When and How to Harvest Romaine Lettuce?

Whether you enjoy it in Caesar salads, as a lettuce wrap, or as a burger topping, romaine lettuce is a must-have in the kitchen and garden. Fortunately, this crunchy lettuce is relatively easy to grow, as long as you know how to properly care for it. With that said, there’s nothing more disappointing than spending time growing some beautiful romaine only to harvest it at the wrong time!

After years spent growing and harvesting both tender baby lettuce and crunchy romaine heads, I’ve learned what factors indicate it’s time to harvest. Join me as I share my tricks and tips for harvesting romaine.

How Long Does Romaine Take to Grow?

If you’re wondering when you should harvest romaine lettuce, it’s helpful to have an idea of how long it takes to grow. To figure this out, you can look at the days to maturity (DTM) on a seed packet. Lettuce like romaine is often transplanted, so the DTM typically refers to the number of days between transplanting a seedling and harvesting a full head.

If you bought seedlings at a nursery and don’t have a seed packet on hand, you can use a DTM estimate. Most varieties of romaine lettuce, including red and purple types, will be ready to harvest 60 to 80 days after transplanting. However, keep in mind that the exact amount of time will depend on the variety, as well as environmental factors including time of year, temperature, and sunlight

If you’re planting romaine seeds directly in the ground, add between three to four weeks to the DTM. That means plants will take anywhere from 80 to 120 days to reach maturity. 

If you’re planting seeds for baby romaine, you won’t have to wait as long. In this case, you can begin to harvest baby leaves about one month after sowing seeds directly in your garden.

Proper spacing lettuce will maximize your garden and your harvests, read my article: How far apart to plant lettuce?

When and How to Harvest Baby Romaine Lettuce?

If you’re hoping to harvest tender baby romaine for a salad, you have multiple harvest options. No matter which one you choose, you’ll want to use the size of the plant’s leaves as a guide. When the largest outer leaves are three inches tall, you can begin harvesting. While you can harvest when the plant is smaller, your harvest won’t result in much lettuce if you do so.

Harvesting Outer Leaves

One way to harvest baby romaine is to remove the outer leaves and leave the smaller inner leaves to keep growing. When romaine is in its baby stage, it won’t have as many leaves as a fully developed head. However, as long as the plant has three to four leaves, it’s okay to begin harvesting.

To use this method, start with a sharp knife. Look at each romaine plant and locate the outermost leaves—these leaves will also be located towards the bottom of the plant. Carefully grasp one of these outer leaves with your hand and then use the knife to cut the leaf as close to the base of the plant as possible. You’re aiming for a quick, clean cut to minimize damage to the plant.

You can continue cutting outer leaves following the same method, as long as you leave the two or three innermost leaves. These small leaves will continue to grow, and you can come back to harvest them in a few weeks.

By following this method, you can expect to harvest baby romaine between three and six times. Generally, the time of year will impact how many harvests you can make. 

In the warmer months, lettuce will begin to ‘bolt’ aka produce flowers. When this happens, the leaves become bitter and possibly tough, meaning it’s time to stop harvesting. Cooler fall temperatures prevent bolting and allow for more harvests. However, less daylight also means slower growth, so you can expect to wait more time between harvests.

Harvesting Via the ‘Cut and Come Again’ Method

Another way to harvest baby romaine is what many gardeners refer to as the ‘cut and come again’ method. As the name suggests, this involves cutting romaine plants so they continue to grow. This is the method I use to harvest lots of baby romaine at once, since it’s quick and efficient. With that said, it works best if you’ve planted a row of romaine rather than single plants.

The best time to use this method is when the plants are four to five inches tall. I’ve found that larger plants result in leaves that are a bit too big for salads and smaller leaves make it difficult to harvest so plants will regrow.

You’ll want to start with a sharp knife. Carefully grasp a few romaine plants then use the knife to cleanly cut the plants one to two inches above the soil surface. The goal is to leave the core of the plant intact so it keeps growing. If you cut right, the leaves will be ready for another harvest in two to three weeks.

When and How to Harvest Romaine Heads?

If you’re aiming for mature romaine heads with a crunchy rib and sturdy leaf, you’ll want to look for different factors than you would with baby romaine. First, use the days to maturity as your guide. This will give you a good idea about when the romaine heads will be ready to harvest.

Next, look at the lettuce itself. There’s no harm in harvesting romaine heads that are too small—you’ll simply end up with less lettuce. However, letting the lettuce grow into a dense head will provide you with lots of greens to enjoy. Before I harvest romaine, I give each head a gentle yet first squeeze. If it easily squishes into my hand, I give it some more time to grow. And if it feels dense to the touch, I go ahead and harvest.

To harvest a head of romaine, use a sharp knife to cut the base of the plant close to the soil surface. You should be left with a small stump of a stem. After you cut, you can clean off any bottom leaves that have become discolored or damaged by insects. 

When Is it Too Late to Harvest Romaine?

While harvesting romaine that is too small just means you’re left with a minuscule harvest, picking lettuce too late may result in poor taste and/or texture.

We grow lettuce to eat, but the plant’s main goal is to reproduce. And that means producing flowers and then seeds! When lettuce begins to form a flower stalk, it’s said to be ‘bolting.’

If lettuce becomes stressed by heat, drought, or insects, it is more likely to bolt. This is why gardeners and farmers often grow lettuce in the spring and fall but not the summer.

You will know a romaine plant is bolting when it begins to develop an upward, elongated shape. Over time, the plant will produce a tall, thin flower stalk topped with daisy-like flowers.

While there’s no danger in harvesting romaine that has started to bolt, the leaves will be bitter and possibly tough. Therefore, you should aim to harvest your romaine before the plant has started to bolt.

Harvest Romaine With Confidence

Now that you know how to harvest romaine lettuce, it’s time to head out into your garden with confidence! Since lettuce is a relatively fast-growing plant, you can have multiple attempts at a successful harvest each year.

Photo of author

Briana Yablonski

Briana holds a B.S. in Plant Sciences from Penn State University and has been working with plants, soil, and ecology for over ten years. She spent five years working on vegetable farms throughout the East Coast before starting her own farm in 2020. She has been writing about plants, food, and science since 2019.

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