What is it?
Often aquarists become aware of plant problems when the plant has been forced to use up its own internal reserves of chemicals and the leaves or stems change colour.
Here are a few common reasons and the cause.
Lack of Iron
Leaves become brittle, slightly glass like and normally look like they are rotting. They also look slightly less green and take on a more yellow appearance - add a source of iron in powder or bottle form.
Lack of Nitrogen
Leaves become yellow and older leaves die off. Sometimes leaves have a slightly reddish appearance and growth is slow - add a source of nitrate in powder or bottle form.
Lack of Phosphorus
Often quite similar signs to lack of nitrogen but look out for stunted growth and leaves becoming darker than normal. Root growth will also be under-developed - add a source of phosphate in powder or bottle form.
Lack of Potassium
Pinholes in leaves which slowly become larger over time. Leaves begin to curl, become yellow from edge inwards and also lose resistance to disease - add a source of potassium in powder or bottle form.
Lack of Calcium
Unusual leaf shapes, which are slightly bent or twisted. Leaves are often yellow on the edges – treat with additives to increase General Hardness.
Lack of Boron
Similar problems to calcium deficiencies – but also stems are delicate and new shoots appear dead - add trace elements.
Lack of Magnesium
Leaves become yellow all over. But may have green veins; they may also develop brown spots. If your plants are short of magnesium, they will be unable to absorb iron - add trace elements.
Lack of C02
Plants grow slowly and remain small. Leaves may droop. Calcium deposits on leaves and a pH rise – increase C02 or add a liquid Carbon source and minimise surface agitation.
Lack of Light
Plants are weak, spindly and leaves are small. The distance between leaves increases and plants become bushy closest to the light. Lower sections eventually become bare – add more lighting or increase the strength of lighting. Make sure stem plants are not planted too closely together.
Brown spots with holes
Likely to be be snail damage.
Centre of leaves rot away
The areas in between veins get thinner and eventually rot away leaving the edges mostly intact. This is usually seen with Echinodorus Swords. See Amazon Sword Melt.
Edges of leaves rot
- Other nutrients aquatic plants require - see Plant nutrients
- Thanks to Aqua Essentials for permission to reproduce this.
- Common Aquatic Plant Deficiency Diagram by Zapins. Excellent picture of common problems.