How Do You Grow Lettuce In Aquaponics?

You can grow lettuce in aquaponics through the three widely-known setups: media-based aquaponics, nutrient film technique, and deep water culture. To attain maximum plant growth, certain factors must be kept in mind. The lettuce variety, the water quality, and the companion fish, just to name a few.

Why grow lettuce in aquaponics?

When you have the time to visit aquaponics farms, you will likely find lettuce as one of their growing vegetables. This plant is one of the widely-grown crops in the world of aquaponics. Below are some popular reasons for this:

Lettuce is easy to grow.

The lettuce plant is one of the easiest to grow crops. They require minimal supervision from growers as long as the correct growing range is met, such as proper temperature and adequate water supply. Lettuce is a common crop in the list of aquaponics plants beginners can grow.

Lettuce grows fast.

Lettuce will definitely make it if you list down the fast-growing veggies on the market today. This plant type can reach maturity in about 30 days. However, you can harvest them as soon as the necessary size is reached. Other lettuce varieties need 6 to 8 weeks to achieve a harvestable size.

Lettuce has high water content.

Raw lettuce is said to contain 95% water. This means lettuce loves water and the aquaponics approach is ideal for this particular requirement.

Lettuce is a nutritious food.

Another valid reason why you should add lettuce to your aquaponics setup is that it offers numerous health benefits. Lettuce is high in vitamin K, which improves bone density. The vegetable is also high in vitamin A, which is essential for eye health. By taking vitamin A person's risk of cataracts is reduced.

Lettuce does not require much space.

The vegetable we are considering is a common choice for gardeners who are apartment dwellers. This selection is based on the fact that lettuce will not require large are for its growth and development. Some are even cultivated in small-sized containers. Such quality of the plant is perfect for your chosen aquaponics design.

What are the different varieties of lettuce?

  1. Crisphead: Crisphead lettuce, often known as iceberg lettuce, is a compact, spherical lettuce with overlapping leaves. The internal leaves of the plant are paler and sweeter, while the greener ones on the outside are pliable. These outer leaves are suitable for lettuce wraps. This lettuce variety is primarily grown in milder areas in the north. It requires a little more upkeep than looseleaf cultivars and has a distinct flavor and texture not seen in those types.
  2. Summer crisp: This kind of lettuce is known also as French crisp or Batavia. Lettuce from this variant survives summer heat better than most lettuce varieties. Summer Crisp plants are also slow to bolt and have a lower resistance to tipburn and rot than other varieties. From planting to harvest, most of the types require roughly 45 days.
  3. Butterhead: This kind of lettuce gets its name from its unique sweet buttery flavor. The big, ruffled outer leaves have a delicate texture, usually grown to full-size heads. Heat tolerance is slightly higher in butterheads. Nonetheless, they should be planted early or late in the spring, away from the hot summer sun. Plants should be spaced 10-12" apart, with 12" between rows.
  4. Romaine: Our favorite Caesar salad is made with this sort of lettuce. Its lengthy leaves are crunchy and crispy yet have a slightly bitter taste. Romaine lettuce is the most heat-tolerant and bolt-resistant of the varieties discussed here. Romaines, on the other hand, thrive in cold regions. Romaine lettuce takes 65-70 days to mature from seed to harvest.
  5. Looseleaf: Home growers usually choose looseleaf to grow in their gardens, and it is one of the easiest to maintain. Having them in your garden means you'll be able to enjoy mild, sweet greens. Looseleaf forms rosettes of leaves rather than compact heads. They also differ in appearance, with some seeming crinkled and others appearing ruffled. Looseleaf lettuce comes in various hues, including green, red, yellow, and purple.

Which variety is best for aquaponics?

The crisphead, summer crisp, butterhead, romaine, and looseleaf lettuces all work well in aquaponics. Although the cultivars may be grown in different types of climate, the lettuce varieties briefly discussed can thrive using the various aquaponics available to date.

What aquaponics method is best for lettuce?

The three widely-used methods for aquaponics are adequate to support lettuce's growth and development. Moreover, each of these fits whatever purpose the grower has in mind.

