5 Advantages To Hydroponic Gardening
Growing your own hydroponic vegetables is easier than you may think. It is also cost effective and one or two harvests from this simple, inexpensive floating raft hydroponic lettuce system will pay for the cost of initially setting it up.
There are five main advantages to hydroponic gardening.
- You can grow vegetables year round.
- The plants grow from two to four times faster than soil crops.
- There are no weeds to pull or to spray for.
- Soil-born pests and bacteria are eliminated.
- Hydroponics actually uses far less water than soil farming.
In colder climates, hydroponic gardens can be set up inside under lights to keep plants warm and growing in the winter. In tropical climates, plants can be grown indoors to rescue lettuce and other leafy crops from intense heat.
In mild climates, such as in the southern US during the winter and spring, and in the spring and summer up north, hydroponic systems can be set up outside, provided they are protected from heavy winds and rain.
This article explains how to make a simple, inexpensive hydroponic floating raft system for growing lettuce outside. The system could also be used indoors under grow lights. I have included photos for each major step to make the process as clear and quick as possible, so you can get growing right away.
Materials Needed With Prices
- 27 Gallon Heavy-Duty Black Tote (home improvement store) $11.98
- Six 3'' to 4'' Netcups (hydroponic store or online) 55cents each = $3.30
- One 1’x6’ ¾ inch thick Styrofoam insulation panel (home improvement store) $1.49
- HydroCorn/Hydroton or Leca Clay gravel (hydroponic store or online) $9.00 For 3lb bag
(You can substitute the more readily available Pearlite for Hydroton)
- Nutrient Solution (Miracle Grow Tomato Formula) $5.00
- Air Pump/Tubing/AirStones (discount store or aquarium/pet store) $23.
- Waterproof tape and black trash bags. $6.
- 9 pack of Lettuce Starts ($3.49) (Or you can start your own from seeds.)
Total initial cost is about $66. However, you will only use a fraction of the Miracle Grow and Hydroton/Leca Clay or Pearlite, and four black trash bags. The sixty-six dollars represents the most it would cost you to initially set this up, then you will have lots of medium, fertilizer, and a few other items left over that you can use for some time.
Considering that a bag of Romain lettuce in the grocery store costs at least $3.oo, this system will pay for itself after 3 1/2 harvests of the six lettuce heads it will grow. If you have the same results that I have had with this system, you can expect to grow that much lettuce every 2 1/2 months.
27 Gal Tote
Air Pump / Tube / Air Stones
Hydroton (Leca Clay) Growing Medium & Netcups
Hydroponic Nutrient Options
Position And Fill Tote
Position your 27 Gallon Heavy-Duty Tote where it will receive the most sunlight possible while being protected from heavy winds. If possible, protection from the rain is ideal as well. My floating raft hydroponic lettuce system is under the edge of my patio roof on the southern exposure of my house, which is perfect.
A black tote is best, because it blocks out light. Light tends to grow algae inside the water, and is best avoided. You can also spray-paint a clear tote, or wrap it in black plastic to block out light.
Be sure to have a nearby source of electricity, such as a grounded outdoor plug. You can also use an outdoor extension cord to supply power to the air pump. Always use caution when using electricity in the proximity of water, and follow the extension cable and air pump’s included safety instructions.
Once positioned, fill your tote with water. Leave about a four-inch space at the top of the container for the raft to float upon. This space will protect the raft from wind and movement.
Well water or rain water is best. If you must use city or county tap water, you may wish to test and correct the Ph of the water to get a Ph of between 6.4 and 6.7 for optimal results. Ph test kits and correction solutions are available at hydroponic or aquarium stores. However, rain water or well water, plus the fertilizer, will usually yield an acceptable Ph for growing leafy greens. You can grow hydroponic lettuce in treated city water as well, just not with stellar results.
It is important to know the volume of water in your tote so you can accurately mix the nutrient solution when the time comes. There are three ways to determine the volume of water in your tote.
One is to fill it to the rim, then measure the amount of water as you remove it to obtain your four inch space at the top. Then subtract this amount from the gallon size of the tote to calculate how many gallons are remaining.
A second way to determine the volume of water in your tote is to use a timer, and time how long it takes your running hose to fill a one gallon water or milk jug. (My hose takes eight seconds to do the job.) Then time how long it takes to fill your tote to the desired level. Divide the number of seconds it took to fill the tote by the number of seconds it took your hose to fill a gallon and you will know how many gallons are in your reservoir. In my case it took three minutes and ten seconds to fill my tote. 3X60+10=190 seconds. 190seconds divided by 8seconds per gallon = 23.75 gallons of water in my tote. I rounded this up to 24 gallons and called it a day.
The third way, if math is not your thing, is to simply fill the tote with a series of filled 5 gallon buckets and add up how many gallons it takes. The important part is to know how much water you end up with, so you can mix your fertilizer accordingly.
Positioned And Filled 27gal Tote
Water Level 4 Inches From Rim
Install Air Pump
Position your air pump close enough to run the air tubes into the bottom of your tank. The pump I bought has two outlets. Measure the hoses by unrolling the tubing and placing each where they can reach from the pump to the bottom of your filled tote. There is no critical placement, as long as the air stones end up basically at the bottom of the tank with enough hose to reach the pump.
