Backyard Aquaponics
A place to discuss aquaponics

Today I did a partial water change to adjust the ph down and added iron chelate because my kale was showing indicators of iron lock out (yellowing between the veins). None of my other plants showed signs of deficiency. This got me thinking:

Are there other plants that are good indicators nutrient deficiency?

IE Tomato's might be a good plant for indicating a phosphorus deficiency because the leaves turn purple.

Ideally you want a plant that is really sensitive to a nutrient deficiency. Tomatoes might do the job but since they are often a primary crop, not so well.

Phosphorous can be tested for easily, and is not normally an issue unless you have a lot of fruiting plants in the system.

potassium is harder - I've not found one particular plant shows it first and most only really show when there is an acute rather than chronic deficiency. Would be handy to have a K indicator. Iron is pretty obvious if it is deficient.