How to Harvest Lettuce for a Continuous Supply of Fresh Greens

Fresh, crisp, cool lettuce is the perfect addition to many summer salads and sandwiches and can be easily grown and harvested in your backyard. Gardeners will find growing a head of lettuce rewarding, but they’ll need to keep an eye on the plant for the tell-tale cracking open of the lettuce head and the beginning of a flower stalk. If the lettuce flowers, it may render the leaves inedible. Read on for tips from horticulturists about how to harvest both loose-leaf and full heads of lettuce.

Tools You'll Need

• For head lettuce: Harvesting knife
• For leaf lettuce: Sharp shears or scissors
• Basket or bowl for loose leaf lettuce
• Alcohol wipes to ensure your tool is sanitized

Instructions

Depending on the type of lettuce you’re harvesting, you’ll need different tools due to the bulk and size of the head and stalk.

Harvesting Loose Leaf Lettuce

1. Clean and sanitize your shears before making any cuts.
2. Plan to harvest in the morning to keep your leaves their freshest and minimize wilting.
3. Use scissors or shears to snip outer lettuce leaves close to the stem.
4. Place your trimmed leaves in your bowl or basket. Do not rinse the lettuce unless you plan to eat it immediately. Discard any damaged or moldy leaves in a compost bin if you have one.

Harvesting Head Lettuce

A sharp harvesting knife is needed to make a clean cut across the stalk for head lettuce.

1. Be sure to clean and sanitize your knife before using it.
2. Harvest in the morning to keep your leaves their freshest and minimize wilting.
3. Use your harvesting knife and try to cut the head of the lettuce as close to the soil as you can.
4. Remove any damaged outer leaves until you have only a clean center head.
5. Do not rinse your lettuce unless you plan to eat it immediately.

"Sometimes, you’ll get new growth from the center of the plant," says Brooke Edmunds, professor of practice and horticulturist at Oregon State University Extension. "This method is good for a bulk harvest, but you still want more lettuce later in the season."

When to Harvest Lettuce

The best time to harvest lettuce is in the morning before the sun is high enough overhead to wilt the leaves. As for general growing and harvesting, lettuce is a cool-season crop less likely to flower when the skies are gray and the average temperature is less than 85 degrees Fahrenheit.

"Harvest before the days get too warm; otherwise, the lettuce will bolt," says Edmunds. "Lettuce is an annual, and when the weather warms up, it will flower and set seed."

What Happens When Lettuce Bolts

Lettuce is a cool-season crop—it needs to be kept cool to prevent the plant from bolting. "Bolting actually changes the taste of the lettuce," says Laura Irish-Hanson, extension horticulture educator at the Department of Agricultural and Natural Resource Systems, University of Minnesota Extension. "Flowers make the lettuce more bitter."

Once you see the head of lettuce begin to "crack" open, this is the sign that the plant is beginning to flower, and the taste has likely started to change. "Taste the leaves first before you harvest and store it," says Irish-Hanson. Sometimes, If you see the center of the head crack open, you can still harvest, but you'll have to get creative with how you cook it, especially if the taste isn't past its prime. "I like to grill romaine when it does that," says Irish-Hanson.