Java moss - not so simple?

[Adron]

In a (to be fair, 9-year-old) video, Cory says Java moss is the easiest plant to grow, and a near-certain winner in beginner tanks.

I'm not a beginner by any stretch, but I've started to wonder if anyone has a bit more of a complicated history with the moss? Java used to be an absolute gangbusters success in my Fluval Flex 15-gallon tank; I never even bought it, it just snuck out of some driftwood I purchased and slowly bloomed into a gorgeous cloud of green in the background. 

I've since moved twice, and the moss has never been quite as happy. It's the same tank, but moved across town (Los Angeles) into conditions of VERY hard water (Altadena). Always at the far end of the charts on the test strip, around 150 KH and 180 GH. I also see a more-or-less steady pH of 7.5. I use Seachem Purigen in the filter and have a lot of other plants, as well as 4 nerites and 9 glass bloodfin tetras, all of which seem to do fine. But Java moss has just been much more sluggish and reluctant to pop off during this new chapter for my 15 gallons. None of the inhabitants are munching on it, and water parameters are healthy. 

Curious if anyone else has a complicated experience with java moss, and maybe if anyone suspects hardness has some effect? 

[JettsPapa]

When I first started keeping fish and plants Java moss did very well for me; well enough that I sold some.  Since then it has dwindled down until it's all gone.

I also have hard water, with pH higher than yours (8.2).  I suspect that's the issue, though why it did well at first makes me wonder if it's something else.

[Mary W.]

Agree it's finicky.  I have very soft water and mine wouldn't grow for the first year, but then when nitrate level in the tank got up to 20-40 (as fish multiplied) it took off.  Also, when the tank was newer and there was a lot of algae, that really seemed to inhibit the java moss.  

Do you have hornwort in your tank?  There used to be a lot in mine but I removed it because I didn't like it, and also read it can produce chemicals that inhibit other plants.  The java moss (and also other plants) took off after I removed the hornwort.  Could have been coincidence, but food for thought.

[Tait_007]

I know that ever since I had gotten a proper full spectrum led plant light for my aquarium my java moss won’t stop growing. Also a lot of trimming and “replanting” helped mine. I had trouble with it growing until I did a big trim and now about a month or two later I have doubled the amount of moss I have.

[JettsPapa]

On 4/18/2023 at 9:14 AM, Mary W. said:

Agree it's finicky.  I have very soft water and mine wouldn't grow for the first year, but then when nitrate level in the tank got up to 20-40 (as fish multiplied) it took off.  Also, when the tank was newer and there was a lot of algae, that really seemed to inhibit the java moss.  

Do you have hornwort in your tank?  There used to be a lot in mine but I removed it because I didn't like it, and also read it can produce chemicals that inhibit other plants.  The java moss (and also other plants) took off after I removed the hornwort.  Could have been coincidence, but food for thought.

I'm surprised to hear that.  I just sold a gallon Ziploc bag of it from my 20 gallon tank, and there's probably more than that left, and crypts are thriving in the same tank.

[Adron]

On 4/18/2023 at 7:14 AM, Mary W. said:

Agree it's finicky.  I have very soft water and mine wouldn't grow for the first year, but then when nitrate level in the tank got up to 20-40 (as fish multiplied) it took off.  Also, when the tank was newer and there was a lot of algae, that really seemed to inhibit the java moss.  

Do you have hornwort in your tank?  There used to be a lot in mine but I removed it because I didn't like it, and also read it can produce chemicals that inhibit other plants.  The java moss (and also other plants) took off after I removed the hornwort.  Could have been coincidence, but food for thought.

That's really interesting! Actually yes, I do have hornwort, but it's a pretty recent addition; only been in there 3 or so weeks, I think. The reluctance of the java moss goes back further than that, so I'm a bit skeptical hornwort is a factor, but I'm going to see what I can read about that subject. Thanks for sharing!

[nabokovfan87]

On 4/17/2023 at 10:31 AM, Adron said:

Curious if anyone else has a complicated experience with java moss, and maybe if anyone suspects hardness has some effect? 

I'm willing to bet it's temperature and light related.  When you move moss you should cut it to encourage growth. If you don't see any growth then consider turning up the lights.  I had a lot of success with moss, then my tank crashed and everything died off on me.  I was left with anubias, nothing else changed with the exception of CO2.  I was not diligent with ferts and it was a big mess of a situation. 

Years later, struggling with algae, moss has been the savior of the tank!  Give it good light, don't shade it out, and just be sure to keep it short to keep it growing.  1/4-1/2" lengths work well.
 

 

[PineSong]

I couldn’t keep Java moss alive in my current tank until I started supplementing with Flourish potassium to help my Java ferns that were tanking. I was perplexed about it dying off because in my past house (another state) it came in uninvited on a piece of dried out driftwood I bought from eBay and it grew like mad.
In my current tank I bought Java moss on purpose but it disappeared immediately and I actually thought that it was all dead. Months later I  was surprised to see that after a few weeks of adding the potassium, I had bushy areas of moss growing. 
My water is very hard and my tank is heavily planted so I thought maybe without the potassium it’s outcompeted whereas in my old tank it didn’t have as much competition. Photo below shows how much competition it has.

[nabokovfan87]

On 4/23/2023 at 6:39 PM, PineSong said:

Months later I  was surprised to see that after a few weeks of adding the potassium, I had bushy areas of moss growing. 

YES!!!!! That's awesome.  Beautiful little tuft of moss.