Why Is Your Spinach Growing So Tall?

Spinach is versatile, nutritious, easy to maintain, and can add a vibrant pop of color to any garden – in short, it’s the perfect plant to grow. However, beginner and seasoned gardeners can still struggle to grow the perfect spinach plant, especially if they can’t provide optimal growing conditions. If this is your first time growing spinach, you might even feel worried about its sheer size, as the plant can quickly tower over your garden.

Your spinach is growing so tall because it’s natural for it to grow to 1 or 2 feet (30 cm to 61 cm) tall. If your spinach grows taller than this, issues like failure to harvest, poor growing conditions, and mutations can be to blame, all of which can lead to an inedible harvest.

There are many caveats to the explanation above, so let’s explore the topic of spinach growing too tall a little more in-depth. Below, I’ll answer whether a tall spinach plant is a good sign. I’ll also go over some of the most common reasons why the plant might be overgrowing, the best time to harvest spinach, and how the plant can be affected by bolting.

Is Tall Spinach a Good Thing?

Tall spinach is a good thing because it signifies that your plant is healthy and thriving in its environment. The only instance in which tall spinach isn’t a good thing is if you find it unsightly or if the spinach is excessively tall.

If you notice your spinach plant reaching 1 or 2 feet (30 cm to 61 cm) high right around the time of harvest, it’s a healthy sign. Most spinach species that reach this height are fully grown and ready to be eaten, meaning that the growth process has been successful and you have provided the plant with all the necessary growing conditions.

However, before determining whether excessive height is something to worry about, you first need to determine what “excessive height” entails in your particular case. That’s why, if you get your plants from your local nurseries, you want to save the informational label attached to them. That’ll give you a rough idea of how tall you can expect your spinach to grow. 

If you’ve accidentally lost that information, you can still reach out to local nurseries and inquire about the specific species of spinach you’re growing. If you don’t know much about the type of plant you’re growing, you can reliably stick to 1 or 2-foot-tall expectations.

Excessively tall spinach is typically only a bad thing when the plant has overgrown so rapidly that it has surpassed all your set height expectations. While, in this instance, gardeners might believe that they’ve done something right to have their plant exceed any size expectations, they’d be surprised to learn that overgrowth can be just as dangerous as undergrowth. 

Overgrowth results from a problem in the plant’s life cycle, and it can render your entire harvest inedible. It’s hard to pinpoint what the trigger of this issue might be without examining the plant itself, but generally speaking, potential problems include the following: 

  • Poor growing conditions
  • A mutation or hormonal dysfunction
  • Failure to harvest at the right time

Reasons Spinach Might Grow Too Tall

Let’s take a closer look at the potential causes for excessively tall spinach. How do they exactly affect spinach growth, and how do they usually present themselves? Keep reading to learn more.

Poor Growing Conditions

Upon reading “poor growing conditions” on this list, you might feel surprised. How can incorrect growing conditions make a plant surpass its expected size? Surprisingly enough, it’s a common phenomenon.

An excellent example of how this can happen is if your growing space doesn’t have enough light. Ideally, a spinach plant needs 4 to 6 hours of sun per day. When the plant doesn’t receive all the light it needs, it grows taller and leggier in search of a light source, ultimately surpassing the 1-to-2-foot benchmark. That’s why you should ensure that all the plant’s light, nutrient, water, and soil needs are met.

Failure To Harvest at the Right Time

This is usually the main cause of spinach overgrowth, and it, unfortunately, comes as a result of human error. Keep in mind that “human error” in this instance doesn’t always mean that you were negligent toward your plant. Sometimes, you can watch your spinach like a hawk and still miss important signs due to inexperience. 

Lack of knowledge or previous experiences can also make you uncertain, even if you do notice a sign or two. Not wanting to risk an early harvest, you wait, and you wait until it’s too late – a scenario every gardener can relate to.

Unfortunately, as I’ll also explain in one of the following sections, once the spinach starts bolting, the leaves become bitter or tasteless, meaning your hard work will have gone to waste.

