There are so many spinach varieties and they all look, taste, and behave slightly differently from each other. An important difference between the varieties of spinach is found in the flowering or bolting. Flowering and bolting happen at very different times for different spinach varieties and that is exactly what this post is about. So when does spinach flower?
Most spinach varieties begin to flower when they have light for at least 14 hours per day or the temperature exceeds 75 F (24 C) but some varieties flower faster than others. When spinach flowers, a long stalk grows from the center of the plant. You can sometimes delay flowering by removing this stalk.
In this post, you will learn exactly when spinach flowers and what you should do when it happens. You will also learn some tips and tricks that I personally use for delaying the flowering process or for harvesting the seeds from my spinach when it bolts.
When Does Spinach Flower?
Spinach grows very well outdoors from around April or May until September or October, depending on your region, and can be grown indoors in pots all year.
In the summer, when the days are long and the temperatures high, spinach will begin to flower. The flowering process in spinach is often also referred to as bolting and is essentially the production of seeds.
Spinach will begin to bolt when they receive sunlight for more than 14 hours per day and the temperature becomes higher than 75 degrees F (24 degrees C).
The ideal temperature for most spinach varieties is between around 50-70 degrees F (10-21 degrees C). At these temperatures, the spinach plants will grow rapidly and produce lots of spinach that you can pick and if you pick the leaves one by one rather than the whole plant at the same time, it will keep growing and producing for a long time.
If you want to grow spinach and avoid that it bolts for a long time, It is a good idea to grow it in the spring before the days become too long and especially in the fall, where the plants generally won’t bolt since the days don’t become longer and warmer.
Personally, I like to grow spinach from as early as possible in the spring to as late as possible in the fall. I usually start planting the seeds in April and then I like to start a few more plants every week or so until October. That way I can have fresh spinach for the entire growing season. If it flowers, I just remove the plant and start a new one. Spinach grows fast and can often begin to be harvested after just a few weeks.
How to Know When Your Spinach is About to Flower
It is often quite easy to tell if spinach is starting to bolt but if you want to stop it, you have to catch it before it’s too late which can sometimes be tricky so here are some things to look out for:
- The whole structure of the plant begins to change.
- A long, thin stalk with small flowers begins to grow from the center of the plant.
- The leaves begin to change shape from round or oval to pointy or arrow-shaped.
- The leaves begin to taste bitter.
- The plant becomes taller.
- The plant begins to produce seeds.
- The plant slowly begins to dry out and turn brown.
After just a couple of days into the bolting process, the entire plant will look completely different and be much taller and skinnier than before and the long stalk with flowers will begin to become full of small seeds. Some time after that, the entire plant will begin to become brown and dry.
I found this great video, where all of this is described in a very good and understandable way so if you have 3 minutes, I recommend taking a look, otherwise, feel free to skip it.
If your spinach plant begins to flower, it is not necessarily a bad sign but not necessarily a good sign either. It depends on what you want to do, so let’s take a look at that below.
What to do When Your Spinach is Flowering
There are a couple of things you can do when your spinach begins to bolt but it depends on what you actually want.
If you want to prevent (or at least delay) bolting, you can do so by removing the thin stalk from the middle of the plants but you need to be quick and do so before the leaves begin to change shape and become bitter.
You can also let the plants go through the entire process of flowering and bolting until they produce seeds that can be harvested and planted next year.
If you want to harvest spinach seeds, you should let your plants grow until the entire plant begins to become brown and dry. The seeds can be found all around the end of the long stalk that grows from the center of the plant and when the seeds are also starting to become brown and dry, you can easily pick them and save them in a dark, dry place until you are ready to plant them.
If you have no intentions of saving the seeds from your spinach, then there is no reason to keep the plant once the bolting process has started, so just pull it out of the soil and plant something else.
How to Prevent Spinach From Flowering
The best way to keep spinach from flowering is to keep the temperatures below 70 degrees F (21 C) and above 30 F (0 C).
Another thing you can do to prevent your spinach from flowering is quickly removing the stalks from the center of the plants, as soon as they appear.
When the stalk appears, things usually happen quite fast so during the warm months with lots of sunlight and heat, you may want to look for them every day and even then, this method usually merely delays the flowering process rather than actually preventing it.
Since temperature is not always easy to control, especially if you are growing your spinach outdoors, it can often be a good idea to pick a variety that will flower slower than other varieties.
According to Johnny’s Selected Seeds, some of the slow-bolting spinach varieties include:
- Emperor
- Corvair
- Woodpecker
- Lizard
- Seaside
- Red Tabby.
So if you have the option and want to try a spinach variety that flowers slower than other varieties, you could try one of these and otherwise ask a local gardener about what varieties are good to grow in your specific area.
