Hydroponic Lettuce Light Requirements

Last Updated on March 15, 2022 by Maria B.

You might have an interest in growing lettuce hydroponically and you are wondering what the light requirements are. This is why we have put together information on hydroponic lettuce light requirements for you.

One simple vegetable to grow with hydroponics is lettuce and it’s a perfect vegetable to start with especially for beginners. Lettuce plants grown in hydroponics are fast and easy to maintain. They can be grown all year round in a controlled environment. They don’t take much space and their growing requirements are very easy to meet.

Hydroponic Lettuce Growing Light Requirements
Hydroponic Lettuce Light Requiremen...
Hydroponic Lettuce Light Requirements

Lettuce is a minimal demanding plant when grown hydroponically. Even at that, certain care is still needed for their growing requirements and light is one of these requirements. So let’s look at some of the hydroponic lettuce light requirements.

Light Duration Requirement

The adequate light duration for lettuce is about 10 to 12 hours. Lettuce is a low light plant and it won’t do well in full sun. Full light from the sun can cause lettuce to go into the flowering phase (bolt) and turn bitter.

Light Duration Requirement


Lettuce does well in cooler temperatures. The high temperature will cause your lettuce plant to bolt or go into the flowering phase. When this happens, your lettuce plant will taste annoyingly bad. The appropriate temperature during the day should be from 65 to 70 degrees Fahrenheit.  When the temperature surpasses 75 degrees Fahrenheit, your lettuce plant will start to flower or bolt. Moderately low temperatures at night of around 60 to 65 degrees Fahrenheit are great for lettuce. During summer, lettuce does not grow that fast, but it does grow.

Grow light

Lettuce does not require much light. So for this reason, most growers go for fluorescent lighting. Fluorescent lighting does not cost much, power consumption is low, and heat production is minimal. It is just the right grow light match for your lettuce plant.

Other Growing Requirements For Lettuce

Let’s take a look at some other growing requirements:

  • Growing Media: you can make use of Rockwool cubes as your starters for your hydroponic systems. Rockwool has a naturally high pH. So if you are opting for Rockwool, make sure you balance your pH before you proceed to plant. Other options for growing media are coconut coir and peat moss.
  • pH Range: the appropriate adjusting pH range for lettuce is 5.5 to 6.0.


  • Nutrient Solutions: The nutrient solution for lettuce is very essential. This is because it majorly serves as the growing medium for your lettuce plant to grow. Lettuce does not demand too many nutrients, but its nitrogen demand is pretty high. The nutrient solution with an N-P-K ratio should be high in nitrogen, have a little phosphorous, and not so much potassium. The nutrient solution should be able to yield great production as well as preventing it from entering the flowering phase (i.e. bolting). Calcium is also an essential nutrient for lettuce varieties that are prone to tip burning. Thus, ensure you feed the nutrient solution with a good portion of calcium.

Types Of Low Light Lettuce Grown In Hydroponic

Below are the commonly grown types of hydroponic lettuces:

  • Butterhead Lettuce: butterhead lettuce is one popularly grown hydroponics lettuce that is a low light plant requirement. It consists of two types: Boston lettuce and Bibb lettuce.
  • Loose-leaf Lettuce: Loose-leaf lettuce is also minimal light lettuce. This type of lettuce does not usually form heads.
  • Romaine Lettuce: romaine lettuce is also a commonly grown lettuce. It is the major recipe for Caesar salad and its taste is a string and the texture is crispy. It is also a low light plant. Romaine lettuce has various varieties such as open heads and tighter heads.

Lettuce Growing Period

Lettuce grows short-term and fast. The duration in which the head of your lettuce plant ripens will depend on the variety. Usually, it takes about 3 weeks for the first edible leaf to emerge and about 45 to 85 days to get the full head harvest.

Final Note

Growing lettuce hydroponically is of great benefits and you can grow any varieties of lettuce in your hydroponics system. Lettuce has low light requirements and they are fast-growing. So be assured of ready available nutritious leafy green at your disposal.

Lettuce will take about 21 days to grow its edible leaves and 45 to 85 days for its full head to be ready for harvest. Its requirements are not too hard and it is one of the easiest plants to grow hydroponically.