Why Is My Lettuce Growing Straight Up?

If this is your first attempt at growing lettuce, you must be taken aback by this strange phenomenon, and may relentlessly question yourself: “why is my lettuce growing straight up?”

Well, you are not alone. When planting lettuce, most people would witness the sight of tall and straight lettuce. 

Let’s find a satisfactory answer to the above question and the methods to deal with the tall-growing lettuce.

Lettuce growing straight up and tall

Why Is My Lettuce Growing Straight Up?

What happens to the lettuce when they grow too tall?

When your lettuce plants suddenly grow overwhelmingly tall from the stem, we can refer to this phenomenon as “bolting”. 

Bolting is the term applied to vegetable crops when they run to seed prematurely, thus rendering the crops unusable.

Why so?

Once your lettuces bolt, their leaves get smaller, stiffer, and the taste turns bitter. These changes will worsen the quality of your lettuces and may render them inedible.

So what causes bolting?

Bolting is common with many cole crops like lettuce in the cold season. The premature flowering of lettuce plants reduces the sweetness of the lettuce, which is an unwanted outcome for any gardeners. 

So, what causes this phenomenon?

Although it’s widely believed that bolting is the result of high temperatures, scientists have concluded that the temperature is not the only and deciding factor through a number of experiments.

In one experiment, they divided the lettuce into two groups, one was covered at different intervals in a day and the other was exposed to sunlight all day. The result was that the second group of lettuce bolted.

In another test, they tried growing some lettuce plants at 90°F for eight consecutive hours under the sunlight. In the end, there was no lettuce bolting. 

Other studies show that lettuce didn’t bolt until they had been planted for 135 days in January when the daytime was short. Meanwhile, lettuce grown in July bolted only after 90 days.

From these experiments, the scientists have successfully identified the exact factors causing lettuce to bolt.

In short, being exposed to sunlight is the primary cause of bolting lettuce. Besides, heat, dry conditions, and cold weather are also secondary factors contributing to the cause. 

We also want to address another related question to this problem: “why are my seedlings growing so slow?”. 

Our answer is that, if you expose lettuce seedlings at  40 – 50°F for several consecutive days, some flower buds will be formed, yet they won’t bloom until the weather gets warmer. This means that the development of seedlings with flower buds is inhibited.

Some Tips To Prevent Lettuce From Growing Tall

It is nature that causes tall-growing lettuce. So are there any ways to get rid of this phenomenon?

Unfortunately, nothing can be done to stop or prevent bolting completely, but here are some tips to resist it:

Choose the slow-bolting seeds

There are some popular brands manufacturing slow-bolting seeds on the current market like Summer Bibb or Slobol.

Though, due to adverse natural conditions, these slow-bolting seeds can only slow down the bolting process for a few days.

Minimize time exposed to sunlight of lettuce plants

As mentioned, the leading cause of bolting is exposure to sunlight for a long time. 

Therefore, you can minimize the time these plants are exposed to sunlight by placing the lettuce seeds under the shade of taller plants. Or, growing lettuce in some pots is also a good idea, for easier relocation later on when necessary. 

Don’t forget to water them every day to keep the soil moist as well as keep lettuce leaves fresh and succulent. 

Apply the deep water culture hydroponics method 

The deep water culture hydroponics has become one of the most effective methods of growing plants, including lettuce. 

Grow lettuce using deep water culture hydroponics

In this method, gardeners replace the soil with water containing essential nutrients for plants. The lettuce plants will then be cultivated in a greenhouse. The plants are guaranteed not to be exposed to strong sunlight even in the summer. 

This, therefore, not only slows down the bolting process in lettuce but also produces fresh and juicy leaves. 

Despite its relatively high cost, this method promises to bring about great results.

Can You Still Eat Bolted Lettuce?

Yes, you can. Theoretically, you can still eat bolting lettuce because there is not any poison or toxic substances.  

However, their tastes are quite bitter, which may put you off. Plus, after lettuce bolts, their nutritional content has been reduced significantly. Hence, the quality of lettuce is no longer intact.

So how can you know when lettuce is only a little bitter and still edible?

Just notice when there are only 2 – 3 flower buds, take a leaf from the lettuce plant, and taste it. At this time, the leaves may not be too bitter, so you can still eat them.

What Can You Do With Bolted Lettuce?

  1. Give bolting lettuce to animals. Several species of animals like rabbits, pigs, and birds munch on lettuce leaves, even when they bolted and became bitter.
  2. Regrow them by cutting half of the lettuce trunks. After your lettuce bolts and grows straight up, just cut to half of their trunk. Then, take care of them as seedlings. The cut lettuce plants will produce fresh crops in about several weeks.
  3. Set aside the seeds for the crop next year. If your lettuce becomes inedible and you have no idea what to do with it, wait until your lettuce plants produce seeds, then collect and set aside these seeds for your next crops of lettuce.
  4. Make compost from bolting lettuce leaves. Bolting lettuce leaves can be mixed with straw and autumn leaves to make compost. You can use these compost piles to fertilize plants or improve the soil.

The Bottom Lines

So now, “why is my lettuce growing straight up?” is no longer a mystery to you, right?

To sum up, the phenomenon “growing straight up and tall” of lettuce is not strange for gardeners. It’s just like a manifestation of the plants getting older because of natural factors.

We have also provided some tips and ways to deal with bolting lettuce for your reference. We hope these tips will make you a pro in dealing with bolted lettuces.

Thank you for reading and we’ll see you on our next sharing!