DWCL have found that the crops that grow the best using Nutrient Film Technique (NFT) and/or Deep Water Culture (DWC) are the more commercial aquaponics plants and vegetables including strawberries, melons, lettuce, tomatoes, cucumbers, and many different types of herbs.
This does not mean that they do not get root rot. Almost every type of crop can occasionally get root rot using these techniques, but you can significantly decrease the likelihood of that happening by simply trimming their roots every 4-7 days as necessary.
As you may already know, the biggest reason why root rot occurs is because the entire length of the plants roots are submerged in water. Many people have found that if root rot is a big problem for them, that supporting the plants with chicken wire, with gravel or some other type of aggregate can help.
I like to use chicken wire and make sure that an 1/8 or 1/4 inch of the roots are not submerged if I am having a problem, but usually that doesn’t happen if I just keep the roots shorter, and/or cut the roots back to the healthier portion of the root if it does happen. If only a portion of the roots are experiencing rot, I will just remove the entire length of those affected roots to keep it from spreading.
In fact, my first really successful aquaponics system using NFT was for tomatoes, so I had a lot of crops that did not do so well before that, but I didn’t really understand WHY. I was not cutting back their roots
when they got longer – heck, I wasn’t even looking at the roots – and once I understood that this was the major reason for them developing root rot in the first place, I simply examined and trimmed the roots if necessary every 4 to 7 days. I just imagine that the plants are in a small pot, and trim their roots to the length that they would be in a small container.
Take Home Message to Stop Root Rot
After I realized that you can stop the root rot by trimming, I never lost many plants after that, especially because of simple neglect. By the time you realize that there is a problem such as root rot by simply looking at the plant’s leaves, in many cases it is too late. Pay attention to the roots, and you can keep the rot from spreading and getting worse.
The reason you will not find a list of plants that are not specifically suitable for NFT or DWC is because – You can make almost any crop suitable for these methods – depending on how much you are willing to watch and trim any roots that tend to get long fast.
I would suggest using plants that have a “compact” nature or root structure – so any plants that you probably know about that grow well in a container or a pot (like raising aquaponic tomatoes) are the types of plants that will do best, and will need the least amount of root trimming. This also usually means that their root
structure is typically pretty small (that is why they grow well in pots and containers), and does not grow to be several feet long. Again, this will save you the time of having to trim the roots for crops with longer
root structures that grow quickly.