Lettuce is one of the most versatile crops out there. You use baby leaves in salads, enjoy big leaves on sandwiches, and use tender leaves for lettuce wraps. And not only does lettuce have multiple uses in the kitchen, but it’s also easy to fit into your garden.
If you plan on growing lettuce in a raised bed, you’re in luck! Raised beds provide a great home for lettuce due to their excellent drainage and easy accessibility. However, before you plant these leafy greens in raised beds, you should keep these five tips in mind.
Pay Attention to the Variety
Seasonal planting ensures lettuce thrives year-round.
When it’s time to grow lettuce, you have almost endless options. There’s the dense, crisp romaine that’s a start of Caesar salads, tender butterhead varieties that are perfect for lettuce wraps, and crunchy crisphead that holds up well on sandwiches. You can find handfuls of individual varieties within these broad categories, making settling on a single variety difficult.
After I decide which type of lettuce I want to grow, I look at the different cultivars available. Each variety has specific disease resistance, heat tolerance, cold tolerance, and days to maturity. Finding a variety that holds the characteristics you’re looking for is a vital part of growing a healthy crop.
I like to plant a few different lettuce varieties throughout the year since each one has unique attributes. For example, I plant varieties like ‘Buttercrunch’ and ‘Vivian’ in spring since cooler days lead to supple leaves and prevent bolting. When warmer weather arrives, I switch to heat-tolerant options like ‘New Red Fire.’ While no lettuce loves the heat, some varieties can withstand summer heat without bolting and becoming bitter. Fall lettuces are often similar to those planted in spring, but I look for cold-tolerant varieties if I plant to grow the lettuce into the winter.
If you find a specific variety you like, make sure to write it down! And just because a variety didn’t grow well in July or September, it doesn’t mean it won’t grow well at other times of year. Experimenting with a few varieties each season will help you find cultivars that are well-suited to your specific climate and raised bed garden.
Plant at the Proper Spacing
Check your seed packet for plant spacing recommendations.
Once you’ve determined which lettuce variety you’ll plant in your raised bed, it’s time to figure out how much room it needs to grow. Like with most greens, you can harvest lettuce at any time. However, if you want to grow a large head of romaine or a buttercrunch that can feed an entire family, you have to make sure your lettuce has enough room to expand.
First, look at your seed packet. Most packets should give a range of numbers for adequate plant spacing. Many types of lettuce grow well 9-12 inches apart, but some can handle narrowing spacing, and others grow best at wider spacing.
If you’re growing lettuce with other crops, let the spacing serve as a guide rather than a hard rule. For example, you can tuck lettuce plants a little closer to trellised snap peas since the peas won’t interfere with the lettuce’s growth.
Finally, remember that you can grow lettuce at any size. If you want to grow baby greens for a salad mix, you can plant a few seeds per inch. Instead of planting the seeds in a dense block, plant them in rows with a few inches of space between each row. The rows save space and make harvesting easy, while the space between them allows for airflow and helps prevent disease.
Think About Temperature
Raised beds warm and cool faster than ground soil.
Growing lettuce in the ground and in a raised bed is pretty similar. However, one of the biggest differences between these two growing environments is their soil temperature.
Since raised beds are exposed to the air, the soil warms and cools faster than the soil in the ground. That means raised beds warm up quicker in summer and cool down more rapidly in winter. It also means that the beds experience larger fluctuations in temperature between the day and night.
So, what does this mean for growing lettuce? Well, if you’re growing in a raised bed, expect lettuce to bolt more quickly in summer and freeze faster in winter. You can always impact the temperature by using row covers and shade cloth, but being aware of these differences can help you select the right varieties and plant them at the right time.
If you want your raised bed to experience less fluctuations in temperature, you can place it against the south-facing side of a structure. This placement means the plants will still receive plenty of sun, but the structure will provide a bit of a buffer against changes in temperature.
Keep the Soil Moist, Not Wet
Well-draining soil prevents diseases like bottom rot.
One of the benefits of raised beds is the excellent drainage they provide. Even if you live in an area with heavy, compacted clay, you can still grow healthy crops with the help of raised beds. However, this excellent drainage has an impact on your watering schedule.
When you couple the excellent drainage of raised beds with their tendency to heat up faster on warm and sunny days, you’ll notice that the soil dries out more quickly than soil in the ground. Therefore, you should plan on watering your raised beds more often than you would an in-ground garden.
Most lettuce plants like their soil moist but not wet. Fortunately, a well-draining soil will prevent water from puddling and leading to diseases like bottom rot and drop. Your goal is to regularly check the soil moisture and irrigate so the soil never dries out completely. Since small seedlings have smaller root systems than larger plants, plan on watering smaller plants more frequently than larger plants. And don’t forget that elements like temperature, wind, and sunlight also impact how often you should water.
If you don’t travel much and love tending to your garden, hand watering with a watering can or hose is just fine. But if you want to automate things, you can set up a drip irrigation system and connect it to a timer. Just make sure to check the system every week or so for malfunctions, and adjust the run frequency based on soil moisture levels. Remember, the soil should be moist but not soaking wet!
Plant More than Once
Lettuce seeds won’t germinate in temperatures above 85°F.
One of the biggest mistakes I see home gardeners make is planting a crop once! Sure, you only need to plant a single tomato or cucumber plant to enjoy weeks of fresh produce, but that’s not the case with lettuce! If you plant five romaine seedlings at the same time in spring, you’ll have five mature heads that are ready to harvest at the same time. But if you never plant any more seedlings, that’s the only homegrown lettuce you’ll have to enjoy.
For a continuous supply of lettuce, plant new seeds or seedlings every two to three weeks. The practice of planting multiple rounds of a crop is known as succession planting, and it’s how farmers supply a continuous supply of lettuce or arugula throughout the growing season.
If you plan on direct sowing lettuce seeds in your garden, take note that these seeds won’t germinate at high temperatures. If the air is above 85°F (29°C), consider starting your seeds inside and then transplanting them into your garden.
Final Thoughts
Whether you want to grow dense heads of romaine or tender baby greens, raised beds provide an excellent growing environment. Remember to choose your varieties carefully, water well, and plant more than once for a continuous supply of homegrown lettuce.
