Plant Herbs, Onions, and Fruiting Plants with Your Romaine Lettuce

Q: What do you call a raised bed filled with nothing but romaine plants?

A: A pest's dream home.

The truth is, those tender leaves are just too tempting to leave out in the open without other plants there to distract or deter the pests. If you really wanted to plant a raised bed with just lettuce, you'd want to keep it covered with garden mesh at all times to keep pests out.

Short of covering, your next best organic pest control option is companion planting with your romaine. Ideally, you'll add in plants that either repel pests or attract beneficial insects to your garden to prey on those pests. These plants also need to grow in the same season as romaine, of course, and not be bothered by regular watering.

In retune, romaine makes a good companion for lots of different plants. It has shallow roots and doesn't grow very tall, so it won't block light from other plants trying to grow in the space. Let's look at how to companion plant with romaine.

How Does Romaine Lettuce Grow Best?

Romaine is hardier than other salad greens, including pretty much every other type of lettuce—crisp head, butterhead, and looseleaf. Even so, it's best to keep these four things in mind when you're planning out your garden beds.

Romaine TEMPERATURE PREFERENCE

Romaine loves cool weather (temps between 45°F and 75°F) but can push into warmer months. Most other types of lettuce will bolt, or go to seed, once the weather warms. Romaine is typically grown in the spring, after your last frost date, and again in the fall.

Romaine SUNLIGHT NEEDS

Romaine and other types of lettuce really only need 4 hours of sunlight a day to produce leaves for you. They prefer the shorter days of spring and fall, so they're perfect to grow alongside other plants that like shorter days, which includes spinach, radishes, and carrots.

Romaine NUTRIENT NEEDS

Romaine loves growing in the same sandy loam mix that most other vegetables prefer. Like other leafy greens, romaine can also grow in straight compost, but that wouldn't be a good growing medium if you'd like to grow romaine alongside root crops and fruiting plants.

Romaine WATERING PREFERENCES

Lettuce plants are mostly just water, so they need a lot of water to sprout and grow. Even once they're established, they like consistent moisture, which makes them great neighbors for root crops like beets and radishes.

My Favorite Types of Plants to Grow with Romaine

The cool season is my favorite growing season in the garden. Lettuce plants are pretty much my favorite thing to grow period, but I also love all the leafy greens, herbs, and root crops that grow alongside them.

When you're growing leafy greens, one of your main goals of companion planting should be to add some protection for all those leaves against pests and disease. The two key plant families to boost your garden protection are alliums and herbs from the carrot family.

Romaine Plants and Alliums

Alliums, or plants in the onion family, include onions, garlic, leeks, shallots, and chives. Each of these makes a beneficial companion plant to the salad garden. The reason being is that this family has a particular smell, and that smell is so strong that it can deter pests that are interested in munching on your leaves. It's really an effective form of organic pest control. If you look around my kitchen garden, you'll see an allium next to just about every single leafy green, romaine included.

Romaine Plants and Herbs

Some of the best herbs to plant near romaine are cilantro, parsley, and dill (all herbs in the carrot family). You can, of course, harvest these herbs and toss their leaves into your salad bowl to add more flavor, but the plants themselves are actually great companions for salad plants. These herbs have gorgeous little flowers that attract beneficial insects like ladybugs, and they do a lot of good for the health of your garden as a whole.

You can also grow romaine next to any herbs from the mint plant family (think basil and then all the perennial herbs like rosemary, sage, oregano, and thyme). Some gardeners swear that basil makes lettuce taste even better.

Romaine Plants and Root Crops

You know how slices of radishes and carrots taste so good in your salad bowl? Well, these root crops grow really well in your salad garden, too. Not only do they have similar growing preferences, radishes, beets, and carrots can break up compacted soil to make it easier for tender lettuce roots to spread out. Radishes and beets can help protect your greens from pests like aphids and flea beetles, and if you let a couple of your carrots flower, they'll attract ladybugs and lacewings, which eat aphids.

Romaine and FRUITING PLANTS

The best fruiting plants to grow in the same beds as romaine lettuce are peas and strawberries. Peas fix nitrogen into the soil, and as you may know, leafy greens like lettuce need lots of nitrogen to grow healthy leaves. Peas growing on a trellis might also provide some shade for lettuce plants during warm afternoons.

Strawberries produce gorgeous little flowers that attract beneficial insects like predatory mites and parasitic wasps.

Other fruiting plants like tomatoes, peppers, and cucumbers grow well with romaine, but they'll typically only share gardening space with your more heat-intolerant lettuce plants while you're transitioning from a cool season garden to the warm season and vice versa.

Romaine Plants AND FLOWERS

You've probably caught on that flowering plants can be really beneficial to our little lettuce babies. Calendula, chamomile, and marigolds love cool temps and even come from the same plant family as romaine and all our favorite lettuces, the Asteraceae plant family. Calendula will actually act as a trap crop and keep aphids off your lettuce leaves.

Another great flower to add to your salad garden is nasturtiums. These guys attract beneficial insects and deter other pests. Plus, their leaves and flowers are edible and add some fun color and texture to your salad bowl.

What Would a Raised Bed Filled with Romaine and Good Companion Plants Look Like?

The planting plan below for a 4' x 4' raised bed has pansies and chives planted in each of the corners. That way, the raised bed looks nice and enticing to beneficial insects (and you) and already has some alliums to deter pests.

Radishes and green onions grow in rows along either side of the bed to further deter pests. That leaves kale, which will grow tall, in the middle and a little belt of a heading lettuce like buttercrunch or romaine to grow around them. If you have some obelisk trellises, you could swap the kale plants in the middle for two obelisks supporting sugar snap peas. This right here would be a really beautiful and productive bed.

Can Romaine and Iceberg Lettuce Grow Together?

Different lettuce varieties grow really well together, which is why we can have things like spring mix. Since romaine and iceberg are both heading lettuces, you just want to make sure you're giving them enough space to grow. I typically plant about nine heading lettuces per square foot of garden space, but that tight spacing means I need to come in and harvest the outer leaves from those plants regularly.

Are There Bad Companion Plants for Romaine?

Besides radishes, brassicas don't always make great companions for lettuce. Cabbage, broccoli, kale, and kohlrabi all require similar nutrients to grow and produce leaves, which means they're in direct competition with lettuce plants. Broccoli and mustard greens can also release chemicals that inhibit the growth of other leafy greens around them.

I still grow lettuce with brassicas like kale and cabbage, as you can see from the planting plan above. Just be prepared to add some more nitrogen to the soil if any of your greens are slow to grow or appear to be struggling. It's also a good idea to plant a wide diversity of plants around them. That's always the case. Just have lots of other plants in the mix to counter any negative effect from a couple of plants.

Fill Your Garden with Leaves, Roots, and Fruit!

I hope this helps you fill your garden beds with lots of things that grow well with your lettuce babies. Growing leafy greens with your favorite herbs, root crops, fruiting plants, and flowers keeps your garden productive and interesting because there's always something to cut and tend. Those lettuce plants will sure keep your harvest basket full while you're waiting on your large and longer plants to produce.

Thanks for being here and helping to make gardening ordinary!