Nutrient indicator plants

[Justin Schaeffer]

While reading posts in aquarium forums, I've seen some discussion on using plants that show nutrient defficiency symptoms early on as indicators for addition of micronutrients into the system to optimize plant growth.

The on that stands out was mentioned that pennywort is very susceptible to iron deficiency. When the pennywort shows signs of deficiency it's time to add some chelated iron. This way the plants that you are growing for food get the nutrient top up before the show deficiency symptoms.

Does anyone use indicator plants like this in their aquaponics system? If so what plants are being used?

[Kerry McMahon]

I had just read in another post where Vlad mentioned that he uses an oregano plant as an early iron deficiency detector.  Got me thinking about what other plants are good detectors for other nutrients.  So glad you posted this, I look forward to seeing the replies.

[Michael Silberstein]

Tomatoes will curl when N is high.  indicating you need more plants or less fish

Kerry McMahon said:

I had just read in another post where Vlad mentioned that he uses an oregano plant as an early iron deficiency detector.  Got me thinking about what other plants are good detectors for other nutrients.  So glad you posted this, I look forward to seeing the replies.

[Justin Schaeffer]

If the tomatoes are showing signs of deficiency you are already loosing yield. There are plants that have need of higher concentrations of some nutrients that can tell you to fix the problem before the crop plants are affected. 

[Kerry McMahon]

Vlad referred to them as "coal mine canaries".  (For those that don't know the history of coal mining, miners would bring a canary into the mine with them because the canary was more sensitive to the toxic gases.  When the bird died, it was time to evacuate the mine.)  The oregano was the only one he mentioned in that post though.

[Jon Paul]

What a great idea!  I have not gotten that sophisticated yet, but i am leaning that different plant show different signs.  having a plant to tell you if something is lacking seems like it could work better than using all those test tubes.