Why Is My Romaine Lettuce Growing Tall?

  • By: CarlBroadbent
  • Time to read: 5 min.
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Everybody says lettuce is easy to grow, and beginner gardeners should start off growing lettuce due to this.

While this is true, lettuce can hold some surprises for the unsuspecting gardener, which can cause beginner gardeners some concern.

One such aspect of lettuce growing is when your Romaine lettuce begins to grow tall. What does this mean in a leafy green plant?

Romaine lettuce is a tall variety of lettuce that grows leaves taller than most other leaf lettuce varieties. This is normal growth for Romaine lettuce. If the lettuce develops a tall central stalk, it is entering the bolting stage to seed, and the lettuce leaves will become bitter and tough.

Romaine lettuce can surprise the unsuspecting gardener expecting a dainty lettuce plant when they planted their lettuce seeds!

Romaine lettuce really tall
Romaine lettuce

If your Romaine lettuce is growing taller than you expected, you may question if there is something wrong with the plants or something you did wrong in your cultivation of the plant.

Is Romaine Lettuce Supposed To Grow Tall?

All the leafy green plants that we eat, such as lettuce, spinach, and swiss chard, all have a growth cycle that includes producing the luscious leaves that we eat and a flowering and seeding stage.

Romaine lettuce is supposed to grow tall. It is a naturally large lettuce variety that grows taller than most leaf lettuce plants most gardeners are familiar with. The leaves are tall, supported by a rigid central stalk that holds the leaves upright from the central core.

Romaine lettuce is the traditional lettuce used in a Caesar salad because of its large, dark green, crunchy leaves.

This variety of lettuce can grow quite tall, so that a casual glance may mistakenly identify the plant as spinach due to the height that the plant can attain.

Due to its size, Romaine lettuce requires more space between the plants to avoid overcrowding and stunted growth of the plants:

  • Romaine lettuce should be planted at least 12-inches or 30-centimeters apart to give adequate space for the large leaves of these plants.
  • The additional space allows for good air circulation in the dense leaves and prevents the leaves from rotting due to too much moisture.

Romaine lettuce is a variety that is more tolerant to heat than many other lettuce varieties, which is why it is popular among gardeners in warmer climates.

Other Reasons Your Romaine Lettuce Is Growing Tall

The leaves of the Romaine lettuce are not the only parts of the plant that can grow tall.

Towards the end of its growing cycle, or if the weather becomes too warm, the plant may bolt, producing a tall flower stalk in preparation to produce seeds.

Grow Romaine lettuce
Growing Romaine lettuce

Bolting is the term given to plants, particularly the leafy green plants when they start to produce a flower stalk in preparation for flowering and producing seeds.

Some gardeners term this process going to seed as an alternative description of this natural progression.

Why Does Romaine Lettuce Bolt?

Our leafy vegetable plants are mostly cool weather plants since their leaves cannot handle harsh summer temperatures and would lose too much water vapor to sustain the plant.

This means that when the temperature starts to get too warm, it triggers the plant to bolt, and it starts producing a flower stalk.

When the lettuce plant detects threatening conditions such as heat or dry conditions, it recognizes that its prime growing season is over. It redirects nutrients, energy, and resources from the leaves to the growing flower stalk and ultimately into the production of the seeds to propagate the plant.

Heat is not the only condition that can trigger bolting in lettuce.

Insufficient water or dry conditions can put the plant under stress and cause it to go to seed in an attempt to produce seed before the unfavorable conditions kill the plant.

The leaves suffer when the lettuce bolts and take on a shriveled, unhealthy look and become tough to eat and develop a bitter flavor.


Remember This: Leaves from a lettuce plant in the bolting stage are essentially inedible and are not suitable for your table salad!


Can You Stop Lettuce From Bolting?

As a gardener growing lettuce as part of your food crop, you want to delay the bolting of your lettuce for as long as possible to keep the plant producing large juicy, crisp, sweet leaves for as long as possible.

You can stop romaine lettuce from bolting
Prevent Romaine lettuce bolting

Once the bolting process has started, there is not much you can do to stop the plant from going to seed. The best method to delay bolting is to give the plant an environment that delays the bolting process. This will give you a longer time to harvest the leaves and enjoy sweet, tender lettuce.

Some gardeners have had success with pinching off the flowering stalk as they see it develop on the plant.

This strategy only lasts a short time, and the inevitable bolting cannot be prevented.

Even though Romaine lettuce is more heat tolerant than other lettuce varieties, it will go to seed if the temperatures are consistently hot and the plant does not get enough water.

Use these strategies to delay the bolting of your Romaine lettuce.

Time Your Planting

Planting in late winter once all chance of frost is past will give you an extended spring growing season where the temperatures are not too hot.

In some locations, the winter is mild enough to grow this plant throughout this season.

Grow Lettuce In Dappled Midday Shade

If your summer temperatures are hot, you can try growing your lettuce in a location where it is in dappled shade in the heat of the day but gets direct morning and evening sun.

Shade cloth that allows light through but limits UV exposure can also help stop the plants from overheating and going to seed.

Water Lettuce Regularly

Lettuce can also bolt if it experiences water distress.

The soil around the lettuce must always remain moist.

The top level can dry a little, but the plant will bolt if the soil at the root level begins to dry.

Conclusion

While Romaine lettuce is a naturally tall lettuce variety, most leaf generation should happen quite close to the ground.

If your Romaine lettuce starts to produce a tall central stalk, it is in all likelihood beginning to bolt.

This indicates that the plant is at the end of its life cycle and is about to produce flowers to produce seeds.

At this point, the lettuce will no longer be good to eat.

The best option is to let the plant flower and produce seeds, collect them, and replant them in a cooler location.

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