How Can You Tell When Romaine Lettuce Is Ready to Harvest?

You spaced out those tiny romaine seeds, you kept your garden well watered, and you watched as all those little shoots of green turned into plants pushing out more and more leaves by the day.

But how do you know when it's time to harvest romaine and make lettuce wraps with all those crunchy and delicious leaves?

Here are the three signs to look for to know when romaine lettuce heads are fully formed and ready for harvest.

You're Within the Window of the Time Guideline on Your Romaine Seed Packet

This one seems pretty obvious, but I for one have a bad habit of forgetting to check the back of the seed packet at the time of planting something.

Those time-to-harvest estimates are usually accurate within 10 days or so, assuming that you've been growing your romaine under ideal conditions (nice, cool weather, sufficient water, etc.). For most romaine varieties, it'll be about 65 to 70 days after planting from seed. So counting ahead and making note of this date on your calendar can give you a good idea of when to expect your big harvest.

The Leaves Will Be a Nice Dark Green Color

The color change when romaine plants are mature is nowhere near as pronounced as with fruit ripening on the vine, but you might notice the leaves darkening up a bit. When romaine is mature, the head will be nice and open, like a bouquet of glossy leaves. Don't expect a nice tight head like with iceberg lettuce or cabbage.

You can also gauge the size based on the variety of romaine you're growing. Little Gem romaine plants are usually about 6 inches tall when mature, while the classic Cos Romaine can grow upwards of 12 inches tall.

The Weather Is About to Change

Romaine lettuce, particularly Jericho romaine, is more heat tolerant than other types of lettuce, but most varieties will start getting stressed out when the temperatures rise above 80°F. Your plants might start producing a milky white substance, which doesn't harm you but will affect the flavor. The leaves will likely taste bitter now that the plant is bolting, or going to seed.

So if you're nearing the end of your nice, cool weather, it might be a good idea to go ahead and harvest your romaine. You might not get that full head you're after, but you'll still get lots of delicious leaves to use in the kitchen—much better than entire heads destined for the compost bin!

You Don't Need to Wait for Your Romaine to Form a Full Head to Harvest Leaves

You can actually begin harvesting those outer leaves from your romaine plants just 21 days after sowing seeds. At this point, they'll be baby greens. You can continue taking a couple leaves at a time from each plant while you're waiting on the head to form.

This works because lettuce plants push new growth from the center of the plant. Taking just the older, outer leaves allows the rest of the plant to keep on growing and doing its magic in the garden.

To harvest individual romaine leaves, pull down as you twist from the base of the leaf. Pulling upwards risks uprooting the entire plant, and that would be such a bummer!

You obviously won't get a ton of leaves all at once, but treating romaine like a cut-and-come-again salad green gives you way more leaves throughout the season. These leaves will be tender, sweet, and delicious in your salad bowl because they're harvested during the optimal growing window. Plus, removing them gives the romaine plant more energy to put toward developing the head. So don't wait on a full head to fill your salad bowl.

Another benefit of harvesting this way (besides yummy leaves much sooner, of course) is getting to pack in romaine plants much closer together. If you commit to removing outer leaves regularly, you can grow at least 9 plants per square foot of garden space.

You can see this type of spacing in the picture below.

2 Different Ways to Harvest a Full Head of Romaine

When your romaine is mature (or before the temps rise too high), you can harvest the entire head in one of two ways.

The first way is to grab the base of the plant and pull the entire thing out of the ground, roots and all. This is a messy way to harvest, and you risk disturbing the roots of neighboring plants if you're growing in a raised garden bed.

The second way to harvest an entire head is to use the serrated edge of a hori hori or sharp, clean pruners to cut right above the base of the plant. Use one hand to gently push the romaine head away from you as you cut so that you can see the base better. This is a cleaner way to harvest, but it does leave the roots of the plant in the soil. Leave about 2 inches at the base of the plant if you'd like to give it a chance to regrow.

Ta da! You have a gorgeous head of romaine that you grew yourself! Bonus: it's not covered in E. coli and salmonella like the store-bought stuff!

THE BEST TIME OF DAY TO HARVEST ROMAINE

The best time to harvest romaine, whether you're taking just a couple leaves or harvesting the entire head, is in the morning. If you must harvest during the heat of the day, dunk your romaine heads in a little ice bath to plump them back up and increase their potential storage time.

Will Romaine Lettuce Regrow After Cutting?

If you leave the roots in the soil and about 2 inches of leaves when you're harvesting a head of romaine, your plant may start to grow new leaves from the base. It's not a guarantee and you won't get a full head, but I have had some success regrowing romaine in my garden.

It's pretty mind-blowing, but you can actually regrow romaine lettuce you buy from the store. Now, you probably won't get a full head of lettuce, but you can potentially get some more leaves and even collect romaine lettuce seeds if you'd like. In the picture below, you can see different stages of romaine regrowing from the base of the plant when placed in little cups of water.

Follow these steps to regrow store-bought romaine.

How to Store Homegrown Romaine

Romaine stores pretty well after harvest, which is one of the reasons it's such a popular lettuce variety to see at the grocery store.

Pull individual leaves off the lettuce head and give them a good rinse under cool water. Pat the leaves dry with a towel. I recommend enjoying as many leaves as possible now while they're crispy, delicious, and full of nutrients. Excess leaves can be stored inside an airtight baggie in the fridge for up to 10 days.

Enjoy Your Homegrown Romaine!

You haven't really tasted romaine until you've had it fresh from the garden. Those lifeless store-bought varieties have been trucked in from California or Arizona, where 99 percent of all the romaine found in our grocery stores is grown. In addition to enjoying leaves at their peak flavor and nutrition, you're cutting down on your food miles and fuel usage a bit by growing your own. And that's what it's all about.

All right, I'll let you get to harvesting those romaine leaves. Thanks for being here and making gardening ordinary again!