# Fertilizing floating plants



## devakalpa (Jun 21, 2011)

Hello all,

Great site! :hail:

I am planning to have some Water Lettuce, Amazon Frogbit and Hyrdrocotyle leucocephala (left floating, at most tied to driftwood) in a 24 gallon softwater tank. The will be under natural indirect sunlight. Currently I have Anubias coffeefolia, common Java Fern tied to driftwood and Duckweed and they are doing well and sprouting new leaves. TDS 88 ppm, KH 3 German degrees, temp 30 C (India ), pH 6.8 (should drift lower with Indian Almond leaves in tank). No CO2 supplementation. 

I was searching the net but did not come across any specific fertilising regimen for floating plants exclusively. Should I be supplementing N, P, K with traces and Iron in amounts necessary for low light tanks? If I have NO3 values at 5-10 ppm, do I need to supplement N? Or would partial water changes with a dose of Flourish comprehensive for the volume be sufficient?

I am not looking for spectacular growth, I am ok with slo-mo turnover but a healthy sustainability. 

Many thanks in advance.

Regards
Dev


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## illustrator (Jul 18, 2010)

I don't know about specific fertilizers and values, but they can take up fluid aquarium plant fertilizer just like any other plant. I would fine-tune it on their appearance: a bit yellowish leaves mean put a bit more fertilizer in. 

But then again, I am "old-school" and some of the expert-growers here will probably think that this is a very primitive aproach ...

I have seen water lettuce growing in open water enriched with waste from a sewer: leaves of 40-60 cm long (so rosettes up to 80 cm diameter). Growth so thick that some plants are pushed onto the shore. Oxygen depletion and rotting leaves underneath (smells like sulphur, lots of dead fish and crayfish). I never saw them florish better, but I would also never attempt to re-create this in an aquarium. All aquarium-specimens I have seen of this plant are very stunted in comparison.


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## devakalpa (Jun 21, 2011)

thanks illustrator.

I am old school myself. Living in a big city in a developing country allows me glimpses of water lettuce growing in all its glory in similar places. And water hyacinth and duckweed as well. Guess I shall go with your 'let the plant tell me whats right or wrong' approach.


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## Yo-han (Oct 15, 2010)

They need everything an aquatic plant needs but no CO2. SO NPK+traces


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## serenityfate1 (Sep 4, 2014)

Floaters dont really need to be cared for, they take up excess nutrients in the water


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## TropTrea (Jan 10, 2014)

serenityfate1 said:


> Floaters don't really need to be cared for, they take up excess nutrients in the water


This is only true if there are sufficient nutrients in the water column. Dependent on the fauna load and your feeding practices there may be enough but in a tank with a minimum of fauna they will eventually use up everything in the tank and begin to starve.

I have several tanks that are set up as breeder tanks for live bearers and they are filled with various floating plants for the babies to hid in. I usually end up thinning the plants every other week at which time I add a commercial fertilizer with high level of cleated iron. I also do 20% water changes in these tanks every 3rd day and without the iron dosing will see a change in the plants after a few weeks.


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