Can I use regular houseplant fertilizer?

No, regular fertilizer can cause algae blooms and may be toxic to fish. Always use specific aquatic plant fertilizer.

Does yellowing mean I have too much sun?

Usually not, as water horsetail loves full sun. It is much more likely to be a lack of nutrients.

Water horsetail: yellow leaves, causes and fixes

Check these first

Check that the roots are completely submerged in water.
Smell the water to see if it has a rotten odor.
Examine the stems for any signs of physical damage.

Likely causes

Nutrient deficiency
Most likely
How to tell: The stems turn a pale yellow while the plant looks generally weak. This happens when the water lacks enough minerals for growth.
What to do: Add a slow release aquatic plant fertilizer tablet into the soil or container. Use one tablet per gallon of water once every 2 to 3 months during the growing season.
Poor water quality
Possible
How to tell: Yellowing occurs alongside murky or foul smelling water. This indicates a buildup of waste or stagnant conditions.
What to do: Perform a partial water change by replacing 25 to 50 percent of the water. Ensure there is some water movement or aeration to keep the environment fresh.

Yellow leaves on other plants

Find out what's wrong with your water horsetail

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

It is normal for the oldest stems at the base to yellow and die back as the season ends. Worry if the new growth at the top is turning yellow.

Stopping it coming back

Keep the water clean and provide a balanced aquatic fertilizer during the spring and summer months.

Water horsetail: yellow leaves? Check yours with a photo

Every plant is a little different. Take a photo of your water horsetail and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

Get the app · Or check it from a photo now, free

Questions people ask

Can I use regular houseplant fertilizer?: No, regular fertilizer can cause algae blooms and may be toxic to fish. Always use specific aquatic plant fertilizer.
Does yellowing mean I have too much sun?: Usually not, as water horsetail loves full sun. It is much more likely to be a lack of nutrients.

Why are my water horsetail stems turning yellow?