What Plants Can I Use for Hydroponics?

Grow any plant in hydroponics, if pH and TDS is right

Tim Gutsche 23.07.2021

If you are starting with hydroponics, you might wonder: “What plants can I grow in Hydroponics”, and even if you had already a successful hydroponic system, you also might wonder, What else can be grown in a hydroponic system?. Well to answer that question right away: You can grow essentially any plant in a hydroponic system, there might be some special techniques necessary to grow some plants but in general, any plant can be grown.

What plants need to grow

In order for plants to grow anywhere regardless of being a hydroponic or soil-based system is that the plant gets enough nutrients and water. In a soil based environment, the soil itself contains nutrients and stores the water poured into it. The plants use their roots to extract the nutrients from the soil.

pH and TSD, the vital metrics

In a hydroponic system, the nutrients are not contained in soil, because there is no soil, also it’s typically not ingrained in the growth medium. The plants extract the nutrients from the nutrient solution. In order to do so, the nutrient solution must contain enough nutrients, which is measured using a TDS Meter and the nutrient solution needs to have a suitable pH value in order for the nutrients being available for the plant to extract. Even if there are a lot of nutrients in the solution, with the wrong pH value they are not useful for your plants. So in essence if you manage the right TDS and pH values for the nutrient solution you can grow any plant in a hydroponic system. One easy way of finding out those vital values for you system is our Hydroplanner, it is a dictionary of plants and their favourite pH and TDS values. It also helps you to find matching plants, because within one system you can only have one pH and one TDS value, you must find plants which are compatible in terms of pH values. Use the Hydroplanner to plan your system and derive the right pH and TDS values.

Learn more about pH here

Match the system to the plant

Apart from the pH and TDS value there is another determining factor: it is important to choose the right crops for your system … or put differently, choose the right system for your plants. Some plants grow better with in some systems, and some system should be prefered to grow certain plants. So for the example a NFT-System works best with fast growing plants which only have shallow roots. The plants mostly hang their roots in the nutrient solution and there might not be enough support for heavy plants like fruits or vegetables. Of course you could build additional supporting elements which help plants to stabilize. However you could also choose for instance a wick or ebb-flow system which has more growth medium, and can thus support havier plants or plants with more roots like fruits or vegetables. Also vegetables with tap roots might be more suitable to a system different than NFT, because their need for vast root space. Regardless of the system though it’s important to manage the correct pH and TDS values.

Let’s get started

Lastly, to get started with hydroponics, there are some easy crops you can start with which work in any system. Those are lettuce, spinach, mint and basil.

If we look at those four examples from the hydroplanner, we will see the requirements for those plants, also let’s analyze the final system settings you would need in order to grow those four plants.

Lettuce

Lettuce in the Hydroplanner

Lettuce in the Hydroplanner

As you can see the lettuce has prefers a pH value of 5.5 - 6.5 to extract the nutrients properly. Moreover it only needs a TDS value of above 560. This is a relativ low value, but this is reasonable given the fact lettuce does not need a lot of nutrients for developing fruits or vegetable. Lettuce also grows quickly and has only shallow roots, therefore it’s perfect for a NFT-System where not much growth area for plants are given.

Spinach

Spinach in the Hydroplanner

Spinach in the Hydroplanner

Another good start plant is spinach. The pH requirements are comparable to those of lettuce. It prefers a pH value of 5.5 - 6.5. As you can see the TDS intake is higher than that of lettuce, it is around twice as high with 1260 - 1610. But given the comparable pH values you could easily grow both plants in one system. Also because spinach has rather shallow roots and grows quickly, you could use a NFT-System for growing it.

Mint

Mint in the Hydroplanner

Mint in the Hydroplanner

The mint plant is especially good for beginners, because it grows really fast and sometimes spreads over the whole system, there’s hardly anything you can do wrong with this plant, if you get the pH and TDS right. As you can see, mint needs a pH value of around 5.5 - 6 and needs also more nutrients than spinach with a TDS of 1260 - 1610.

Basil

Basil in the Hydroplanner

Basil in the Hydroplanner

Lastly, basil also grows fast and could be a good addition for your first system. With a pH value of 5.5 - 6.5 it is comparable to the other 3 plants and also with the TDS preferences of 700 - 1120 is comparable to the other plants. Even if basil grows sometimes pretty high, it’s still suitable for a NFT-System but can of course also planted in other systems like ebb-flow or wick system.

Growing all spinach, lettuce, mint and basil together

The Hydroplanner calculcates the perfect pH and TDS values for our system

The Hydroplanner calculcates the perfect pH and TDS values for our system

If you use now the Hydroplanner and add all four of the above plants to a system, the planner will calculate the resulting values for pH and TSD. In this case the results show, that in order to grow those four plants, aim for a pH value of 5.75 and put at least 1400 ppm of nutrients into the solution. It’s very simple, also the planner will automatically highlight other compatible plants while disabling incompatible plants. It helps you to figure out what can be grown hydroponically within one system.

Conclusion

Here is what we have learned in this article:

  1. Any plant can be grown hydroponically
  2. Plants need nutrients, while soil-based environment offer nutrients via soil, in hydroponics nutrients are added to the nutrient solution
  3. in order for plants to extract the nutrients a nutrient solution needs a certain pH value.
  4. There a two vital metrics for plants within hydroponics systems: pH and TDS
  5. However every plant can be grown hydroponically it might be necessary to match the plant to the right hydroponics system. Like shallow rooted, fast growing plants within NFT-Systems
  6. Use the Hydroplanner to find out suitable pH and TDS values for your system and your plants
  7. If you want to start growing, you can start with some easy to grow plants like lettuce, spinach, mint and basil