It is best to mount the pump above the tank if possible. If not, be sure to create a drip loop in the tubing, so water can’t drip down the tube and into the pump. Most pumps include instructions for doing this. Follow the pump instructions and install your pump.
Be sure to soak the air stones in water for at least one hour before installing. This allows the tiny pockets inside the stone to fill with water and expel any dust that may have accumulated inside the tiny holes.
Hook up the pump, tubing, and air stones, then place air stones at the bottom of the tote. At this point you can turn the pump on. You may need to weigh the air stones down somehow. I ziptied mine to a clean piece of tile to hold them down.
Installed Air Pump
Add Nutrient Solution
Mix the appropriate amount of water-soluble plant food per the instructions included on the product you are using. There are a number of liquid fertilizers available. Miracle Grow Tomato Formula is the most readily available. Or you can visit a hydroponic shop and get something specifically made for growing hydro lettuce.
The best way to mix the nutrient solution is to remove some of the water from your tote by dipping a five-gallon bucket into the water. Then dissolve the recommended portion of plant food into the bucket to match the volume of gallons that you calculated your tote to contain. For my system that holds 24 gallons of water, I added 24 teaspoons of the water-soluble plant food that I use.
Stir the plant food into your bucket well, then pour the dissolved mixture back into your tote.
Adding Dissolved Nutrient Solution
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Build The Raft
Using a serrated knife, cut the Styrofoam panel to create two rafts that will sandwich on top of each other and make one panel that is 1 ½ inch thick. Use waterproof tape to tape together the two panels together. The standard width panels will fit inside the 27 gallon tote with about 1 inch of space around the perimeter.
If you have a larger piece if foam, you can trim it to fit perfectly inside the tote at the water level, and skip Step 6 (attaching the light-blocking baffle.)
Cut Holes For Netcups
Use the inverted netcups and position them on the raft as a guide. You want about two inches of space between each pot and the edge of the raft. Draw a circle using a felt pen around each pot position, then cut out the holes using a serrated knive. A bread knife works well.
Remember to cut about 1/8th of an inch inside the circles you have drawn, so the pot rim will sit around the edge of the hole.
Clean away the excess foam crumbs.
Trimmed Raft With Holes Cut
Attach Light-Blocking Baffle
Using waterproof tape strips, attach folded black plastic trash bags around the perimeter of your raft. This will allow the plastic material to drape over the edges of the filled tote, to keep light out of he water. Light fosters the growth of algae, so the darker the better.
Once your system is assembled, you can use a string to tie around the tote, and secure the plastic baffle from flapping around in the wind.
If you have a raft cut to the exact size of the container you are using at the water level, you can skip this step.
Light-Blocking Baffle Detail
Fill Netcups With Medium
Fill your netcups with Hydroton/Leca Clay or Pearlite medium and rinse thoroughly. This will remove any dust and stray particles from the medium so that your water stays as clean as possible.
Rinsing Medium in Netcups
Rinse your netcups filled with hydroton.
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Rinse Soil From Lettuce Starts
Prepare your lettuce starts by gently removing them from their container and rinsing all the soil away from the roots. This is a delicate procedure, but the soil will rinse away much easier than you may expect.
Rinse out as much dirt and debris as possible without damaging the roots.
Rinsing Soil From Roots
Fully Cleaned Lettuce Starts Roots
Plant lettuce in netcups
Hold the lettuce so that some of the roots are touching the bottom of your netcup. Carefully fill netcup with rinsed Hydroton or Pearlite to hold the plant upright. Do not pack the medium or you may damage the roots.
Lettuce Start In Hydroton Medium
Install Lettuce Raft And Netcups
Position your raft on the surface of the water in your tote. Be sure that the air hoses are not being pinched or bent by the raft. You should see bubbles sneaking into the holes in the raft. If there are not bubbles appearing in each hole, it is fine. This is just your indication that the air bubblers are still working, before your place the plants in the holes.
Gently insert each netcup into its hole and press the rim down to seal it in the raft.
Raft with baffle floating in tote
Completed System With Lettuce Growing
Hydroponic Lettuce Raft System
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That’s it. Now just watch your delicious lettuce grow. Lettuce grown in this way should grow at least twice as fast as soil grown lettuce in the same climate.
For example, the lettuce I grew in soil on the same patio was large enough to harvest leaves from in twenty days. The hydroponic lettuce was big enough to do the same thing in ten days. Results may vary, but properly executed hydroponic lettuce will always grow faster than its soil counterpart. The reason is that the plant does not have to expend energy to push roots through dense soil, and search for nutrients by straining the water it gathers from moist dirt.
Hydroponic vegetables require no week killers or weed pulling, no mulch, can be grown indoors or out, and mature faster that soil crops. They avoid soil-born bacteria, fungus, and pests. Also, growing vegetables hydroponically uses less water than traditional farming.
Growing hydroponic lettuce is easy, fun, inexpensive, and can be a delicious and nutritious hobby. Best wishes with your hydroponic lettuce adventures and happy growing.