlogged.
  8. Harvest baby spinach by snipping individual leaves from the outside
    of the plants. The center of the plant will continue to grow and produce
    more foliage.
  9. As the spinach plants get crowded, thin them to about 6 inches apart
    by cutting the entire plant right below its crown. This will give the
    remaining plants room to grow larger.

Spinach is finished growing when the plant bolts, or sends up a seed
stalk. Since spinach is a cool season crop, hot weather and increased
daylight naturally triggers spinach to bolt. Pull the plants, compost
them, and try growing something else.

I hope our experience will encourage you to try growing spinach indoors in containers.

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