[Italionstallion888]

mine did the same thing, I adjusted 2 things and it took off like wild fire

I moved my light to be more directly over it, and gave the hairgrass more flow. 5 clumps covered half of my 29g in a month after I did this. Root tabs were a help as well.

 

[Italionstallion888]

Those are planted to deep

 

[Italionstallion888]

You might try grabbing those ones that are poking up and pull them closer to the surface. The only reason I said they were planted to deep, when I initially planted mine, I stuck them a bit deep, and the new runners did the same thing. After pulling the new runners closer to the top of the substrate they started growing correctly. I also found the deeper I placed the root tabs the deeper the roots went, causing the new growth to do the exact same thing.

 

[Italionstallion888]

I tested this with my tank. On one side of the tank i place the root tabs completely at the bottom of the substrate, and on the other half I placed them between my substrate and sand cap. The DHG that was on the side with the lowest placed root tabs had roots that grew down. The DHG that had root tabs placed right below the current roots grew correctly. Doubling your ferts might cause more algae issues, but that all depends on your current level of dosing. There are root feeders, so they will take little from the water column.

 

[Italionstallion888]

think about it, the plants need to get established before they can send out runners. I would think having a large root mass is a good sign. I agree on the top layer being to big/thick for them to spread as well.