Reddit reviews Homedeco Aquarium Glossostigma Hemianthus Callitrichoides Seeds Water Grass Easy Aquatic Live Plant Fish Tank Decoration Landscape Ornament (1 PC, Hairgrass)

Allow me to chime in with u/xXJuanSanXx regarding the use of seeds. I decided I wanted to play with some I found on Amazon, so I purchased some of the ground cover and some of the hairgrass.
https://www.amazon.com/dp/B074PMLW6N/ref=twister_B071WBWCBF?_encoding=UTF8&th=1

I made "bushes" by wetting and coating rough textured river rocks and pieces of driftwood with the ground cover seeds. I germinated them in in a covered container with misting until they looked like bushes, then placd them in aquariums.
"Bushes" made by coating river rock(s) with seed.
The plants eventually all detach and float away, but remain green even so. Not recommended unless you're always messing with your aquarium, in which case they make fine temporary bushes...

I decided that the "ground cover" seeds needed to be planted with substrate since they looked fine until they floated off the rocks & wood. I also wanted to try the hair grass seeds. So I used the seeds in a couple of dry start aquariums. The seeds only take maybe two weeks to germinate, so I waited until the other traditional plants had been given a month, then sprinkled the seeds where I wanted them. Added water 2 weeks later. The vertical "cactus" looking shapes are those dried Cholla wood aquarium decorations that I filled with houseplant potting soil and added seeds to.

Dry start seed growth right after water added.

Fluval Flex 15gal (13.2gal)

The smaller (3.5gal) has nothing but seeded plants, and the larger has some baby tears and Alternanthera reineckii "Mini" from culture.
https://www.amazon.com/gp/product/B071YG8KR2/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

The hairgrass all melted after a couple of weeks, in both tanks. It looked great while it lasted...
I had over-seeded, and the ground cover just kept growing. Layer upon layer of plants, piling higher and higher, with entangled roots keeping it together as if a single plant. All my smaller shrimp decided to spend their lives in the underbrush, never to see the light of day, or the appreciateion of observers, again. So sad. But I know they're doing fine because, every once in a while, one of them allows himself to be seen, just to mock me.

EDIT: To answer further questions about final turn out:
All of the hairgrass just melted away after about 2 weeks submerged, leaving rotting stumps with which I took no action. Nothing left of that any more. No harm, no foul on the hairgrass.

The "ground cover" needs constant trimming since it seems to be trying to reach the surface. I'm actually going to try that again, just making 2 changes to what I tried this time. Still going to do it dry start method. I don't think the seeds will stay put for planting underwater.

1. In spite of "cover with sand no longer needed" I'm going to cover the seeds before germinating them because most of them seemed to fail in getting that single tiny tap root down into the substrate. Most of my ground cover seems to float just on top of the substrate. It forms caves underneath it in some places. (the shrimp love that).
   
   
2. I'm going to be really careful not to spread too many seeds. The overgrowth was due to my profligate seed spreading (I'm betting), and it might work out better with fewer plants.
   
   Now I fully expect that I'll have to do frequest trimming anyway, but I'm not ready to take a dive yet.

Hello I was going to sow it with seeds but user u/ricamac said the following :

“Allow me to chime in with u/xXJuanSanXx regarding the use of seeds. I decided I wanted to play with some I found on Amazon, so I purchased some of the ground cover and some of the hairgrass.
https://www.amazon.com/dp/B074PMLW6N/ref=twister_B071WBWCBF?_encoding=UTF8&th=1

I made "bushes" by wetting and coating rough textured river rocks and pieces of driftwood with the ground cover seeds. I germinated them in in a covered container with misting until they looked like bushes, then placd them in aquariums.
"Bushes" made by coating river rock(s) with seed.
The plants eventually all detach and float away, but remain green even so. Not recommended unless you're always messing with your aquarium, in which case they make fine temporary bushes...

I decided that the "ground cover" seeds needed to be planted with substrate since they looked fine until they floated off the rocks & wood. I also wanted to try the hair grass seeds. So I used the seeds in a couple of dry start aquariums. The seeds only take maybe two weeks to germinate, so I waited until the other traditional plants had been given a month, then sprinkled the seeds where I wanted them. Added water 2 weeks later. The vertical "cactus" looking shapes are those dried Cholla wood aquarium decorations that I filled with houseplant potting soil and added seeds to.

Dry start seed growth right after water added.

Fluval Flex 15gal (13.2gal)

The smaller (3.5gal) has nothing but seeded plants, and the larger has some baby tears and Alternanthera reineckii "Mini" from culture.
https://www.amazon.com/gp/product/B071YG8KR2/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

The hairgrass all melted after a couple of weeks, in both tanks. It looked great while it lasted...
I had over-seeded, and the ground cover just kept growing. Layer upon layer of plants, piling higher and higher, with entangled roots keeping it together as if a single plant. All my smaller shrimp decided to spend their lives in the underbrush, never to see the light of day, or the appreciateion of observers, again. So sad. But I know they're doing fine because, every once in a while, one of them allows himself to be seen, just to mock me.”

Therefore I probably just have to buy plants at a shop.