Last Updated on November 12, 2022 by Guillermina
Are you interested in aquaponics and would like to know how to grow lettuce in the system? Then you must know what the best pH for lettuce in aquaponics is. If you don’t know what that pH is, keep reading this article and we will tell you all you need to know.
What Does Growing Lettuce In Aquaponics Mean?
Aquaponics is a system in which plants are grown in a soilless solution. They are grown in water and another growing medium is used for the plants to attach their roots to. Common grow media in aquaponics include Rockwool, vermiculite, clay pebbles, coco coir, grow rock, etc.
Fish are also kept in the water and provide waste which is turned into nutrients by the bacteria in the system, ensuring that the plants have a steady and healthy supply of food to keep growing.
Why Is Ph Important In Aquaponics?
Water is the life of an aquaponic system. Without it, you cannot grow anything in the system. To ensure that you get the best out of your aquaponics system, you need to maintain ideal water quality parameters for the fish and crops that you are culturing or growing.
The pH of an aquaponics system is one of the most important parameters that you need to monitor. If the pH of the system is off, a lot can and will go wrong. These include;
- Your fish dying, which will overload your filtration system, which will lead to
- Your filtration system not being able to efficiently filter pollutants from the water
- Your plants not growing well because they cannot absorb nutrients from the water, because
- Nutrients are not bioavailable.
The Best Ph For Lettuce In Aquaponics?
So what is the best pH for lettuce in aquaponics? So different types of plants have different pH preferences. Outside of their preferred pH ranges, they cannot absorb nutrients from the water. This means that the plants will not grow well and may even die.
Because pH also affects the efficiency of the filtration system, nutrients that are in the water will not get broken down into components that will be easily taken up by the plants. This may negatively affect the plants. For example, fish release nitrogenous waste in the form of ammonia. High levels of ammonia may be toxic to plants. The process of nitrification by the relevant bacteria oxidizes ammonia into nitrite and nitrate, which are more easily utilized by plants.
A pH range of six to seven is generally the most favorable for most plants. Some plants may prefer more acidic and some more basic pH ranges. For lettuce, a pH of 5.8 to 6.2 is the best for this plant to thrive. This is because the plant has a lower nutrient demand compared to other plants that are typically grown in aquaponic systems. It is important to maintain the right pH in your system, you can use a meter like this one to monitor it daily.
In conjunction with pH, there are other water quality parameters that are important to keep in particular ranges for efficient growth and production of your lettuce in an aquaponics system.
Other Important Water Quality Parameters For Efficient Growth Of Lettuce In Aquaponics.
It is very important to maintain water good water quality in an aquaponics system. Some of the other important parameters to monitor and control are;
- Dissolved oxygen (DO) – is important for keeping your fish healthy and happy, and efficient functioning of the filtration system. The DO level should be kept at least 5 mg/L. Use a DO meter to monitor the levels throughout the day.
- Temperature – is very important for the plants and fish in your system. If the temperature is too low, the fish in your system will stop feeding. This means that they will not be producing enough waste, which translates to nutrients for your plants. So even if the pH is right, if there are no nutrients for your lettuce to absorb, it will not grow well.
- Other parameters to monitor are total nitrogen and total alkalinity.
Although it may seem complicated to monitor the water chemistry of your aquaponics system, it can be easily done with the use of commercial test kits.
Why Grow Lettuce In Aquaponics?
Growing lettuce in aquaponics allows you to grow your own food for consumption. If you can upscale your operation, you can produce enough lettuce to even sell to your neighbors or supply your local supermarket or fruit and vegetable shop.
Because you can run your aquaponics in an indoor, controlled area such as a greenhouse, you can have year round production of this vegetable.
Growing lettuce in aquaponics also allows you to grow fish. These fish can be for consumption or for decorative purposes. Either way, it could be a fun way of growing your food and observing its interaction with other organisms. Recommended fish to pair up with lettuce in an aquaponics system are tilapia, trout, bass, sunfish, koi, carp, and goldfish. These are warmwater fish and will work well with your lettuce which also requires warm temperatures to thrive.
How Fast Does Lettuce Grow In Aquaponics?
Another added advantage of growing lettuce in an aquaponics system is the faster growth rates compared to growing it in the soil. You can get a crop of lettuce in as little as 4-5 weeks, compared to the 6-8 weeks it would take if you grew the same crop in the soil.
How Do You Maintain Ph In Aquaponics?
There are several methods you can use to regulate pH in your aquaponics system, depending on what you need to do;
- To raise the pH, you can use equal parts of calcium carbonate and potassium carbonate and add them to the water.
- To lower the pH, we recommend using acids such as nitric, muriatic, and phosphoric acids.
- Another option is to do a water change until you achieve the pH you want.
How Do You Harvest Lettuce From Aquaponics?
Notice when the leaves of your lettuce are large enough for consumption, and then harvest them. Simply harvest the outer parts of the lettuce and leave the rest of the leaves to grow bigger before you can harvest them.
When Should I Harvest My Aquaponic Lettuce?
Lettuce in aquaponics systems grows very fast and you can harvest it every two weeks. The best time to harvest is early in the morning when the leaves are still crisp and moist.
Take Home Message – The Best Ph For Lettuce In Aquaponics
Lettuce is an excellent crop for anyone who is starting out in aquaponics. This is because lettuce is such an easy vegetable to grow, and can even be grown in a newly built system. We hope the guidelines provided in this article will help you figure out everything else you need to know to get started on your journey to growing lettuce in an aquaponics system. We hope you now understand the importance of pH and know what the best pH for lettuce in aquaponics is, as well as the range to maintain your aquaponics system at for optimum growth.
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An aquaculture specialist and freelance writer. Passionate about anything sustainable living, such as growing your own food, and if you can do it in conjunction with fish farming, even better! I currently work as an aquaculture researcher where I can expand and share my knowledge and skills on aquaculture, crop farming and adding value to wastewater by using it to grow food products. I enjoy reading and learning as much as possible, and writing is another avenue for me to share the knowledge I gain with others. I want my writing to inspire people to try their hand at gardening, whether indoors or outdoors. You can even start by keeping a few houseplants indoors to help you gain a bit of confidence if you need to.