Lettuce hydroponics is an excellent choice for your hydroponic greenhouse. They’re easy to grow, thrive in hydroponic conditions, are versatile in their use, and offer incredible nutritional bonuses. But how do you choose which to plant with so many varieties available? Here, we’ll discuss hydroponic lettuce, its benefits, and how to grow it. 

What Type of Lettuce Is Best for Hydroponics? 

Hydroponic lettuce offers a variety of types and flavors, suitable for nearly any palette. Since they’re delicious and versatile, they’re also perfect for your hydroponic farm. But with so many types of lettuce available, how do you pick just one (or even just a few)? Here are our suggestions for the best types of lettuce for hydroponic growers:

Hydroponic Butterhead Lettuce

Butterhead lettuce offers a velvety texture and a buttery taste. Because of their large, flexible leaves, these plants are an excellent choice for salads, sandwiches, and lettuce wraps. 

Hydroponic Oak Leaf Lettuce

With a sweet yet nutty flavor and a buttery, soft texture, oak leaf lettuce is always a favorite. Red and green varieties are frequent hydroponic favorites and quite attractive on a plate or sandwich.

Hydroponic Romaine Lettuce

Possibly the most popular type of lettuce today is romaine. It’s an incredibly versatile leaf with plenty of uses, and a hydroponic environment is a perfect setting to ward off contaminants. To learn more, read our guide to hydroponic romaine lettuce.

How to Grow Hydroponic Lettuce 

There’s no question that various varieties of lettuce are excellent choices for hydroponic growers. But if you’ve never grown hydroponic lettuce before, you should know a few things before you purchase lettuce seeds. 

Each lettuce variety will have its own needs, so it’s best to research the specific hydroponic seeds you’ve chosen to plant. The information here is general and may not pertain to every variety of hydroponic lettuce.

What Is the Best Temperature for Hydroponic Lettuce? 

Most lettuces thrive in cooler weather and typically grow outdoors in the cooler months of the spring or autumn. In general, lettuce should germinate in temperatures between 65° and 80°F. Once established, you can lower the temperature slightly, keeping it around 55°F at night and 75°F during the day. 

How Much Light Is Needed for Hydroponic Lettuce? 

Lettuce seedlings should get about 18 hours of sunlight or grow lights daily, followed by 6 hours of darkness. Once established, your hydroponic lettuce plants should get between 10 and 14 hours of light per day. 

Hydroponic Lettuce Nutrient Requirements 

Most hydroponic lettuces do best at a pH between 5.5 and 6.0. Ensure your plants get plenty of calcium to ward off burned or wilted leaves. Nitrogen levels will determine how tall your plants grow.  Also, keep on top of potassium, magnesium, and phosphorus levels to keep your plants healthy. In general, your NPK levels should be as follows:

• Nitrogen: keep the nitrogen level at approximately 5.

• Phosphorus: keep phosphorus levels between 15 and 20.

• Potassium: potassium levels should be in a range from 20 to 40.

How Long Does It Take Lettuce to Grow Hydroponically? 

One reason hydroponic lettuce is such a popular option is that most varieties grow quickly and can be harvested more than once. For most varieties, you can have fresh, healthy leaves ready to harvest within six to eight weeks. 

Harvesting Hydroponic Lettuce 

Harvest can be incredibly simple if you’re not concerned about regrowing your lettuce from the same root system. In fact, many growers remove the entire plant, root system and all, to prepare it for retail sale. For more immediate use, you might cut the whole head off just above the root, then dispose of the root system entirely. When harvesting this way, you may also want to dispose of some of the leaves near the plant’s base if they aren’t as crisp as the rest.

Can I Regrow Hydroponic Lettuce? 

Most lettuce varieties will regrow three to five times if harvested carefully. For most types, you’ll want to only cut the outer leaves each time you harvest, allowing the core and roots to remain and continue growing. 

How to Store Hydroponic Lettuce

The good news is that hydroponic lettuce, since it typically doesn’t have to travel long distances to get to the consumer, tends to last quite a bit longer than most soil-grown lettuces. This means you can store it various ways without worrying about it going bad. Store your hydroponic lettuce in a refrigerator, or set it on the kitchen counter with the roots in water. 

Health Benefits of Hydroponic Lettuce

Hydroponic lettuce has all the same health benefits as its soil-grown counterparts. It’s a good source of vitamin K, essential for bone strength. Since it’s up to 95% water, it can have a hydrating effect, and its vitamin A is good for the eyes. 

In addition to these benefits, hydroponic lettuce is far less likely to suffer contamination. Lettuces, in particular, are highly susceptible to dangers like e.coli. But most hydroponic systems protect against such pathogens by reducing the risk of contamination in the first place.

Why Is My Hydroponic Lettuce Dying?

There are a few problems that could harm your hydroponic lettuce crops. Here are some symptoms you may be seeing and their probable causes:

• Burned or wilted leaves: not enough calcium in your nutrient solution

• Premature bolting: temperatures in the greenhouse are too warm

• Limp leaves: too much or too little water, too much heat, too little light, or a fungal infection 

Frequently Asked Questions

Why is Hydroponic Lettuce Better Than Traditional Lettuce?

Hydroponic lettuce offers all the benefits of traditional, soil-grown lettuce. But it has the advantage of being protected from the contaminants that so often lead to food recalls. It is also more sustainable, using less water, no soil, and no chemical pesticides. 

Is Hydroponic Lettuce Healthy?

Yes! Hydroponically grown produce has the same nutritional benefits as its soil-grown counterparts and is typically fresher when it arrives to the consumer.

How Long Does Hydroponic Lettuce Last?

Hydroponic lettuce can last two to four weeks if harvested with the roots intact. 

Can Hydroponic Lettuce Have E. Coli?

Since hydroponic lettuce is grown in controlled environments, it’s hard to imagine a scenario where e.coli could be introduced.

Does Hydroponic Lettuce Need to Be Washed?

There are a few ways lettuce can be contaminated when it’s grown in a hydroponic environment, but it’s still best to wash vegetables before consuming them. 

What Lettuce Grows Best in Hydroponics?

Nearly any type of lettuce can grow well in a hydroponic environment, but some of the most popular varieties are romaine, red and green oak leaf, and butterleaf. 

Is Lettuce Easy to Grow in Hydroponics?

Lettuce is one of the most common hydroponic crops because it’s easy to grow and rapidly reaches maturity. That said, it’s still essential to understand the proper conditions for optimal growth.