# Nutrients - emmersed vs. submerged



## Tom (25 Aug 2011)

Is there any difference in nutrient uptake between plants grown under or above water (assuming the same light intensity)?

I would assume that plants would take up nutrients faster out of water due to the higher CO2 content. Saying that, I can grow plants nicely out of water in nothing but a damp, nutrient-rich substrate. Under water, they seem so much more nutrient dependent. Is there any truth in these ramblings?

Tom


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## plantbrain (26 Aug 2011)

Yep, the growth rates are faster with emergent culture, hence one of the many reasons nurseries grow them this way.


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## Tom (26 Aug 2011)

Thanks Tom. Why is it that we need to dose extra in tanks even with a rich substrate, whereas they tend to be fine with just the substrate out of water?


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## Antoni (26 Aug 2011)

I know that the Be Bright series of ADA ferts, used for Wabi Kusa are very lean - a lot weaker of the standard line... Perhaps plants grown out of the water are not used to get nutrients through the foliage?!


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## ghostsword (28 Aug 2011)

With my emersed plants if I dose as much as I do on the tank the leaves burn. So I use osmocote, and old tank water.  it works great!


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## dw1305 (29 Aug 2011)

Hi all,


> With my emersed plants if I dose as much as I do on the tank the leaves burn. So I use osmocote, and old tank water.  it works great!


 Luis has made an important point, if you use a lot of fertilsers as liquid feeds for emergent plants you can get leaf "scorch" due to the hygroscopic effects of the salts, this doesn't happen in the tank because of the dilution effect of the much larger volume of water.

Despite this liquid feeding of the emersed leaves is very effective for certain nutrients, particularly nitrogen, potassium, iron and magnesium, where you get a very quick growth response. You have more options with emersed plants with regards to the combinations of fertilisers you can use, and whilst ammonium nitrate (NH3NO3) is likely to cause leaf scorch, urea (as an N source) or other low conductivity feeds wont. 

I mist all my house plants with a dilute liquid feed in the growing season, (including orchids, _Gardenia_, _Azalea indica_, ferns etc.), usually what ever liquid feed for tomatoes etc. is cheapest, and at about 1/3 the recommended dose. 

cheers Darrel


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## ghostsword (29 Aug 2011)

Thanks Darrel, good idea on the Tomato feed, so one can use it the same way for the tomatoes? Leaf burn is always something that plagued, as I am setting up a vivarium was worried about how to dose ferts.


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## dw1305 (31 Aug 2011)

Hi all,


> good idea on the Tomato feed, so one can use it the same way for the tomatoes?


 Yes, all plants can be foliar fed, in fact for plants without proper roots like epiphytic orchids or bromeliads it is the only way you can feed them artificially. You can also see this is the aquarium, where for the vast majority of plants it makes no difference whether the fertiliser addition is to the water column, or to the substrate. 



> Leaf burn is always something that plagued, as I am setting up a vivarium was worried about how to dose ferts.


 If the leaf burn is a ring around the edge and tip of the leaf? it is probably to do with water loss (in the less humid atmosphere), rather than fertiliser burn. 

cheers Darrel


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## ghostsword (31 Aug 2011)

Yep, it's  on the tip of the leaf. ok, so not much I can do with it then. 

Thanks for all the tips.


.


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## Morgan Freeman (3 Oct 2011)

This is the one thing that confused me when entering the planted tank world. With my terrariums I can't dose ferts because it will affect my dart frogs, but the plants grow healthy and seemingly without needing anything extra. Aquatic plants seem a lot pickier, probably why I struggled at first.


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## dw1305 (4 Oct 2011)

Hi all,


> With my terrariums I can't dose ferts because it will affect my dart frogs, but the plants grow healthy and seemingly without needing anything extra. Aquatic plants seem a lot pickier, probably why I struggled at first.


There are 2 main reasons, one is the obvious one about the availability of CO2, the other is to do with the plants.
When you plant a terrarium you use plants like _Anubias, Maranta, Anthurium, Fittonia_, Orchids, Bromeliads, Ferns, Mosses, Gesnerids etc. many of which are epiphytes and are adapted to conditions of low light in a  warm, humid, nutrient poor environment. Other plants like _Monstera, Epiphyllum, Philodendrons, Scindapsus, Peperomia, Ficus repens, F. benjamina_ etc may be suitable for larger terraria or drier conditions, but again are often naturally epiphytes.

If you plant an aquarium with aquatic plants that are adapted to low nutrient conditions, you don't need to add CO2 or much in the way of nutrients. However if you take plants from more nutrient rich conditions, particularly if they are really plants that grow as emergents in wet, open conditions (like _Hemianthus callichtroides_), you are going to need to provide more in the way of nutrients, light and additional CO2.

cheers Darrel


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## Morgan Freeman (4 Oct 2011)

Good point, I didn't consider the actual nutrient requirements of the different plants. Everything you've listed I use plus a few others.


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## plantbrain (5 Oct 2011)

Another way to address it is treat them like you might Bonsai Trees.

I often use richer clay soil vs the fracted cooked clay in the aquatic plants, vs the bonsai, but daily watering with dilute ferts is a good method. Another way to think about it: fertigation.

This is how all the house plants you get and see sold in shops are grown.

They do not use ANY soil, just bark and sand etc, then a fert solution is sprayed over the entire plant.
This reduces soil borne pest and vectors.

This way we do not ship pest everywhere.


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