Lettuce Tub© is a carefree technique that allows you to grow hydroponically without electricity, pumps, or wicks of any kind. In fact, you don’t even have to change your reservoir or add nutrients.
Normal hydroponics techniques can grow lettuce without soil, but it requires a lot of moving parts such as: pumps, wicks, airstones …and the electricity to power them all.It’s as close to a completely “hands off” growing technique there is.
In a traditional hydroponics systems setup, you typically have your lettuce in a little pot with growing medium and you place it in a water reservoir. Then you fill the reservoir with nutrient solution up to a certain point. An airstone is needed to create bubbles that pop at the surface of the water, hitting your growing media and feeding your plant’s young root system.
Sustainable Living Center
Food production on the cool Oregon Coast is different from food production in hot humid Iowa. At the Center, we experiment with Permaculture techniques and technology to use existing material to solve our food production challenges of the coast. In addition, we strive to find low cost solutions and that anyone could do.
Sustainable Living Center Technique
Fill the tub full of nutrient rich water and cover with a lid. Drill nine (9) holes in the lid. Place lettuce seedlings in a special post called a net pots and place it in a hole in the lid such that the bottom of the pot is touching the water.
The Lettuce Tub©
Lettuce Tub© is a carefree technique that allows you to grow hydroponically without electricity, pumps, or wicks of any kind. In fact, you don’t even have to change your reservoir or add nutrients.It’s as close to a completely “hands off” growing technique there is.
Normal hydroponics techniques can grow lettuce without soil, but it requires a lot of moving parts such as: pumps, wicks, airstones …and the electricity to power them all.
In a traditional hydroponics systems setup, you typically have your lettuce in a little pot with growing medium and you place it in a water reservoir. Then you fill the reservoir with nutrient solution up to a certain point. An airstone is needed to create bubbles that pop at the surface of the water, hitting your growing media and feeding your plant’s young root system.
Sustainable Living Center
Food production on the cool Oregon Coast is different from food production in hot humid Iowa. At the Center, we experiment with Permaculture techniques and technology to use existing material to solve our food production challenges of the coast. In addition, we strive to find low cost solutions and that anyone could do are,
Sustainable Living Center’s Lettuce Tub©
Fill the tub full of nutrient rich water and cover with a lid. Drill nine (9) holes in the lid. Place lettuce seedlings in a special post called a net pots and place it in a hole in the lid such that the bottom of the pot is touching the water.
The seedling gets water from the tub, likes what it tastes and sends out more roots to get more of that nutrient rich water. The plant continues to grow, sends out more roots and consumes more water. An air gap is created between the surface of the water and the bottom of the lid. In this gap the plant sends out smaller horizontal roots to absorb oxygen.
These roots are called “oxygen roots”. If you were to fill the air gap with water it would drown the plant.
Technique based on Kratky Method
The inspiration for the Lettuce Tub© came from B.A. Kratky of the University of Hawaii and his discovery of the “oxygen roots”
If you actually fill your tub to cover the bottom two thirds of the net pots with water as the plant continues to grow, it will use water and the water level will decline – but your lettuce’s roots will have descended into the nutrient solution by that time.
If possible, use rain water. If not possible, draw tap water and let it sit for a day to let the Chlorine escape.
You will never refill your tub, your lettuce will keep using up water and exposing more and more of their root systems to the air, which will ensure your lettuce get enough oxygen to survive and thrive. When the tub is empty the lettuce is fully grown.
Steps to Build Lettuce Tub©
After the initial cost of the Kratky Tub©, each load of nutrients will
only cost $4,00 approximately $0.45/lettuce
.
Lettuce Tub© with Lettuce Starts
Cut a rock wool cube into three pieces. Place your seeding between the three quarters. Place rock wool with seeding into the Net Cups Mix the nutrients according to the instructions on package and pour into Tub. Fill your tub to cover the bottom two thirds of the net pots with nutrients. Put in shady location.
Lettuce Tub© with seeds
Cut the rock wool cube into three pieces. Place your seeds between the three quarters. Place rock wool with seeds into the Net Cups. Mix the nutrients according to the instructions on package and pour in Tub. Fill your tub to cover the bottom two thirds of the net pots with nutrients. Put in shady location.
Warning – You will never refill your Tub, until you start a new batch. Your lettuce will keep using up water and exposing more and more of their root systems to the air, which will ensure your lettuce get enough oxygen to survive and thrive. When the tub is empty the lettuce is fully grown.
But, if the tub is placed a location that receives rain. You will have to remove liquid to the level it had before the rain. If you do not, you can drown the lettuce.
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