That’s why it’s imperative to find the right time to harvest your spinach – neither too early nor too late. However, sometimes even the most careful gardeners miss the cues the plant sends when it’s ready for harvest. 

Mutation or Hormonal Dysfunction

This one’s the only potential reason that’s out of your control. Sometimes plants develop mutations or hormonal dysfunctions that are challenging to combat. What’s more, while some of these conditions are known and studied, others can be completely new, meaning the only choice you’ll be left with (supposing this is actually the case) is to get rid of the plant altogether and start again next season.

However, before taking such a drastic measure and throwing all of your hard work away, it’s worth consulting with a botanist or another professional that can help you better get to the root of the problem.

When To Harvest Spinach

Unfortunately, there’s no mathematical equation that can help you determine when your spinach is ready to harvest. With that said, there are still plenty of signs and methods you can rely on to make an educated guess.

Upon researching the topic, you’ll find that some sources are inconsistent in their suggestions. However, there’s an overall consensus that spinach is ready to harvest once its height surpasses its width and the outer leaves reach a length of about 6 inches (15.24 cm)

Remember that different spinach species have different-sized leaves, so always keep the informational pamphlet that came with your plant on hand to refer back to it whenever you need to.

Moreover, if you’re growing your spinach in spring and notice that the plant is about to bloom (or bolt), you’ll want to harvest it immediately. As I’ll explain below, spinach that has bolted has already gone to waste, so you should act as quickly as possible. 

Another technically correct but less precise suggestion is to harvest spinach leaves as soon as they’re large enough to eat. Though this approach might seem vague initially, if you’re an avid spinach eater, you already know what your harvest should look like without even needing to measure the leaves.

Before we move on to alternative suggestions, I want to mention that you should harvest spinach in layers. You remove the outer layer of leaves first, and this gives the smaller ones an opportunity to grow. 

As soon as they’re big enough, you can harvest the inner leaves too. I know that this process is more tedious and time-consuming than if you were to just harvest them all at once, but your effort will surely pay off in the final taste of your dishes.

Keep in mind that this suggestion doesn’t apply in those instances when the spinach is about to bolt. Once the blooming process has taken place, the plant will grow even taller, but its leaves will quickly turn tasteless or, even worse, bitter. 

So, if you find yourself in this situation, removing all the leaves or pulling the plant altogether is the best course of action. I also urge you to taste as you harvest to make sure the spinach you’ll be bringing home is pleasant-tasting. In some instances, the leaves might turn bitter faster than expected.

Bolting is a consequence of failing to harvest at the right time, and it can cause the plant to grow even taller. That’s why the phenomenon is commonly linked to overgrown spinach. Knowing that it’s time to learn a bit more about what bolting actually is, some of its tell-tale signs, and what you can do to prevent it from occurring and, in turn, your spinach from overgrowing.

How Does Bolting Affect Spinach Size?

Bolting (or going to seed) is a term used to refer to the phenomenon where a plant blooms prematurely, developing a flowering stalk right when it’s most inconvenient. It’s “inconvenient” because the plant starts redirecting a great deal and nutrients and energy to the new growth, leaving the rest of its structure underfed. 

With spinach, you want to harvest the leaves and not the flowers. This phenomenon can often negatively affect your harvest, which is why you’ll want to avoid it at all costs.

However, what does bolting have to do with an overgrown spinach plant? You’d be surprised to learn just how connected these two phenomena can be. When the plant blooms unexpectedly, a surge of nutrients and energy goes toward its growth as its organism tries to sustain the new flowers. That’s why when your spinach starts bolting, you’ll notice it growing way taller than usual. 

Bolting is an issue that most gardeners, especially amateur ones, have to deal with at one point or another. What casual growers might not know, for example, is that all garden vegetables can bolt if left unharvested for long enough, and spinach is no exception. So, while you wait that extra day or two to ensure your crops are fully ripe, remember that waiting too long might make all your harvest go to waste.

That said, there are some triggers that might cause a spinach plant (or any plant, for that matter) to bolt sooner or be more prone to the phenomenon altogether. For example, when the growing conditions aren’t ideal or the plant is stressed, it’s far more likely to bolt sooner than expected. 

