Najas guadelupensis lighting?

[davemonkey]

I'm tryig out Najas guadelupensis and I know I'm not the only person to ever grow it...I've seen it mentioned "here and there" before but I can't remember where. Has anyone here grown it, and under what lighting conditions?

It's a full sun plant in the real world, so I understand that it needs fairly bright light, but so are several other plants that I am able to grow well in moderate lighting. It's doing well with what I've got, but it will not stay rooted. The tops, from the tip to just at the substrate look great. The bottoms of the stems keep rotting at the substrate and the roots are frail...and in the wild it is a rooted plant with very sturdy roots. So has anyone grown these before and kept them rooted?

[TexSun]

I haven't grown these, but a couple questions come to mind. What type of substrate are you using? Also, how are you planting these (method)?

Looking at Google images, they appear to have a very thin stem. This could be easily damaged in planting?

[davemonkey]

I have some AquaSoil (ADA) which is pretty old, but still holds together. The stems are definitely thin and easy to break. I've been pretty careful with them, but I'm sure I have damaged a few. But even still, the roots grow fast enough that they should anchor them down quickly...but these roots are growing quite frail and whispy...not the thick turgid roots they have in the outdoors.

I just trimmed them and replanted the tops and added a bulb to see if that makes a difference. I really think it is the light. Chara seemed to do the same for me (not planted, just as a floater). Outdoors it is a robust bunching plant, and in the tank it was rather whispy and thin.

Ironically, Widgeon grass (Ruppia maritima) is doing great for me, just a little slower growing with longer leaf blades. But the roots and plant structure overall are similar to what it is in full sun.

[Totenkampf]

mine is growing well under moderate light as a floater. it got invasive under high light. i have the same problems with it rooting although it does seem to drop long whispy roots. maybe it requires a strong current in order ot grow robust stems and roots? i havent seen it in nature, but guessing by its specific name it is a river plant? i was thinking about buying some mineral wool from the hydroponics store over the weekend for plants like this but i got distracted and forgot to grab it.

i can tell you that is definately does NOT like excel / glut.

[TexSun]

mine is growing well under moderate light as a floater. it got invasive under high light. i have the same problems with it rooting although it does seem to drop long whispy roots. maybe it requires a strong current in order ot grow robust stems and roots? i havent seen it in nature, but guessing by its specific name it is a river plant? i was thinking about buying some mineral wool from the hydroponics store over the weekend for plants like this but i got distracted and forgot to grab it.

i can tell you that is definately does NOT like excel / glut.

What does the mineral wool do?

[Totenkampf]

its the same thing that potted aquarium plants are grown in. it is a growing medium that will sink and it doesnt affect pH or hardness much if any. it is pretty much used the same as wabu-kasi are now only you can get a whole package of the little 1" squares for about 12 bucks. you will also hear it called rockwool.

[makatak123]

They are SUPER easy to grow! I use 2x15 watt bulbs that I buy at petsmart and it grows like a weed!

[troy tucker]

I don't do a thing but trim mine. the lite is the stock lite on the tank. 13w I think. High flow will make it have a much stronger stem and root...but it will also brake stems of and they will float around the tank....

[davemonkey]

Interesting info guys...thanks!

@Totenkampf, when you say it got invasive under high light, do you mean as a flaoter, or planted?

I don't think it is so much the current as it is the light. Where I found it there was zero flow...it was a marsh. Of course, as I tyope this, something else comes to mind. There may be some moderate salinity there, as the site is a natural brackish marsh that has been leveed up and flooded with fresh water. So, maybe it needs a touch of salt? I have read that it isn't so much a brackish plant, as it is a fresh plant that can tolerate brackish conditions. However, teh chara spp I found with it, I also found in a very fresh site...very robust, in direct sun (and no flow again). In my tank it was whimpy. So I am leaning toward lighting.

Anyway, while I play with lighting on my tank, here are a couple pics for those who don't know what plant we're talking about...along with pics of the Ruppia that is doing really well.

Najas guadelupensis:




Ruppia...with detail: (it's the one in the very background...long needle-thin leaves)

[Totenkampf]

i have had it floating and also anchored it to DW with twine, either way it tends to form a mass like loosely packed java moss. i had some stored outside in a mosquito larvae 10 gallon tank and within a couple weeks it completely choked that tank lol. my sisters red eared slider loves the stuff tho.

[davemonkey]

Just to update, the high light has worked in keeping the plant rooted and looking healthy and turgid. They also get some nice coloration at the tips. I put 2 fish-need-it t5ho fixtures on the tank, each with 2 bulbs, and sitting 4" above the tank.

Now before anyone freaks out about how much light that is supposed to be, consider two things, the fish-need-it balasts are not a true "HO" balast. they barely put out more than a normal light balast. Also, the reflectors are kinda crappy, despite the fact that each bulb gets its own. So, using PAR (photosynthetic absorbtion ratio) instad of WPG (watts per gallon), I have somewhere in the moderate-high to low-end-of-high range of light intensity.

(For more info on PAR vs. WPG, read this thread on TPT: http://www.plantedtank.net/forums/sh...d.php?t=184368 )

Anyway, the summary is this: strong lighting will keep guppy grass rooted and colorful. :)

[davemonkey]

Forgot to put the specs on my lighting. Going by the chart I used, each fixture gives me a PAR rating of about 43, so about 86 total. According to another thread on TPT, and I quote "Samamorgan":

PAR Values(Source) - Thanks Gnomecatcher for the suggestion!
Values between 10-30 are considered low light.
Values between 30-80 are considered medium light.
Values between 80-120 are considered high light.
Keep in mind that these values are what is currently accepted by the community as accurate, and aren't set in stone.

http://www.plantedtank.net/forums/sh...d.php?t=160396 (By the way, there is a TON of info on LED's on that thread)



I could probably figure in a slightly higher rating since a couple of the bulbs I'm using are Geisseman Midday bulbs, but I don't know exactly what that would amount to...so...I won't.

[Totenkampf]

i would think that the geismann midday would add a good deal of PAR. i just swapped out a T5NO lamp that i am using as a midday burst fixture with these and the results have been very obvious over the oddysea junk that came with the fixture.

[davemonkey]

i would think that the geismann midday would add a good deal of PAR. i just swapped out a T5NO lamp that i am using as a midday burst fixture with these and the results have been very obvious over the oddysea junk that came with the fixture.

Yeah, I wish I had a way to measure the difference or knew where to find the info. Niko, from DFW, has said that he believes they can put out 2 times the PAR that a comparable bulb (with the same ballast) would put out. If that is true, then my light would be in the high range for sure, edging on very high.

I have my lights on a stagger with a sort-of burst like you have. I have 1 fixture coming on at 8, then other pops on at 10. Then the first gets shut off at 4 and the last at 6pm. This gives me 10 hrs total (8am - 6pm) with a "high-light" period for 6 hrs (10am - 4pm)