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The best time to plant spinach plants is in the cool weather of early spring or late summer.
When you plant spinach plants at these times, you’re working with the vegetable’s natural love for cooler temperatures.
If you’ve been wondering when to plant spinach plants, the short answer is that you want to avoid the heat of summer.
Spinach plants will bolt, or go to seed, when temperatures rise above 75°F, which ruins the leaves.
In this post, we’ll cover when to plant spinach plants for a spring harvest, when to plant spinach plants for a fall crop, and the key factors that make the timing work.
Let’s dig into the best schedule for your spinach plants.
When to Plant Spinach Plants: Spring Timing
When to plant spinach plants in the spring depends entirely on your local frost dates.
You can plant spinach plants as soon as the soil can be worked in early spring, even if there’s still a chance of a light frost.
Spinach seeds germinate in soil temperatures as low as 35°F, which is why you can plant spinach plants so early.
The ideal soil temperature for germination is between 50°F and 65°F, so aim to plant spinach plants about 4 to 6 weeks before your last expected frost.
For most gardeners, that means planting spinach plants in March or early April, but you should always check your local frost dates first.
Spinach plants are remarkably cold-hardy, and mature plants can survive temperatures down to 20°F.
This is why you can plant spinach plants well before other vegetables like tomatoes or peppers.
The key is to get your spinach plants in the ground early enough that they mature before the heat arrives.
When you plant spinach plants in early spring, you can usually harvest your first leaves in about 40 to 50 days.
If you want a continuous harvest, you can plant spinach plants every two weeks until the weather warms up.
This succession planting ensures you always have fresh spinach plants coming along.
1. Soil Temperature Matters Most
When you plant spinach plants, the soil temperature is the most important factor to get right.
Spinach seeds will not germinate if the soil is too warm, above 75°F, so early planting is critical.
You can use a soil thermometer to check conditions, but a good rule of thumb is to plant spinach plants when the soil feels cool and damp.
If you plant spinach plants too late in spring, the seeds may fail to sprout or the plants will quickly bolt.
So always err on the side of planting spinach plants a little earlier rather than later.
2. Frost Tolerance Gives You a Head Start
The reason you can plant spinach plants so early is their excellent frost tolerance.
Unlike tender crops, spinach plants don’t mind a little chill in the air.
In fact, a light frost can even sweeten the leaves by converting starches into sugars.
So when you plant spinach plants in early spring, you don’t need to worry about protecting them from a light cold snap.
Just make sure the ground isn’t frozen solid when you plant spinach plants.
When to Plant Spinach Plants: Fall Timing
When to plant spinach plants for a fall harvest is equally important for getting a second crop.
You should plant spinach plants about 6 to 8 weeks before your first expected fall frost.
For most regions, this means planting spinach plants in late August or early September.
The reason you plant spinach plants this early in fall is that they need time to establish before the days get short and cold.
Fall-planted spinach plants will grow slowly as temperatures drop, which actually improves their flavor.
One of the best tricks is to plant spinach plants in fall for a harvest that can last well into winter.
If you plant spinach plants under a cold frame or row cover, you can keep picking leaves all winter long.
When you plant spinach plants in late summer, the soil is still warm from summer, so germination is quick.
But the trick is to keep the soil moist until the seeds sprout, since hot August sun can dry out the top layer fast.
You can also plant spinach plants in containers in fall, which makes it easier to move them to a sheltered spot if a hard freeze threatens.
1. Day Length Affects Bolting
When you plant spinach plants, you also need to think about day length.
Spinach is a long-day plant, meaning it bolts when days get longer than about 14 hours.
This is why you plant spinach plants in spring and fall, when days are shorter.
If you plant spinach plants in late spring when days are long, they’ll go to seed almost immediately.
So the timing of when you plant spinach plants is all about avoiding those long summer days.
2. Fall Spinach Plants Overwinter Easily
When you plant spinach plants in fall, you have the bonus option of overwintering them.
Mature spinach plants can survive the winter with some protection, and then they’ll grow again in early spring.
This means you can plant spinach plants in fall and get an early spring harvest before any new sowing.
If you live in a mild climate, you can plant spinach plants in fall and simply leave them in the ground.
In colder zones, you might plant spinach plants in fall and add a thick layer of mulch to protect the roots.
Key Factors That Influence When to Plant Spinach Plants
Beyond frost dates, there are a few other things that should guide when to plant spinach plants.
Your specific microclimate, the variety of spinach, and your local weather patterns all play a role.
Let’s look at these factors so you can refine when to plant spinach plants in your own garden.
1. Choose the Right Variety for Your Timing
When you plant spinach plants, the variety you choose can change the ideal timing.
Some varieties, like ‘Bloomsdale’ or ‘Winterbor’, are extra cold-hardy and are perfect when you plant spinach plants in fall.
Other varieties, like ‘Space’ or ‘Correnta’, bolt more slowly and are better when you plant spinach plants in early spring.
So when you plant spinach plants, always check the seed packet for days to maturity and bolting resistance.
2. Monitor Your Local Weather, Not Just the Calendar
The calendar is a great starting point when you plant spinach plants, but weather is the real boss.
If you get an unusually warm spring, you may need to plant spinach plants earlier than normal.
Conversely, if it’s a cool, rainy spring, you can push your planting date later.
The best approach is to plant spinach plants based on soil temperature readings rather than a fixed date.
Once the soil hits 50°F, that’s your green light to plant spinach plants.
3. Succession Planting Extends Your Harvest
If you’re unsure when to plant spinach plants, use succession planting to cover all your bases.
You can plant spinach plants every 10 to 14 days from early spring until late spring.
Then you can plant spinach plants again in late summer for fall.
This way, even if one batch of spinach plants bolts early, you’ll have another batch coming up.
Succession planting is especially smart when you plant spinach plants because it gives you a steady supply of tender leaves.
So, When to Plant Spinach Plants?
So, when to plant spinach plants comes down to two clear windows, early spring and late summer.
You should plant spinach plants in early spring, about 4 to 6 weeks before your last frost, as soon as the soil is workable.
You should also plant spinach plants in late summer, about 6 to 8 weeks before your first fall frost, for a delicious second crop.
So, when to plant spinach plants in your garden depends on your frost dates, but these guidelines work for most climates.
When you plant spinach plants at these times, you’ll avoid the heat that causes bolting and get the sweetest, most tender leaves.
So, when to plant spinach plants is not a complicated question, just remember cool weather and short days.
Hope this post has helped you figure out when to plant spinach plants for a bountiful harvest all season long.