It’s interesting to note that poor growing conditions can contribute both directly and indirectly to an overgrown spinach plant, which just goes to show how interconnected the factors that affect the well-being of a plant really are.

Now that you know what bolting is and why it’s important to prevent it from occurring, it’s time to learn about the signs to look out for before it’s too late. Once you notice one or more of the occurrences listed below, act quickly and harvest your spinach as soon as possible. 

Signs That Spinach Is About To Bolt

Here are the most common signs your spinach is about to bolt:

  • The plant is growing too tall. As mentioned previously, as soon as your spinach grows uncommonly tall, you should stay alert for the possibility of bolting. Generally, spinach grows horizontally rather than vertically, although when it’s ready to be harvested, it’ll be slightly taller than wider. However, when it starts growing uncontrollably and becomes more than 2 feet tall, there’s an issue.
  • The main stalk suddenly becomes thicker. A spinach stalk is typically fairly narrow, as the well-established nutrient transport system has plenty of space to reside within it. However, when the plant becomes ready to bloom, that surge of nutrients I mentioned earlier wouldn’t be supported by the narrow, delicate stalk. That’s why, right before the plant bolts, you’ll notice this part getting visibly thicker. 
  • The leaves change shapes. If you’ve grown spinach before, you know that its leaves are quite rounded around the edges, creating an oval shape. However, when the plant’s about to bolt, you’ll notice the leaves becoming more angular at their edges, creating an arrowhead shape. This change is a tell-tale sign of bolting.

If you’ve noticed one, or worse, several of these signs, it’s time to take action. If you ignore the warnings that the plant is giving you, you might end up with an inedible harvest. The best solution is to harvest the leaves immediately or pull the plant altogether. While you might lose some under-grown leaves in the process, it’s still better than being left with no harvest at all.

There are some approaches you can try to salvage your bolted spinach. However, those come with no guarantees. That’s why it’s best to move the harvesting date closer and save the leaves you can, always tasting as you go to make sure they’re not bitter or rubbery.

If your plant hasn’t shown any of these signs yet, you’re in luck! You can still take some steps to prevent or delay bolting as much as possible so that you can comfortably harvest your spinach on your own schedule. 

Here are some of the measures you can take:

  • Follow a strict watering schedule. Hydration levels play an essential role in the well-being of any plant, spinach included. While beginner gardeners may consider watering the easiest part of the process, it’s quite complex. Striking a balance between over and underwatering is difficult. Spinach is usually watered once weekly, but the right frequency can vary depending on your specific conditions.
  • Make sure the temperature is ideal and consistent. The optimal growing temperature for spinach ranges between 50⁰ F and 60⁰ F (10 and 15.5°C). While the plant can thrive even when the climate is a bit cooler or hotter than that, you still want to make sure you’re protecting your spinach plant from extreme temperature fluctuations, as those can quickly cause stress and, in turn, cause it to bolt.
  • Choose bolt-resistant varieties from the start. Not all spinach species are created the same. They differ in taste, size, color, and, you guessed it, bolt resistance. According to a study conducted by Oregon State University, the most bolt-resistant species are Correnta and Spinner. Getting good-quality, non-stressed seedlings that are bolt-resistant can make your job much easier.
  • Use mulch. I cannot stress the importance of using mulch enough. Mulch helps the soil retain moisture without becoming waterlogged, helps keep weeds at bay, and, as it turns out, can help prevent bolting too. Since the extra material helps insulate the soil and roots better, your spinach will be less prone to temperature fluctuations and less exposed to the elements and, in turn, less likely to experience stress.


If it’s your first time trying to grow spinach, know that it’s normal for it to grow up to 1 or 2 feet (30 cm to 61 cm) tall. However, if it gets any taller, there might be an underlying issue. Potential reasons include failure to harvest at the right time, improper growing conditions, or hormonal dysfunction. 

Knowing the right time to harvest spinach is imperative when it comes to keeping it from overgrowing. So, if you want to enjoy your fresh, delicious spinach, make sure to harvest it as soon as its height surpasses its width.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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