Skip a Trip to the Grocery Store and Grow Romaine Lettuce at Home—Here's How (2024)

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How to Plant Romaine Lettuce

When to Plant

Romaine is a cool-weather crop and does best in temperatures that range from 60°F to 70°F. Plant two to three months before the first frost, if planting in the fall.

For spring planting, start the seeds indoors about two months before the last frost, then transplant the seeds into the ground when there’s no more chance of frost.

Selecting a Planting Site

While full sun is preferable, Romaine lettuce can tolerate some shade, like most lettuces. Select a spot that receives at least six hours of sun. Well-drained soil is important for the successful growing of this veggie, so be sure to amend the soil with compost if additional drainage is needed.

Spacing and Depth

Space seeds 12 inches apart and at a depth of ¼ inch. If you’re working with seedlings, space them 18 inches apart and use the depth of their growth in the pot as a gauge to measure the depth needed in the ground.

Plant Care

Light

The best spot for growing Romaine lettuce is one that receives full sun, though romaine can tolerate partial shade in some climates. For best results, choose a location that receives no less than 6 hours of sunlight a day.

Soil

To give your Romaine lettuce the best foundation possible, opt for loose, well-drained soil that is nutrient-rich. It’s best to amend your soil with compost to provide the best growing conditions.

Water

The plant will require regular watering, particularly when it hasn’t received rain. Use a layer of mulch around the plant to keep the soil moist but not wet as this could lead to leaf rot. Mulch will also aid in keeping away weeds that could jeopardize the soil’s water supply and nutrients.

Temperature and Humidity

Romaine lettuce can be a bit more tolerant of heat than other lettuce varieties, though it is still a cool-weather plant, thriving in temperatures that range from 45°F to 75°F. If you’re planting in the spring, avoid planting when there is still the threat of frost.

To protect your plant from excessive heat, which could damage your Romaine as well as affect its flavor, consider surrounding it with taller plants that could provide some shade in the hottest parts of the day.

If your Romaine starts to bolt (produce an elongated flower stem) or begins producing a white sap known as lactucarium, chances are, the climate has become too hot. In this case, it’s best to harvest your lettuce and plant again in the fall.

Fertilizer

The best time to fertilize Romaine lettuce is when it’s in a growth period. A balanced fertilizer of nitrogen, phosphate, and potassium (NPK) will provide this rapid-growing vegetable with the necessary nutrients for success.

Pollination

Romaine lettuce, like other members of the Asteraceae, is a self-pollinator. To harvest seeds, you’ll have to allow the plant to grow into the flowering stage where you can then pick off the fluffy white blooms that look like dandelions.

Allow the seed heads to dry for a few days in a paper bag with open air flow. Once dry, store them for the next planting season in a cool, dark, and dry place.

Types of Romaine Lettuce

• Baby Romaine: Baby Romaine is simply Romaine lettuce that is harvested early to produce more compact, crunchy lettuce. Romaine that is grown for this early harvesting purpose will oftentimes be planted more tightly than Romaine where the grower intends to let it grow to full maturity.
• Monte Carlo Romaine: The dark green leaves and compact nature of Monte Carlo Romaine create handsome foliage with a more concentrated flavor.
• Red Romaine: The leaves of red Romaine start green but mature into a deep red. The leaves produce a sweet flavor and aren’t as susceptible to bolting as other Romaine varieties.
• Paris Island Cos: Crunchy and sweet, Paris Island Cos is a quick grower with pliable leaves that are ideal for use as lettuce wraps or other applications that put the full stem to use.

Romaine Lettuce vs Iceberg Lettuce

Romaine lettuce and iceberg lettuce are both popular greens that deliver a refreshing crunch whether in salads, garnish, or used as wraps. While they can usually be used interchangeably, there are notable differences when it comes to size, shape, and color.

It’s easy to spot the difference: Iceberg features pale green leaves that grow in a round formation, whereas Romaine lettuce grows in an upright position with dark green, elongated leaves. As far as shelf-life, iceberg has the edge thanks to how long it can hold onto its crisp nature.

Harvesting

Romaine can typically be harvested somewhere between 60-80 days after planting from seed. By then, the plant can range anywhere from 8 to 12 inches tall.When the plant is about 8 to 12 inches tall and has dark green foliage it's time to harvest.

Hold all the leaves in your hand and use a knife to cut the head an inch and a half above the base. This method is ideal for the end of the season as you’re unlikely to get much continued growth from the base once the head has been removed.

To get more from your harvest, opt for removing singular leaves before the plant reaches full maturity, though this strategy is only best for times of optimal growth conditions. Simply cut the most mature leaves on the exterior of the head and be sure to give the plant time to recover after each cutting before returning for more.

No matter which method of harvesting you choose, it’s a task best suited for the morning when the Romaine is most crisp.

Before storing, wash the leaves, then wrap loosely in paper towels, and place the bundle in a zip-top bag and into your refrigerator’s crisper drawer.

Growing in Pots

Because lettuce has a rather compact root system, it makes an ideal crop to plant in pots. Plus, it’s a great way to keep a small crop if you’re not ready to commit to in-ground or larger raised-bed applications.

Each plant will need to be placed around 6 to 8 inches apart and will need a depth of about a foot, so choose a container that suits the specifications based on how many plants you intend to grow.

Natural materials are best for growing Romaine. Opt for outdoor-grade options like terracotta, steel, or cedar. You’ll also want to ensure the pot or container has plenty of drainage holes to keep excessive moisture from settling in.

How to Grow Romaine From Seeds

Romaine seeds should be sowed about ¼-inch deep and spaced about 12 inches apart. Once the plants have reached about 4 to 6 inches in height, thin the crop by removing the less hardy seedlings so the remaining plants are spaced about 18-inches apart.

Be sure to water thoroughly after both planting and thinning.

Overwintering

Planting lettuce in shielded planters, whether using row covers, tunnels, or cold frames, can help protect your crop from harsh winter temperatures and frost while still allowing tender, delicious greens.

Due to diminished sunlight and airflow, overwintered Romaine may be more susceptible to pests, rot, and other infestations so you’ll need to keep a close eye throughout the season. When overwintering, it’s typically best to harvest before the plant reaches full maturity.