Harvesting Buttercrunch lettuce (Lactuca sativa 'Buttercrunch') -- a variety of Bibb lettuce -- is as simple as cutting away select leaves or even the entire head. It's a simple process, but avoid harvesting too late or you may get bitter or tough leaves.
When to Harvest Buttercrunch
The entire head of Buttercrunch lettuce will be mature at between 55 and 70 days after planting seeds, but you can typically start harvesting leaves when the plant is just 21 days old. While it's often grown as an annual, lettuce is hardy from U.S. Department of Agriculture plant hardiness zones 4 to 9 and prefers cooler weather. Gardeners typically plant seeds both in the early spring as well as the fall, offering a harvest through much of the growing season.
When your Buttercrunch plant has formed a few leaves, you can start harvesting the baby leaves, washing them and adding them to salads or sandwiches. Cut away a few of the outer leaves of the plant and leave the inner leaves -- which are typically smaller -- to continue to grow. Do this right before you want to eat the baby leaves, as loose-leaf lettuces, including Buttercrunch, can wilt quickly.
Past Its Prime
As you continue to harvest and eat the outer leaves of your Buttercrunch lettuce, you'll probably notice if the leaves begin to taste bitter or if they begin to get tough. At that point, it's a few days past the ideal harvesting time for leaves or the entire head. Likewise, if your Buttercrunch lettuce is bolting -- sending up a long shoot from the center -- you've waited too long to harvest the entire head. Bibb varieties tend to get bitter in high temperatures. You can still harvest it and eat it, but the lettuce may not taste as tender and delicious as earlier harvests.
Harvesting Mature Heads
When nearing maturity, Buttercrunch lettuce will form a loose "rosette" or "head," and the leaves may turn slightly reddish. Plan to harvest the entire head at between 55 and 70 days after planting -- or when the leaves are full and still tender. Harvest the entire mature head by cutting the plant at its base. Leave the base in the ground, however, since it may develop more leaves that you can continue to eat.