Harvesting and Storing Lettuce
There are three basic lettuce types grown across the world. Looseleaf and Butterhead lettuce are regarded as the conventional, easy-to-grow lettuce varieties. These two are recommended for growing in household gardens. The other fresh lettuce variety is the Crisphead or the Romaine lettuce. Harvesting and storing lettuce isn't difficult but you should follow some basic instructions.
Lettuce Harvesting Basics
Most lettuces are ready for harvesting within 60 days of planting them. Every lettuce has a sizeable edible part, in the form of lettuce leaves, growing above the ground. You should know about the leaf pattern of each lettuce type to approximate the correct harvesting time:
It has a very prominent leaf head growing above the soil bed. It is advisable to harvest the Buttherheads when it seems that the head isn't developing any further. This gives the plant time to develop seeds that can be used for the next season. A mature Butterhead lettuce head can be easily cut-off using gardening scissors.
The leaf head of the Romaine variety is much smaller. It is also called the Iceberg lettuce. It has slightly elongated leaves that overlap each other to form a smaller, compact head. Ideally, you should harvest the Romaine lettuce when its head is between 6-to-8-inches tall.
This is the only lettuce variety that doesn't have a distinct head formation, i.e. the leaves may cluster but they don't form a compact head-like formation. Some cold-temperature varieties of Looseleaf lettuces may even have radiating, curly leaves in a rosette pattern. You should harvest this variety when the leaf spread is between 4-to-8-inches tall and at least 8-inches wide.
Looseleaf Lettuce Harvesting
You can harvest Looseleaf lettuce in two simple ways. The conventional method is to pick the outer leaves when they are about 2-inches long. You should do this manually, i.e. without using any pruning or gardening equipment. The picking of leaves can be done regularly for about four weeks. The other approach is to slice-off the lettuce leaves, using gardening scissors. However, for Looseleaf, cutting the leaves is slightly demanding because the leaf spread is extensive. You should cut the leaves about one-inch above the soil bed. It is critical that you leave an unharmed stub that will start growing again within a few weeks.
Butterhead/Crisphead Lettuce Harvesting
The most important consideration is to cut the leafy head near to the soil bed. You should harvest the lettuce during early mornings, as the leaves are still crisp, i.e. easy-to-cut. You can use lightweight pruning scissors for harvesting lettuce. Harvest the leafy heads that feel firm. You should unwrap the outermost leaf and try crushing it with your hand. If the texture isn't soft and it is easy-to-crush, the leaves are turning crisp, i.e. appropriate for harvesting. You should cut the external leaves of the leafy cluster, ensuring that some of the younger, inner leaves are left intact. This is vital to ensure future growth in the plant. If you have already harvested a lettuce three-to-four times, you can cut the entire head, i.e. including the inner leaves but leaving the stub.
Lettuce should not be canned or put in deep freeze. You should wash the leaves thoroughly before storing them. After washing the leaves, let them drip-dry. You should pack the leaves in plastic bags and place them in a refrigerator. The ideal storage temperature is about 32° F. If you want to preserve them for a longer period, roll the leaves in moist paper towels before refrigerating them. Crisphead lettuce is known to last the longest, often retaining its freshness for two weeks, i.e. in a refrigerator. You should ensure that refrigerated lettuce isn't placed in proximity of fruits like pears or apples as this causes early spotting of the leaves. These fruits release a ripening agent that initiates a chemical reaction in lettuce, leaving brown spots on the leaves.