How to grow hydroponic lettuce

How To Grow Hydroponic Lettuce

  • Twitter
  • Facebook
  • Pinterest

Lettuce is the easiest vegetable to grow using hydroponics. If you’re just starting out with hydroponics, lettuce is the place to start. Hydroponic lettuce grows fast, doesn’t take up much space, and is easy to maintain.

Here’s everything you need to know about growing hydroponic lettuce!How to grow hydroponic lettuce

How To Germinate Lettuce Seeds

I prefer to use rapid rooter plugs to germinate lettuce seeds for my hydroponic garden. It’s best to sow a few seeds to increase the chances of getting a successful seedling and then thin them out, keeping the healthiest. It only takes a few days for lettuce seedlings to sprout.

After the seedlings rise above the starter cube, that’s when you pinch the heads off of the multiples, leaving the healthiest seedling. Make sure to pinch and not pull, or you may disrupt the root system of the seedling you’re going to keep.

What Hydroponic Systems Work Best For Growing Lettuce?

Lettuce can be grown in pretty much any of the different types of hydroponic systems. For my hydroponic lettuce gardens, I typically use ebb and flow as well as NFT hydroponic systems.

On a commercial level, the nutrient film technique (NFT) is the primary hydroponic method used to grow lettuce.

What Is The Best Temperature For Hydroponic Lettuce?

Lettuce is a cool-weather crop. It grows best at temperatures between 45 and 70 degrees, going from warmer during the day to cooler at night.

If your hydroponic lettuce gets above the 70-degree range it will begin to bolt, which means the plant begins transitioning into the flowering phase of its life cycle. Lettuce that has bolted has a bitter taste and is not very good for eating.

Spacing Requirements For Lettuce

Different varieties require different spacing. I found that in most of my gardens about 6-8 inches apart works well. Lettuce that forms a firm head should be placed about 12 inches apart to allow for fuller development.

Lettuce has shallow root systems so they don’t require a deep grow bed.

How Much Light For Hydroponic Lettuce Production?

Lettuce does not require a long duration or intense amount of light to grow. Hydroponic lettuce should get between 10 and 14 hours of light per day.

Since lettuce doesn’t need intense light, you have several lighting options. Many growing hydroponic lettuce opt to go with fluorescent lighting due to the minimal initial investment,  low power consumption, and low heat production.

The recommended pH level for hydroponic lettuce is 5.5-6.5 .

Hydroponic Lettuce Nutrient Requirements

One of the great things about growing lettuce is its nutrient requirements, which are pretty basic. Lettuce requires a n-p-k ratio geared towards vegetative growth. Since we don’t need lettuce to flower, you can use the same type of nutrients up until harvest.

It grows well with nutrients higher in nitrogen and phosphorus and has less of a need for potassium. I personally use Dyna-Gro Foliage Pro nutrients for growing my hydroponic lettuce. It’s a one-part nutrient solution that works perfectly for growing lettuce.

Days Until Lettuce Harvest

How many days it takes until you can harvest your lettuce depends on a couple of factors. First, it depends on what variety you’re growing. Loose leaf and bibb lettuce can take about 45-55 days, whereas Romain can take up to 85 days to harvest.

The second factor has to do with a simple preference of how much you want to harvest at a time. I like harvesting small amounts, letting them grow back, then harvesting them again. This is called the “cut and come again” method of lettuce harvesting.

In my 2 ft. x 3 ft. ebb and flow garage system above, I was able to have a salad at about 3 weeks. You cut from a couple of plants one day, another couple the next, spacing out and extending your harvest.

Below are some pictures of the hydroponic lettuce flood and drain system I had in my garage.

Hydroponic lettuce a couple of weeks old Hydroponic lettuce growing in garage ebb and flow system.
Hydroponic lettuce ready for harvest. Harvested hydroponic lettuce


I hope you have found this article on how to grow hydroponic lettuce helpful! If so, please take a second to show us some social media sharing love. I’ve also put together a pretty nifty infographic you can check out below.

How to grow hydroponic lettuce Infographic

4 Answers

  1. Jared Berger
    November 6, 2020 at 1:33 pm

    Hi Michael,
    I’m setting up an NFT system with plans to grow a few varieties of lettuce. I have 2 questions:
    – You stated in your article that lettuce likes a nutrient geared towards growing (rather than blooming) but likes more N and P but less K. I bought General Hydroponics MaxiGro 10-5-14; do you think it will still work, or is it too heavy on K?
    – Do you think there’s any benefit to putting the water pump on a timer, or should it run 24/7?
    Thanks for the information,
    J. Berger

Leave a Reply

Your email address will not be published.
Required fields are marked *