# Planted Tanks > Plant Talk >  Star Grass not growing well

## juggler

My Star Grass was growing fine and lately become like this:


Any ideas? My light is about 4.5W/g. Tank condition: 2 dkH, ~ 6.8 - 7 pH. I add about 20ppm K, 5ppm Mg weekly and daily dose of trace elements. Substrate is cocopeat. Temp 27C.

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## hoppinghippo

koah fong: I don't follow such stringent fertilizing like you but my stargrass seem to flourish tho there are occasional melting leaves, but never had blackened leaves. I have about 3.5W/gal light and 4dkh and ph 6.4, temp don't know but should be 27 I think (got fan). do your stargrass still grow runners, and do they bubble? if so then at least the conditions in your tank are still ok for at least some of them. I wonder if it's cuz you are overfertilizing? that's why you get blackened leaves? I personally fert using JBL ferropol about 2/3 times a week, one capfull.maybe you could experiment and not fert for a week and see how it affects? and do you have substrate fert?

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## CK Yeo

Stargrass is very easily bruised. You have ottos in your tanks? Their rasping action on the leaves will cause it to become like that, especially if you have a smallish tank and have a few ottos. 
It is not a nutritional problem.

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## juggler

Thanks! Could be the Otos then. I also notice the SAE nibbling on the Rotola wallichi. But couldn't catch the bugger.  :Sad: 

I only have cocopeat in the base topped up with some gravel.

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## gchoo

> ----------------
> On 4/7/2002 9:58:12 AM 
> 
> Thanks! Could be the Otos then. I also notice the SAE nibbling on the Rotola wallichi. But couldn't catch the bugger. 
> 
> I only have cocopeat in the base topped up with some gravel.
> ----------------


You probably need to setup a trap to get the SAE

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## hoppinghippo

I have 10 ottos in my 72L tank and I don't have the same condition for my stargrass?

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## CK Yeo

YMMV.

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## juggler

It's been two months since I encountered the above problem. Check out the grass now!



What I did:
1) I stopped fertilising with Mg two months back. The growth improved somewhat. Seems that too much Mg is no good.
2) I washed the filter (which has not washed for more than 6 months) two weeks back. And over the first weekend, the growth seem to increase by a third! It seems there is excessive biological filteration causing some nutrients to be depleted quickly. In fact I noticed sudden spurt of growth in all other plants after the filter washing.

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## peterkoh

Hi Koah Fong,

That's great news !

Is star grass a creeper and how tall does it grow ? Hope it is not so dependent on temp. like hair grass. where can i buy it ? Thks.

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## juggler

Peter: The plants creeps sideways as well as grow upwards. You get a mountain-like effect after a few months. Got them from Gen-X @ Clementi. If you like, I can try spare some cuttings.

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## DEA

nice, kf
how tall is it growing?

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## hwchoy

KF, looks great! how do you trim it to get a bush? I am thinking of making a small bush against a corner, the rest of the tank to be hairgrass and blyxa.

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## loupgarou

I've tried star grass 4 times already.. given up... (notice they fall under the easy category in tropica catalogue . rofl)

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## juggler

> ----------------
> On 6/4/2002 7:19:20 PM 
> 
> KF, looks great! how do you trim it to get a bush? I am thinking of making a small bush against a corner, the rest of the tank to be hairgrass and blyxa.
> ----------------


I started with a few strands in the centre of the tank 4 months back. No trimming so far. It tends to grow sideways and upwards (about 6&amp;quot; so far). So I guess it is good to start at the centre or back of the tank to get a good effect.

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## Simon

koah fong, but wouldnt the center melt away from the lack of light?

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## juggler

> ----------------
> On 6/5/2002 9:31:09 AM 
> 
> koah fong, but wouldnt the center melt away from the lack of light?
> ----------------


Simon: So far the core of the bush seem OK because it is growing loosely. But I think the core may slowly lose leaves due to lack of light eventually. But you still get a bushy effect at the surface. I saw that effect at Gen-X.

