A Simple Guide How To Grow Spinach From Seeds

Spinach seed by Carmen Edenhofer
Image by Carmen Edenhofer

Spinach is a cool season plant that should have a space in every garden. This vegetable is easy to cultivate from seed and produces a harvest even Popeye would be proud of.

To grow spinach from seed, prepare the soil by adding plenty of compost and manure to satisfy this heavy feeder. Plant spinach in early spring as it will easily bolt in the summer heat. Sow the seeds in a shallow trench about 2.5cm (1inch) deep, with 8cm to 10cm (3-4inches) between them. With this spacing, you should not have to thin the seedlings. Keep your spinach patch weed-free, and water as necessary. You can begin harvesting at any point. Pick the leaves regularly and the plant will continue to produce more.

While you can grow spinach from the root of a harvested plant, the easiest and best way is to grow spinach from seeds. Follow these steps to grow amazing spinach in your garden.

  1. Think cool
  2. Soil preparation
  3. Sowing and germination
  4. Cultivation and harvest

1. Think Cool

Spinach is a cold-season vegetable. It thrives in cool weather, but quickly withers or bolts in the heat. Even the young plants are very cold hardy, and spinach plants have been known to survive down to -6°C (21°F). As such, it can be one of the first seeds planted in the spring, and it can be started even earlier in a cold frame and transplanted into the garden. It can also be planted in the late summer and, with a bit of cover, will be ready to harvest in the late fall. We had a few plants that self-seeded themselves in the fall, and the young seedlings survived winter chills of -40°C (-40°F) under a blanket of snow and grew beautifully again in the spring.

Many places that have temperate summers and mild winters where spinach can be planted and grown all year round.

Spinach leaves by Carmen Edenhofer
Image by Carmen Edenhofer

This hardy green, however, will quickly bolt in the long, hot days of summer. Bolting is when a plant becomes stressed, and puts all of its energy into producing seeds for self-preservation. Spinach bolts very quickly (sometimes all it takes is a few days), and very easily. The main reasons a spinach plant will bolt are too little water, temperatures over 23°C (75°F), and too much sun (when the days get longer than 14hrs). Warm weather will also greatly diminish the germination rate of spinach seeds, so it is best not to sow over summer.

If you do want to grow spinach during the summer, it is best to choose a bolt-resistant variety. Also, you can consider growing New Zealand Spinach. This plant isn’t actually a type of spinach, but it loves the heat and tastes very similar.

2. Soil Preparation

Spinach is a heavy feeder, meaning that it consumes a lot of nutrients from the soil as it grows. So when you are preparing your seedbed, don’t forget the compost and manure. Work a good amount of compost or well-rotted manure into the soil, and rake it into a smooth seedbed. The roots of a spinach plant do not grow very deep, so working the soil to a depth of around 10cm to 15cm (4-6inches) is sufficient.

Spinach will benefit from a wide array of supplements, and nitrogen can be particularly beneficial. Growing peas and beans with your spinach can be beneficial as legumes will add nitrogen from the atmosphere into the soil, making it available to the growing spinach.

Spinach prefers a soil pH of 6.0 to 6.5, so it might be worth doing a quick acidity test on your soil and adjusting as necessary. Again, compost comes to your aid by helping maintain this balanced soil acidity.

Spinach by Carmen Edenhofer
Image by Carmen Edenhofer

3. Sowing And Germination

Once your garden soil is prepared, it is time to plant your seeds. Spinach seeds will germinate well with a soil temperature ranging from 1°C to 23°C (33-73F), so you can plant your seeds directly into the garden very early in the spring. This is generally around 4 to 6 weeks before your last frost date.

Mark out your rows and use your weeder to make a shallow trench along the row. We like making our rows 30cm to 45cm (12-18inches) apart to give us enough space to walk between the rows and the mature plants have enough space to breathe. Plant the spinach seeds in the trench about 2.5cm (1inch) deep, then lightly cover the seeds by filling in the trench.

Most seed companies suggest planting the seeds very close together to compensate for unsuccessful germination and then thinning the seedlings. We prefer to space the seeds about 8cm to 10cm (3-4inches) apart to begin with. We find the germination rate to be generally quite high, and any seeds that do fail to grow will just give their neighboring plants a little extra space.

Many gardeners soak their spinach seeds before planting to accelerate germination. We have never done this and have good results, but you might want to give it a try to see if it works for you.

4. Cultivation And Harvest

All plants need water, and our spinach has almost always grown very well without watering them. There were a few notable exceptions when droughts were bad and we did end up watering our garden. On the whole, however, our spinach has always done well with the amount of water that nature saw fit. Remember, every garden is as different as the gardener, so watch your plants and make sure they don’t die of thirst. You can also mulch your spinach with straw or another organic matter. The mulch will not only retain moisture, but it will help regulate the soil temperature and keep the plants cooler in the hot weather.

Mulch will also keep the weeds down. It is important to keep your spinach rows free of weeds. This is especially true when the seedlings are small as the delicate shoots will easily be choked out. Once the plant establishes itself, it has a much better chance of competing with weed pressure, but your harvest will be much better (and your garden will look nicer) if you can keep the weeds at bay.

Thankfully, spinach reaches maturity very quickly, so you don’t have to weed for very long. Most varieties of spinach are mature in around 40 days, though some varieties are ready in less than 40 days.

Spinach and lettuce harvest by Carmen Edenhofer
Image by Carmen Edenhofer

Spinach leaves can be harvested at any point. When the plant is growing, several leaves will grow from the crown of the plant just above the ground. Pick these leaves as needed or cut the whole plant off 2.5cm to 5cm (1-2inches) above the ground and it will keep producing. If your plants produce faster than you can eat, they will develop a tall, thick stalk with dozens of leaves growing off it. Again, just keep picking the leaves and your spinach plant will keep producing them. At some point, when the plant either gets too mature or the summer heat is causing it to bolt, it might be worthwhile to pull of the whole plant, and harvest all the leaves for preserving.

Because spinach is often only grown in the spring, it is important to preserve some of the harvest for the rest of the year. Spinach can be dehydrated and stored in jars, or it can be blanched and frozen. When I was a kid, we would occasionally eat frozen spinach from the grocery store because it was “healthy.” My memories of this frozen spinach are of a bitter green mash that tasted almost as bad as the cardboard packaging it came in. Homegrown spinach that you blanch and freeze yourself is flavourful, delicious, and can be used in a variety of dishes.

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About the Author Harry Thompson

Involved in home renovations throughout his life, Harry is an expert in everything to do with home and garden DIY. In his spare time, he enjoys cooking and tending to his garden.