Plant deficiency guide
Iron Deficiency
Also called low iron, trace deficiency, interveinal chlorosis
New leaves at the tips come in pale, yellowing between green veins, and red plants fade to yellow-green.
TL;DR, Iron Deficiency
Iron is immobile, so a shortage shows on new growth, not old. The newest leaves emerge pale, yellowing between the veins while the veins stay green, and red plants are the loudest alarm, washing out to yellow-green. It usually means not enough trace or micro fertiliser, or dosing it at the wrong time relative to other nutrients. Add a trace or all-in-one fertiliser with iron. Reds also need strong light and CO2 to hold colour, so iron alone is not always the whole story.
What you see
The newest leaves come in pale, with yellowing between the veins while the veins themselves stay green. Red and orange plants lose their colour to a washed-out yellow-green, and tips can look bleached. Older leaves lower down usually stay fine, which is the giveaway that it is iron rather than nitrogen or magnesium.
What causes it
- Too little trace or iron dosing for the plant mass
- Iron precipitating out before plants can use it
- High light and CO2 driving demand past the trace supply
- A red-heavy layout that needs more iron than a green one
How to fix it
- Dose an all-in-one or a dedicated trace mix that contains iron.
- If you use dry salts, dose micros separately from macros, since they can react and drop out together.
- Make sure light and CO2 are strong enough, because reds will not hold colour on iron alone.
- Check the newest leaves after a week or two for fresh, evenly green growth.
Keep it from coming back
Dose trace and iron consistently, and dose more in a high-light or red-heavy tank. Splitting micro and macro dosing to different times helps the iron stay available.
Easy to confuse with
Other micronutrient shortages such as manganese look almost identical on new growth, which is why a complete trace mix is the usual fix rather than iron alone. Calcium also hits new leaves, but it twists and deforms them rather than yellowing between the veins.
Plants that show it first
Compare against a species you keep. These plants flag iron trouble early or clearly:
- Ludwigia 'Super Red' — Reds wash out to yellow-green first when iron or trace runs short, the classic indicator.
- Rotala Macrandra — A demanding red that pales fast without enough iron, light and CO2.
- Alternanthera Reineckii 'Mini' — Loses its pink-red underside to pale green when trace is low.
- Rotala 'H'ra' — Its orange-red tips fade first, an early iron and CO2 gauge.
- Red Tiger Lotus — New leaves come in pale rather than deep red when iron is short.
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Does dosing iron make plants red?
Iron helps reds show, but light and CO2 matter just as much. Iron on its own will not turn a plant red in a dim, low-CO2 tank.
Should I dose iron or a full trace mix?
A full trace mix is safer, because deficiencies in other micros look the same on new growth. Dedicated iron is a top-up, not a substitute for trace.
Why are only my new leaves affected?
Iron is immobile, so the plant cannot move it from old leaves to new ones. New growth shows the shortage first.