Media based aquaponics

Lettuce grows exceptionally well when placed in media-based aquaponics. One key distinction is that these plants' roots will not be immersed in water permanently. This lettuce-growing method entails constructing a grow bed into which seedlings are sown.

Those who grow lettuce for hobby's sake usually employ media-based aquaponics.

Nutrient film technique (NFT)

The NFT is another appropriate growing method for lettuce. In the Nutrient Film Technique, a thin film of water continuously flows through the pipe/gutter. Consequently, the water is always in contact with the root. Since the roots are exposed above the thin water film, the lettuce has constant access to nutrients and plenty of oxygen. For optimum growth, the nutrition solution must be continuously circulated in this system.

Deep water culture (DWC)

Another name for this aquaponics setup is the floating raft system or DWC. If you produce lettuce for commercial purposes, the deep water lettuce is perfect.

The raft method necessitates a constant supply of water. The raft is made from a piece of polystyrene or similar material that may float on water, thus the phrase "lettuce in rafts." Each lettuce seed is planted in a raft hole. One of the most popular solutions for this is Rockwool or foam sponges.

The lettuce plant's roots will be suspended in oxygenated water pumped from the growing portion to the fish tank and then returned to the lettuce growth area. This provides the roots with immediate access to all nutrients they require to develop healthy and robust.

What factors should I consider to grow lettuce in aquaponics?

Method of planting

Typically, lettuce in aquaponics is transplanted. Lettuce seeds are ready to transplant when the plants have two or three genuine leaves three weeks after being planted. To avoid stress during the transplanting period, you can provide a phosphorus supplement in the second or third week.

Here are some known steps of planting lettuce seeds for transplanting:

  1. Put 3 to 5 seeds in a starter media. This can be Rockwool cubes, peat pellets, or plugs.
  2. In a growth tray, plate, or bowl, add the cubes, pellets, or plugs where the seeds are planted. Afterward, water them, and place the container in the dark.
  3. For up to two weeks, mist the seeds or growing media. Do this step once a day.
  4. Following 10 to 15 days of placing the seeds in your media, these would have sprouted and are ready for transplanting.


Lettuce needs up to 18 hours of sunlight per day to thrive. If possible, place your system near a window where sun rays freely enter. This step may still be insufficient to provide enough light throughout the day. The remedy here is to use artificial grow lights that turn on at sunset.

For temperature, lettuce does well in air temperatures between 60 degrees Fahrenheit (16 degrees Celsius) and below 75 degrees Fahrenheit (24 degrees Celsius). It is even advisable to maintain the water temperature at roughly 70 degrees Fahrenheit (21 degrees Celsius).

pH range

Like other aquaponics crops, lettuce will require a particular pH range that will aid in its growth and development. This specific plant is comfortable to grow in water with a pH ranging between 5.8 - 6.2.

However, it is a reasonably hardy crop that can tolerate pH levels outside the recommended range. But of course, if the pH level is not maximized, the lettuce plant may not grow as large or taste as it should be.

It should be noted that, while the pH is somewhat flexible, higher levels of calcium in the water will benefit lettuce. During the height of summer, this can help prevent tip burn on their leaves.


Experienced growers plant one lettuce every 7 inches to get the best yield. This spacing will give any grower the most lettuce per square foot and encourage maximum growth without the plant competing for nutrients or blocking each other's light.

This spacing is also dependent on the type of lettuce used. For example, rocket lettuce takes up less room than the butterhead.

Companion fish

The lettuce is best partnered with tilapia, trout, sunfish, koi, carp, and bass. All of these aquatic animals fall within the parameters of temperature compatibility.

How long does it take to grow lettuce in aquaponics?

Most lettuce varieties reach harvestable size in about 30 days. On the other hand, harder and "head" lettuces may need 45 to 60 days.

Just remember that your specific aquaponic setup influences the plant's growth rate. Having said that, lettuce may grow two to three times faster than it would normally.


Lettuce is one of the easiest to manage aquaponics crops. For this reason, it has been a favorite choice in many aquaponics farms. If you aim to include this plant in your thriving garden, observe the pointers this article provides, and a profitable harvest is not impossible.

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