Salad Gardening
Published November 7, 2022 by Nicole Burke

How to Grow Your Own Romaine Lettuce

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romaine lettuce
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How to Grow Your Own Romaine Lettuce

Growing Romaine from Seed Is Easy

I'm guessing you've probably eaten your fair share of romaine lettuce, also known as cos lettuce in other English-speaking parts of the world. It is, after all, one of the four most popular types of lettuce (along with crisp head, butter head, and loose leaf) and has long been the star of Caesar salads.

And it's popular for good reason. Romaine is one of the hardiest salad greens that you can grow. Not only can it withstand both hotter and colder temps than some of the other more tender leafy greens, it's also more durable after harvesting, making it an easy leaf to put on grocery store shelves.

That being said, you haven't really tasted romaine until you've had it fresh from the garden, not trucked in from California or Arizona, where 99 percent of all the romaine found in our grocery stores is grown. Not only are you getting leaves at the peak of their flavor and nutrition when you grow and harvest your own, you're also cutting down on food miles and fuel usage. You're going to get leaves that taste so much better than ones that have been sitting in a plastic box for two weeks.

So, try to romaine calm when I tell you how easy it is to grow one of the most popular kinds of lettuce right in your own backyard (or on a balcony!).

Added bonus: you don't have to worry about all those E. coli and salmonella recalls on the news when you grow your own.

(Prefer to listen? Check out episode 6, "Romaine Calm", of the Grow Your Self podcast here.)

benefits of romaine lettuce

A Brief History of Romaine Lettuce

Romaine is also called cos because it was said to have originated on the Greek Island of Cos.

Egyptians were growing their own romaine lettuce at least 6,000 years ago. We know this because they were showing off their lettuce in their hieroglyphics. Romaine then spread throughout the Middle East and Europe. In 1492 when Cristopher Columbus showed up to the new world, he brought romaine lettuce seeds with him.

is romaine same as cos

Romaine Lettuce Growing Guide

How to Grow Romaine Lettuce

Lettuce varieties fall into two categories: loose leaf and those that form a head. Romaine produces more and more leaves around a tight center to form a fairly compact head, but as you'll see, you can still harvest from it like you would a loose leaf lettuce plant. (That means you get to enjoy leaves much sooner!)

Here are five things to keep in mind when planting and growing romaine lettuce from seed.

romaine growing

Romaine Growing Tip Number One

Plant Romaine Lettuce in the Cool Season

Romaine grows really well during the cool season (it loves temperatures between 45 and 75 degrees F), but unlike a lot of other lettuces, romaine can usually tolerate some heat. It's best to grow romaine in the spring and the fall. In the spring, wait until the threat of frost has gone.

You can start romaine from seed in the garden or indoors before your final frost date. If you're starting it indoors, keep in mind that it will be a bit fragile to transplant into the garden later on.

If you’re trying to grow romaine into the warmer parts of the year, plant some taller plants around it to give it some shade. Once it grows too hot outside, your plant will start to produce a milky white substance, which doesn't harm you but will affect the flavor. You'll also notice a change in the plant's shape once the conditions are no longer optimal for growth. These changes happen because the plant is bolting and focusing only on seed production. When this happens, it's time to toss your plant in the compost bin and start again when the weather gets cooler.

Romaine Growing Tip Number Two

Grow Romaine Lettuce in Nutrient-Rich Soil

You have two options for growing medium for your romaine. You could create a sandy loam soil mix that will appeal to all your leafy greens. If you're not sure what sandy loam soil is, don't worry. Our comprehensive Salad Garden Guide goes into all the details you need to set up your own productive salad garden, soil and all. If you're looking to simplify, you could also just grow your romaine in 100 percent compost.

romaine how to grow

Learn the step by step to plant, set up and grow your own organic salad garden and enjoy fresh greens at least six months each year

This extensive Salad Garden Guide was developed from Gardenary's online course: Salad Garden School. 

In this ebook, you'll learn the step by step for every part of developing and growing (and troubleshooting) your own organic salad garden in a raised bed or other container. 

Romaine Growing Tip Number Three

Pack in Your Romaine Plants

Lettuce plants are small, even romaine, which you might think of as a bigger lettuce. The roots don't take up much space below ground, and the leaves have a compact, upright growth habit above ground. You can grow at least nine plants per square foot of garden space as long as you plan to harvest the older, outer leaves regularly. This will ensure your plants still get plenty of air flow.

I love to grow romaine and other salad greens in a little salad garden planter I made from a steel container Many would-be-gardeners think they have to go big or go home in the garden, when really, there are so many easy and small ways that allow you to get started right away.

If you're making your own salad garden planter, make sure to add drainage holes at the bottom if your container doesn't already have them. Lettuce plants don't like to sit in water for too long. Find the complete step-by-step to create your own salad garden planter here.

romaine grow guide

Romaine Growing Tip Number Four

Protect Your Romaine Lettuce Leaves from Garden Pests

To protect your romaine from pests like earwigs, slugs, cutworms, or even squirrels, it's a good idea to cover it with garden mesh.

The key is to cover your salad garden from the moment you first sow your lettuce seeds. Young plants are particularly vulnerable to pest pressure, but garden mesh will give them all the protection they need from the get-go.

