It's important to give plants the space they need to grow large, healthy vegetables. Lettuce is a little tricky to space only because there are so many options. From baby greens to looseleaf to heading varieties, each style will be spaced differently. As a rule of thumb: the longer the growing season the more space it should get.
Baby greens, or cut and come again lettuces, will be harvested within a very short growing season. This timeframe doesn’t really allow for mold or fungus to contaminate the vegetables. Additionally, the plants will be small when harvested. For these reasons, there’s no need to thin or space baby greens. They will grow packed together and do just fine that way. This hands-off technique is a popular option for gardeners and farmers looking for low-labor plants.
The spacing of looseleaf lettuce depends on how you will harvest it. If you plan on taking the outer leaves off and leaving the plant to grow, then spacing them is less of an issue. These lettuce plants can be as close as 3 inches from each other. You will be making room toward the bottom when you harvest the leaves allowing for adequate airflow. Plus, developing a head isn’t your goal with leaf harvesting.
If you would like to harvest heads from your looseleaf lettuce plants, give each plant the space it needs to grow that head. Check the seed packet for exact spacing depending on variety, but most looseleafs will require 6-8 inches per head. Remember that lettuce enjoys some shade, and it likes the soil around it to be cool. Packing them closer allows them to shade and cool each other.
Crisphead lettuces like Romaine or Iceberg have the longest growing season and require the most amount of space. Each variety may be a little different so check the seed packets. As a general rule, though, space heading lettuces at least 10 inches apart. Some varieties will call for 18 inches and others only 8 inches. It depends on how susceptible they are to various fungi and disease.
Because you’ll be spacing crisp heads so far apart, there is bound to be bare soil between each head. Mulch this area to lock in moisture and keep the roots cool under the sun.
Here is a simple guide to lettuce spacing:
- Baby Greens – no thinning required
- Looseleaf leaf harvest – 3-4 inches
- Looseleaf head harvest – 6-8 inches
- Crisphead – 10-18 inches
When planting lettuces between companions like brassicas or tomatoes, give them about 8 inches from the larger plant. The companions will have their own space needs. Use the seed packets as a guide and then experiment from there. An 8-inch spacing allows the companions to provide shade and distract pests but still provides for good airflow.