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## YES

wow..very nice stargrass.. 
my stargrass also got the same problem u faced last two months.. not growing very well and my yamatoes like to nibble it  :Mad:  .. guess it time to wash my external filter also.. [: :Smile: ]

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## toshi

At a glance, classic signs of phosphate deficiency - try amping via KH2P04 and monitor for consistent nitrate availability. Heteranthera is a voracious grower and will burnout first &amp;amp; easily. Surround it with fast growers and a very competitive situation arises... 

Cheers,  :Smile:  

---
toshi 
http://Toshir0.tripod.com/

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## sherchoo

Toshi,

Welcome... long time no hear from you.....

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## cks

your comments on k2so4 is very interesting. how do i apply it in my aquarium . value your advise . :Razz:

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## toshi

I dose a pinch of KH2P04 at a time, in general every 2-3 days. You can do this and watch for results (near instant increase in pearling) in a suspected P-deficient setup, or grab a phosphate test kit and dose to 1ppm. 

In the initial photograph, I can just barely make out Glosso below - but it brings up another good hint for P shortage. Aside from literally using a phos test kit to check levels, one can infer from certain indicator plants that the macronutrient may be lacking. For me, these plants are -

a) Glossostigma: slower growth, leaves much smaller than usual. Healthy glosso should have relatively large, thick, sumptuous leaves. It should be an extremely fast, invasive grower that takes some maintenance to control and corral.

b) Eichornia diversifolia: same story as with Heteranthera; sudden, widespread blackening of leaves &amp;amp; stem. Roots and internodal rootlets may remain intact &amp;amp; white.

Well-lit phosphate-deficient setups will bubble quite vigorously following a dosing of P. A nitrate level that was previously static will subsequently plummet as plants pull down P and consume more N than during the previous P-deficient situation. Plant leaves, particularly those of stem plants, will grow in with more size, more quickly overall. 

Detectable phosphate and nitrate are important to maintain at all times in well-lit, C02 dosed systems imvho. Nitrate is a very important macro, but phosphate is as well. 

For some, simply feeding their fish a bit more heavily will produce acceptable results. Frozen bloodworms/brineshrimp/daphnia, and sinking shrimp-based pellets are particularly high in P, relative to flake products.

If you can't locate a source of phosphate monobasic, many terrestrial liquid-based plant supplements can be found in NPK formulations that emphasize P &amp;amp; K (along with misc. micronutrients).

Ebi no idaina saigo desu!  :Angel:  

---
toshi 
http://Toshir0.tripod.com/

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## cks

will there be any drastic effects if k2so4 is over dosed ?  :Razz:

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## juggler

Toshi: Interesting insight. Thanks!

I always thought N,P will always be in abundance (but never tested for them) since I usually overfeed my fish. So I only dosed K and the micro-nutrients.

But in my case, the Stargrass grew tremendously fast after I washed the filter. And I noticed an increased in bubbling. I also noticed the following in some other plants:
1) Blyxa japnoica - stopped dying at the growing shoots and could be making a comeback?
2) Glossostigma - noticed some fresh bigger leaves, making a comeback as well?
3) Echinodorus 'Oriental' - sent up two baby plants
3) Alternanthera reineckii - new shoots looking great - not as withered looking as before
4) Riccia - more pearling.

As I read before, plants prefer N in the form of NH4 (including NH3) rather than NO3. And my filter not being washed in more than 1/2 a year could hold too much nitrifying bacteria that converted the NH4 to NO3. So N sort of becomes a limiting nutrient in this case. After washing the filter, lesser nitrifying bacteria means more NH4 available for plant growth.

I have experienced this phenomena several times already. Anyone else noticed sudden plant growth after filter washing, especially when filter was not washed for a long time?

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## barmby

Guys,

Don you think overdose of P and N is very dangerous? 

I guess Toshi's theory is for high lighting and CO2 environment. Cos these will all be consume quickly in such an environment. 

4 Watts/gallon! Must be a high maintenance.  :Cool:

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## toshi

Juggler, 

The cleaning of filtration media is an interesting hypothesis but one I don't personally subscribe to for encouraging growth. Also, consider that other factors might be at play; are fish consuming more food; have you switched foods; are you keeping a larger animal load. Whether the filter cleaning notion has merit or not I can't say with certainty, but consider that if it is a helpful aid, it is temporary until you next clean the filter. Meanwhile, I imagine that most are striving for consistent, long-term results with a dosing system that is acknowledged via observation and testing via kits. 