Garden mesh has the additional benefits of helping to lock moisture in your raised beds (which romaine will love) and providing some shade and shelter from strong winds and other harsh weather conditions.

garden cover over leafy greens to protect from garden pests

Romain Growing Tip Number Five

Harvest Romaine Leaves from Your Plants Frequently

Romaine needs 70 to 75 days to grow a full head, but you can begin harvesting leaves from the outside of your plant sooner than that.

Treat your growing romaine plant as a cut-and-come-again salad green by cutting leaves one at a time. Always take the oldest, more mature leaves from the outside of the plant to encourage your plant to keep producing new leaves for you from the center. Give each plant time to recover after a harvest before you cut more leaves. Continue harvesting from your romaine plant this way during the optimal growing window because this is when the leaves will taste their sweetest.

Speaking of the sweetest-tasting leaves, the best time of day to harvest from your lettuce plants is early in the morning. This is when the leaves will be in peak flavor.

Once you're nearing the end of your cool season, you can harvest the entire head of romaine. Grab the leaves like you're gathering hair for a ponytail, and cut the entire plant at the base. This is how the heads you purchase at the grocery store were harvested. When you harvest the entire head, you may get one more set of leaf growth from the center of the plant, but it's unlikely you'll get a lot of further production.

Overall, you'll end up getting more leaf production from your plants when you harvest regularly from the outside using the cut-and-come again, loose-leaf method. Harvesting this way allows me to eat a salad from the garden a day for six months of the year.

romaine lettuce leaves

What Is the Nutritional Benefit of Romaine?

If you're concerned about eating too much kale or spinach, romaine contains a much smaller amount of oxalate, which can be difficult for those with compromised gut health, and because it's less fibrous and higher in water, it's easier on your digestion. Plus, there's more than 100% of your daily vitamin K needs in a single serving of romaine, not to mention tons of folic acid, vitamin C, and minerals.

When you eat romaine fresh from your garden, the leaves will be packed with more nutrients than those leaves that have been picked in one of only two places in the United States, wrapped in plastic, trucked to your grocery store, and plopped on a shelf to sit for who knows how long.

To enjoy the full goodness of romaine, add it to your sandwiches for a bit of crunch. You can blend it into your smoothies or keep the ribs attached and add the leaves to stews. It's good for so much more than Caesar salads.

the nutritional benefits of romaine lettuce

Why Does Romaine Lettuce Get Recalled So Often?

Remember that we actually get about 99 percent of our lettuce from two places: California and Arizona, where temperatures are just right for lettuce plants. Most of the lettuce you've ever put in your mouth has been packaged up and traveled a long way to you. (If you're wondering how it stays fresh, it's all about the packaging. Greens release CO2 once they're cut, so they have to be packaged quickly and the packages need to have holes at the bottom to let the CO2 gas out.)

Now let's talk about E. coli. It's a strain of bacteria that can cause us to get really sick, and if you pay attention to the news, then you know that breakouts occur at least once a year with romaine lettuce.

The reason has a lot to do with the way our salad is grown. Since so much of our lettuce is grown in just two places, when there is an outbreak, they have to tell the entire country to throw away their lettuce because the bacteria from one spot could potentially be spread throughout the entire county. It's almost impossible for farmers to look back and pinpoint where the contamination originated from.

Plenty of veggies can be exposed to bad bacteria, but it's an extra problem with romaine because we don’t often cook it. Romaine is best when it’s fresh and crisp, but that doesn't give us a chance to remove contamination.

With the food system that we've developed, recalls and outbreaks are going to continue to be a problem. The only way to change that is by making our lettuce sources more localized to the customer. For instance, if we had lettuce growers in the Carolinas and in Texas, in addition to California and Arizona, we could better isolate issues.

This is why it is so important to start shopping locally. When you’re buying lettuce from your local farmers, you are cutting down on plastic and food trucking, and your lettuce is going to taste way better. You'll also be promoting more locally sourced foods, which could save us all from having to toss out bags of lettuce in the future.

Food Fight

Iceberg vs Romaine Lettuce

Lettuce is good for you no matter what. I grew up eating iceberg pretty much every week. In fact, I think it was the only green lettuce I ate, which is probably why I think of it as the lettuce of the 80s.

Let's see how these two lettuces shape up against one another.

Romaine lettuce contains tons of beta carotene and has more vitamin A and vitamin K than iceberg lettuce. Iceberg lettuce is more cost-effective to buy and has a longer shelf life than romaine. It has a crispier, crunchier texture.

So, if you're looking for something to stick in a drawer and last a while, iceberg is for you. If you're looking for a lettuce that is more nutrient-dense, romaine is your girl.

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In this 6-part online course, I’ll teach you what to do each and every week during a six-month period so that you can harvest your own fresh, delicious, and nutritious leaves on a weekly basis and fall in love with garden salads. This course is waiting for you inside your Gardenary 365 membership, along with our complete Gardenary online gardening courses library.

Grow Your Own Romaine

Lettuces are one of the best plants to start off with in the kitchen garden. They grow quickly, don't take up a lot of space, and provide harvests again and again. In fact, you can easily regrow your own romaine lettuce from a store-bought head. Here's how! Once you fall in love with watching those nutrient-dense leaves grow in so fast, you'll be ready to start your own lettuce plants from seed.

For more leafy inspiration, check out our top ten salad greens to grow in the garden. If you still don't have your salad garden set up yet, here are the best containers for growing salad greens.

Here's to filling up on lots of romaine in the future!

How to Grow Your Own Romaine Lettuce