Low Income Hydroponics System: Lettuce

The goal of this project was to develop as cost efficient a system as possible that allows the (relatively) quick production of vegetables on a limited budget. Most of the items required can be purchased on Amazon.com or from your local hardware or pet store.

I set a goal of $20 or less to build out this system without any special skills required.

Step 1: Component List & Prices

Components:
1 - 18 Qt Hefty Tub $5.49

1 - Lettuce Nutrients $0.68

6 - 2" Plastic Grow Pots $1.08

1 - Air Stone $2.77

1 - Air Pump $7.12

1 - 2 Feet of Air Tubing $0.40

1 - Check Valve $1.88

6 - Rockwool $0.48

Total Cost = $19.90

Step 2: Setup

The system setup is quite simple and only requires a drill with one 1/4 inch bit and one 2 inch hole saw bit.

Steps:

1. Trace the net pot upside down on the inside lid of the Hefty Container. You want to leave room between each pot so you can fit 6 total on the lid.
2. Use the 2 inch hole saw bit on your drill to drill out the 6 circles you just made on the lid.
3. Switch to the 1/4 inch bit and drill a hole in the lid in one corner where you will run your airline tubing out from.
4. Pick a very sunny window, or if you live in a warmer climate, a sunny outdoor location to place your system.
5. Use warm water and fill the box with 4 gallons.
6. Add in 5 tsp of the nutrient mix and mix well.
7. Put the air stone in the bottom of the Hefty box and run the air line in through the upside down top and into the air stone itself.
8. Place the lid on the bow upside down

9. Install the Check valve between the air line coming from the air stone and the air pump. The check valve should have a small arrow on it indication the direction of the air flow - make sure this arrow is pointing towards the air stone.

10. Insert the free end of the air line into the pump and plug in.

11. Push the rockwool down into the net pots so that they are sitting in the water some.
12. Add your seeds to the center of the rockwool once it has soaked up the water some - maybe 5-10 minutes
13. Sit back and watch - just make sure to keep the water level up so that the bottom of the pots remain in contact. Once you have a strong root system, they can easily pull the water up if it slips below a little

Step 3: Plant Seeds

Once you have the setup complete, simply plant your favorite seeds in the rockwool and sit back. I have been harvesting lettuce in 24-28 days...

Enjoy your inexpensive and healthy crop!

Step 4:

Comments

[KellyB231]

First, thank you for well written descriptions and figuring out something I can try without a lot of financial risk.

If I want to grow lettuce can I just keep clipping leaves off and let the plant grow more?

[PaleoDan]

Thank you.

Yes, as long as you pick a leaf lettuce to plant like Red Sails, you can pick leaves and it will continue to grow, I try not to pick too much from a single plant if I want this to work, maybe no more than a 3rd of the leaves at any one time. Then I let that plant go for a week or so to regain it's strength.

[tarique.sabah.7]

Where is Step 4 ?

[JerryA35]

How long from seed to harvest? How many heads can you grow at once? My wife spends about $12 per week on lettuce feeding her 9 tortoise's !!!

[PaleoDan]

28 days form seed to harvest was the best I have hit (I only have 1 Russian Tortoise) to feed. It seems to average about 30 days.

[Shharon]

Can you tell me how to mix the super plant food? Mine didn't come with any instructions on how much to put in how much water help

[PaleoDan]

I have not had to add in additional nutrients, I just top off the water when needed. After I harvest, I start from scratch again with a new batch mixed up.

[PaleoDan]

If you purchased the exact same Fertilizer that I did, you will use warm water with the following ratio:

4 Gallons of tap water

5 Tsp of Nutrient Mix

[Shharon]

And how often do i add more nutrients to the water? Thank you for your help, these are things I can't seem to find anywhere.

[febsky]

I wonder if I can use this as an aquaponic system

[PaleoDan]

Here are a few pictures of the "outside" system I setup during the summer to grow more lettuce. It is basically the same as the one featured above except it uses a 20 gallon long aquarium and a piece of green floral type foam to "float" the lettuce on the water surface. I spray painted the outside of three sides black to cut down on the algae growth and leave one side clear so I can see what is going on root wise. Something similar should work to try this out for Aquaponics. - Please post some pictures if you do this.

[PaleoDan]

I think you could but I would leave out the fertilizer then - the fish should provide that. I think you would need to start the fish first to allow some build up of "nutrients" and then you could add the seeds. You might want to leave one section open so it is easy to feed the fish

[Shharon]

I bought a12x12 led light for under $20. At what distance should the light be from the plants? And, do you keep them in the dark until they sprout? Never done this but am going to try. Thanks

[PaleoDan]

The lettuce seeds I used sprouted very fast, within a day or two so I am not sure that matters. Light will not hurt them so I think you can have it on from the beginning. As for how high to have it, that will need some experimenting. If your sprouts look like they are "reaching" for the light or growing too long and thin, your light is too high, if the light is too close, you can burn them. How many watts does the light put out? I would guess maybe 12 inches off the tops of the plants so raise it up as they grow. Also if you have it in a window, the natural light will help throughout the day and you can always spin the unit to make sure all the seedlings get an "equal" shot at the sun.

[aunt margie]

What is rockwool?

[PaleoDan]

Rockwool is made by melting a combination of rock and sand and then spinning the mixture to make fibers which are formed into different shapes and sizes.

[rjmah]

You don't mention using the check valve. It may not be required as long as the air pump is mounted higher than the water level.

[PaleoDan]

Great catch - I did use the Check Valve in the build but forgot to mention it in the steps. For how cheap they are, it is safer to always use one. I will update the steps - thank you

[JohnC430]

very nice, but u show it lighted with an LED lamp which costs $28 plus shipping. windows do not have sunlight for more than a couple of hours a day so one needs the lamp to get any kind of growth indoors.

this looks like click bait to me. why do people do this game? I don't know how the Instructables works. do u get something for every click that u get?

[PaleoDan]

JohnC430 - I have not heard of click bate before but if you think there was an intentional omission on the LED lighting, you are correct. This was a experiment to see how inexpensive I could build out the system. As I indicated to another comment, I have the LED lights working on another project. The other project is to see which LED light works the best and is the cheapest. I will publish or add that when I see the difference. I am also an Amazon Prime member so shipping if free for me.

There was no malice or trickery intended