If you’re interested in growing your own lettuce at home, you might be wondering how far apart to plant the lettuce seeds. Before you can answer this question, it’s important to understand the three main types of lettuce- loose leaf, butterhead and crisphead.
Depending on which type of lettuce you choose to grow, you’ll need to space and thin the seeds a little differently.
Loose leaf lettuce is the most popular lettuce among home gardeners because it grows quickly with a wide seasonal planting window. Loose leaf lettuce does well when seeded at no more than 20 seeds per foot in each row. Rows should be 12 to 18 inches apart each. When the plants sprout, you’ll want to make sure to thin them at least 4 inches apart each.
While slightly less common among home gardens, butterhead lettuces boast sweeter, thicker leaves that often take on a slightly yellowish color, hence the “butterhead” nomenclature.
These lettuces have very flexible leaves similar to loose leaf lettuces, however high temperatures can alter their flavor and cause them to become bitter. This means more care and attention is needed throughout the growing process, making them more of a challenge for amateur gardeners. Much like their loose-leaf counterparts, butterhead lettuces do well when planted at 10 to 20 seeds per foot, thinning the individual plants out to at least 4 inches apart after sprouting.
The third main type of lettuce, crisphead, is notorious for being the most difficult to grow of the three. This is because sustained, cool temperatures are a necessity for growth. Even slight temperature increases can cause the lettuce to go to seed, rendering the leaves tough and bitter. If you endeavor to grow this challenging cultivar in your home garden, it’s best to give crisphead lettuces a little more room, sowing no more than 10 seeds per foot and thinning individual plants anywhere from 10 to 12 inches apart.
Lettuce Spacing vs. Yields
A 2017 study conducted in Ethiopia sought to examine the effects of inter- and intra-row spacing on lettuce yields. Researchers planted lettuces in rows that were 60 and 70 cm apart from each other. Within these rows, they planted the lettuces themselves 30, 40 and 50 cm apart from each other. They then grew the lettuce over the course of one cropping season and measured the effects of these variables on plant height, number of leaves per lettuce, leaf width and leaf weight.
Overall, researchers found that the distance between planting rows, as well as the distance between the individual lettuce heads themselves affected lettuce growth. The number of leaves grown per head as well as the width of each leaf and the weight (or biomass) of each lettuce was affected by the test treatments. Plant height was not significantly affected.
The study showed that when it comes to the number of leaves grown per head, the further apart each lettuce was from its neighbor, the more leaves it was able to grow. This is important because more leaves mean a fuller, more valuable head of lettuce.
The lettuces that grew in rows 60 cm apart grew more leaves than those in rows 70 cm apart, indicating that spacing rows too far apart might cause lettuces to grow fewer leaves. The 70 cm row spacing did however cause the lettuces to grow wider leaves in general than the 60 cm spaced rows. Lastly, the researchers found that in terms of overall lettuce yield in weight, the best spacing was 40 cm between each plant and 60 cm between each row.
When grown close together, lettuces (like most plants) experience increased root growth. Roots are essential to plant health as the main way for the plant to intake water and nutrients. However, if the lettuces are grown too close together, they will compete for light, water and resources which will decrease the overall yield and quality of the crop. Therefore, it is important to plant lettuces close, but not too close together, as reflected in the researchers’ findings.
A second study conducted in Brazil sought to determine the effects of inter-lettuce spacing. Lettuces were planted both 16 and 20 inches apart from neighboring lettuce. The results showed that the lettuces grown 20 inches apart from each other were superior in both average weight and diameter than those grown 16 inches apart.
The researchers attribute this to the decreased competition between the lettuce plants. Because each lettuce was farther away from its neighbor, there was less competition for resources such as water, sunlight and nutrients.
The researchers did find that planting the lettuces close together generated more biomass initially in the form of more leaves and higher weight. However, these conditions eventually resulted in increased spread of disease between plants as well as ground-level leaves dying due to lack of light and overcrowding.
As with the study conducted in Ethiopia, this study demonstrated that there is a delicate balance between planting lettuces too close together and planting them too far apart. You will need to experiment with your own lettuce to determine the most optimal spacing distances for your home garden.
How Far Apart To Plant Lettuce in Raised Beds
When growing lettuce at home, many gardeners plant their lettuce in rows directly in the earth. Others however grow their plants in raised garden beds, specifically designed to maximize space and improve drainage.
Raised beds are typically smaller plots of land, often only 4 by 8 feet. This means that from any given side of the bed, a gardener can usually reach to the center of the plot, or even all the way across.
Experts say that in the ideal raised bed, plants will just barely touch each other, covering all open areas of soil but not so much that they overlap each other and block out sunlight.
For most lettuce, this can be achieved by planting the heads 6 to 10 inches apart. Because you won’t be letting your lettuce bolt (flower and go to seed), the plants don’t need as much room between themselves as they would if they were intended to grow to maturity. You will be harvesting your lettuce heads when they’re leafy and tender- well before they reach their maximum size. Because of this, you can plant your raised bed lettuces closer together than you would other garden plants.
What Happens If You Plant Lettuce Too Close Together?
As demonstrated by the researchers in both the Ethiopian and Brazilian lettuce studies, spacing lettuce too close together can negatively impact the plants’ health. The main danger of overcrowding is competition between neighboring plants.
If one head of lettuce is planted too close to another the two plants will compete for a variety of resources including water, nutrients and sunlight. While one lettuce might win out and grow bigger and fuller, the losing lettuce will likely be stunted and unpalatable, if it manages to survive at all. Since the goal of a garden is to produce the maximum number of crops at the highest quality, you want to avoid this type of competition at all costs.
What Size Container To Use for Lettuce?
If in-earth and raised bed gardening methods aren’t feasible, potting containers provide a third option for growing your own lettuce at home.
Experts at the University of Minnesota recommend growing your lettuce in a one-gallon container at minimum. Two-gallon containers are better if you can accommodate the larger volume. An 8 to 9 inch container diameter is ideal, but you shouldn’t choose anything narrower than 6 inches across. These specifications should comfortably house 3 to 4 lettuce plants.
Simply increase the number of containers you are using if you want to grow more lettuce. Using the right size pot for your lettuce ensures that there will be plenty of room in the soil for the lettuce to develop a substantial root system. This also ensures that water can move freely throughout the soil so that all areas of the root system are adequately hydrated without becoming waterlogged. Overall, a properly sized container will reduce stress on your lettuce and help you grow larger, higher quality plants.
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