As you dig into the world of vegetable gardening, you'll soon hear the term bolting, especially when it comes to lettuce. But what does bolting mean? Why does lettuce do it?

The answer is simple: Bolting is when vegetable crops, like lettuce, suddenly "bolt" into rapid growth and flowering.

Bolting typically happens when a plant is stressed by poor conditions. The plant enters survival mode and tries to get to the seeding stage as quickly as possible. Unfortunately for gardeners, veggies don't maintain their flavorful taste once they flower.

Read on as we cover everything you need to know about bolt lettuce and how to prevent losing your crops to bolting.

What Causes Bolting Lettuce?

The most common cause of bolting lettuce is heat. For outdoor crops, high air temperatures are the usual culprit, but dry soil, too much sun, and lack of nutrients can also play a role.¹

Cold weather can also cause bolting in immature plants. If you see your lettuce seedlings forming buds early in the season, a spring cold snap was probably the reason.²

For hydroponically-grown indoor crops, high water temperatures are the usual cause. If your home is especially warm, air temperatures can contribute too.

Which Crops Are Prone to Bolting?

Lettuce isn't the only plant that bolts. Hot temperatures will trigger bolting in cool season greens, such as arugula, mustard greens, romaine, beet greens, and most lettuce varieties.

Other plants known to bolt are beets, broccoli, cilantro, basil and dill. Temperatures of 85°F to 90°F are the point at which nearly every lettuce variety will start to bolt.³ If you're growing lettuce outdoors, provide plenty of shade and water to prevent bolting as long as possible as the weather warms.

Some varieties of lettuce are more resistant to heat and bolt later in the season or not at all. butter lettuce, batavian, and romaine have all been found to be less prone to bolting than other types of lettuce.⁴

Can You Eat Lettuce After Bolting?

While you can eat lettuce after it bolts, you may not want to. After leafy greens bolt, the flavor becomes bitter and the leaves tend to get smaller and tougher. At this point it is inedible (unless you use it cooked in a soup or other recipes where the bitter flavor and toughness will be disguised—more on that later).

You may wonder how to trim bolted lettuce once the flower stalk has started to form. It's as simple as cutting off the flower with sharp, clean garden shears or scissors as soon as you notice the flower stalk. However, you can't stop the bolting process once it's started.⁵

It's best to harvest the leaves immediately when you see a flower stalk. You can try soaking harvested leaves in cold water overnight to draw out some of the bitter flavor compounds.⁶

How to Prevent Bolting Lettuce

The number one cause of bolting in hydroponically grown lettuce and other leafy greens is high water temperature. Follow these simple steps to prevent bolting:

• Keep the water in your AeroGarden bowl cool
• If the water feels warmer than room temperature, add cold water and or ice cubes to the water bowl
• Very rarely bolting can be temporarily slowed down if you catch it early enough and trim off the flowering stalks

What Can I Do With Bolted Lettuce?

With our tips you should be able to avoid bolted lettuce in the future. But if you've already got a crop that's flowering (or about to), here are a few things you can do instead of throwing it away:

1. For outdoor gardens, you can cut the plant back and leave the roots in the ground. In the fall, you'll get another crop of lettuce. This works best for leaf lettuces like butter lettuce or red leaf. Head lettuce usually won't grow again.
2. Use bolted leafy greens in cooked dishes. The leaves may not be as tender, but they can still be used in any recipe that calls for wilted greens. Some tasty recipes include a simple saute with garlic, butter, and onions, or a delicious cheesy gratin.⁷
3. Compost bolting lettuce plants. Your compost pile can make good use of the extra nitrogen in bolted plants.

Keep Your Greens Fresh and Delicious With AeroGarden

Following these tips should help you avoid wasted crops so you can enjoy crisp and flavorful lettuce all season long. Simply keep your AeroGarden topped up with cool, fresh water and harvest your veggies regularly to avoid bolting.

AeroGarden takes all the guesswork out of gardening by telling you exactly when to water and feed. In just a few weeks, your family will be enjoying farm-fresh lettuce and any other greens you choose, right on your countertop!

Sources:

^{1, 5} Purdue University. Lettuce bolting. https://ag.purdue.edu/department/btny/ppdl/potw-dept-folder/2021/lettuce-bolting.html

² The Spruce. How to stop lettuce from bolting. https://www.thespruce.com/what-does-lettuce-bolt-do-1402981

^{3, 6} Garden Zeus. What do you do when your lettuce bolts? https://www.gardenzeus.com/what-do-you-do-when-your-lettuce-bolts/

⁴ Colorado State University. Lettuce: Bolting resistance. https://agsci.colostate.edu/specialtycrops/lettuce-bolting-resistance/

⁷ The Guardian. How to use up wilted or bolted lettuce. https://www.theguardian.com/food/2021/jun/05/how-to-use-up-wilted-or-bolted-lettuce-recipe-zero-waste-tom-hunt

Hobby Farms. 5 things you can do with bolted lettuce. https://www.hobbyfarms.com/bolted-lettuce-garden-tips-bolt/