Want to grow hydroponic lettuce at home? It’s an ideal plant for hydroponics, and it’s one of the easiest too. Lettuce grows quickly and needs very little extra care. Here’s the complete guide to growing hydroponic lettuce!
Hydroponic Lettuce: An Overview
Before we get into the guide, here’s a look at the main points about growing lettuce:
- Ready for harvest between 4-8 weeks (depending on variety)
- Ideal light- 10 to 14 hours daily
- pH- between 5.5-6.5
- Grows well with fluorescent lights (CFL or T5)
- Ideal for DWC, NFT, and ebb and flow systems
- Has a shallow root system
- Best temperature – approximately 66 degrees
- Temperature above 70-75 F ( 21-23.8 C) degrees may cause bolting
- Vegetative nutrients preferred
First, Pick Your Variety
There are plenty of types of lettuce to choose from. You will see tight head and loose head lettuce. Tight head lettuce grows in a bunch, with the typical ball shaped cabbage head. The most common is Iceberg lettuce although there are many others. Loose head lettuce grows with more individual (or loose) leaves. An advantage of loose head lettuce is you can pick what you want, and continuously harvest it. Remember, when you grow lettuce in hydroponic systems, you may choose a different variety than you would pick up in the supermarket.
Best loose lettuce varieties
- Oak leaf
- Red fire
- Green Ice
Best tight head lettuce varieties
- Summer crisp
Top Lettuce Choices
Lettuce does not need very intense light, and that’s why it is easy to use fluorescent grow lights. It’s not a very fussy crop either, and generally tolerates temperatures between 45 or 50 degrees to 70 degrees Fahrenheit (7.2/10 to 21 Celsius). Some varieties tolerate higher temperatures, although many will bolt if temperatures rise above 70 or 75 degrees Fahrenheit (21-23.8 Celsius). A slightly lower nighttime (lights out) temperature is best.
Lettuce does best with a slightly acidic pH- around 5.5 to 6.5. While it does not need much accommodation when it comes to nutrients, a formula designed for vegetative plants is best. Most varieties do best with 10 to 14 hours of light (under grow lights), so many growers use a 12/12 cycle (12 hours with light, 12 hours without).
The time until harvest depends mostly on which variety you select. While Buttercrisp or Bibb matures within four weeks or so, other varieties, like Iceberg, can take up to eight or nine weeks. Of course, if you want a variety you can keep harvesting while the crop keeps growing, loose lettuce varieties are best. Once they mature, you can take what you want (it’s advised to leave at least 40% of the crop to allow regrowth) and harvest the rest as needed.
Hydroponic lettuce grows best from fresh seeds. Unfortunately, lettuce is one of those crops where the seeds may not keep as well as others. Our best advice – use fresh lettuce seeds, no matter what variety you choose. At the very least, make sure you use seeds intended for this (the current) season.
How to Grow Hydroponic Lettuce (Indoors)
Variety selected? Check.
Hydroponic system ready? Check.
Basic research done? Check-ish, (but that’s why you’re here!).
Ready to grow lettuce in your hydroponic system? Check.
Germinate those seeds!
Let the sprouts grow
Transplant the lettuce
Grow to maturity
Special Considerations for Growing Lettuce Hydroponically
Lettuce is an easy going crop. You don’t have a whole lot to worry about. Unlike other plants to grow in hydroponics, lettuce is more or less vegetative, and doesn’t flower. The foliage (leaves) is the main crop. That makes figuring out nutrient solution easier. You can pretty much use a vegetative nutrient formula the whole way through until harvest. Just keep your EC between 0.8 and 1.2.
We recommend General Hydroponics MaxiGro formula
The best water to use is Reverse Osmosis filtered. We recommend the GrowoniX Reverse Osmosis System
Frequently Asked Questions
Can I eat bolted lettuce?
You can eat bolted lettuce. You may not like it, however. When lettuce bolts, it is still safe to eat, but it doesn’t taste particularly good. The leaves are bitter, and the more bolting happens, the more unappetizing they are. If bolting is just starting, you may be able to harvest some of the lettuce before the taste changes too much.
My lettuce bolted! What can I do with it?
There are plenty of things to do with bolted lettuce, even if you do not want it for your salad. For one, you can cut away the foliage and simply regrow your crop. Animal shelters often take donations like bolted lettuce, so call your local shelter to check. Or, you can use the cut plant for composting fertilizer for an outdoor garden. The other option is to simply allow the lettuce to flower and bloom and take the seeds once the plant matures.
Is growing lettuce hydroponically profitable?
A couple factors the ROI for hydroponic lettuce. First, the variety. Next, the scale of the system. While lettuce does grow quickly (especially when you grow hydroponically), to make a profit you have to have a larger system, preferably commercial grade. The variety is important too. While Iceberg lettuce gains higher profit in traditional agriculture, that is not the case in hydroponics. Some of the most profitable lettuce varieties in hydroponics include Romaine, Bibb, and Butterhead.