Meanwhile consider:

a) 

There are many who think a functioning biofilter &amp;quot;competes&amp;quot; with aquatic plants for nitrogen in its ammonia/ium/nitrite form. Let's for a moment assume this is the case. How much nitrite/ammonia is mitigated by a functioning biofilter before plants can pull it down? Remember that water is circulating, but not in contact with biomedia all of the time. On the other hand, fish are excreting urea on a regular basis - and when lights are on, plants are taking the opportunity to photosynthesize. In other words, during the light cycle both plants and filter have access to N in its various forms.

Without having a firm idea as to how thoroughly you purged your biomedia, let's assume you rinsed it very well and perhaps destroyed a fair number of nitrifiers. In this case it's plausible that nitrite/ammonia/um were allowed to pervade the water column for a longer period of time, allowing for prolonged access by more of the plant life. Whether this is a plus/minus for fish/crustaceans is a separate issue, but my personal feeling is that biomedia should not be impacted to such a degree, as once marked spikes in nitrite/ammonia are allowed to occur in high-light systems, instances of green water increase. Biologically unstable, strongly-lit systems which are unbalanced as regards macronutrients, in combination with N spikes, are leading contenders for green water. This is why a good compliment of biomedia is important, even in heavily planted strongly-lit tanks that are presumably pulling down N before it has a chance to hit a proprietary filter.

b) 

If we are to assume that allowing for more nitrite/ammonia/um in the water column is in fact beneficial, how can we provide the compounds safely and conveniently? More frequent purging of biomedia is probably not efficient or problem-free. Lately a few people have been using terrestrial plant food (i.e. Schultz Plant Food, a 10-15-10 mixture @ 8.2% urea &amp;amp; 1.6 ammoniacal nitrogen) to experiment. In small doses it is safe and is broken down by the biofilter, while a small amount of the pre-nitrate N is theoretically pulled down by plants quickly. 

c)

I've read the same - plants are reported to prefer nitrite to nitrate insofar as N consumption. By the same token, I am not prepared to rely strongly on nitrite for plant health, because I know that very similar results can be had via much less toxic nitrate, and because a system that carries measurable quantities of nitrite is less stable. For those who keep fragile fish the issue of nitrite is probably more important, than for those with plant-only setups.

d) 

In the end, the discussion may be partially moot: we have to proceed from known quantities. In this case, you must eliminate doubt by first testing for nitrate; is it measurable? Then, test for phosphate - is that measurable. Many, many people supplement nitrate via KN03 on strongly-lit C02 supplemented systems with excellent results, in combination with small pulsings of P if necessary. 

These are not over-the-top dosings, but rather controlled, small doses to keep nitrate/phosphate at manageable levels. When micronutrients are available and ample K is provided, along with Ca/Mg, it is pretty tough to crash a system via careful, controlled n/p dosing.

Oishi!  :Smile:  

---
toshi
http://Toshir0.tripod.com/

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## cks

hi toshi,
thank you for your detailed description however do you think that an over dose will cause any harm ?

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## DEA

toshi

do you know why NPK are called macronutrients?
i've been scratching my head over this for quite a while
i initially thought it was because they were needed in bigger amounts (&amp;gt;1ppm)
but after browsing thru the net i just got more and more confused

and cks
any overdose can cause problems
what toshi is saying here is to dose in moderation with close monitoring

for me i prefer macromanagement of nutrients as opposed to micromanagement
i don't test for the individual ones, i just give them whatever's in the fert i buy, and i do regular water changes
works just as well for me

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## DEA

but if you're referring to K, i have had overdoses to the tune of 1~2 slops of 40K ppm flourish potassium each day for my defunct 2 feet tank and i didn't notice any thing wrong with the plants
if anything, the plants just flowered more robustly

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## cks

DEA, 
thanks :Wink:

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## peterkoh

Hi KF,

How often did you change your water and how much ? Did the cleaning of filter medium coincide with more than usual water changes ? Beautiful tank like those in Amano books have frequent water changes.

Thanks for the offer of stargrass. Not sure how can I get it from you. Will pm you. As for Gen-X, where is it ?

Thks.

peter

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