The fist photo is 3 week old aquatica..second is 3 week old brachys(you will see some dead in there cus just threw new seeds in last years pot), both of them outdoors. Third photo is some aquatica started in my greenhouse indoors 6 days ago under a light.

I am not super familiar with growing aquatica or brachys, only arundinacea. I grew brachys once last year outdoors and it never reached the size that I have seen in pics from others. It got like 5 inches tall tops by fall.

Do they look too small for being 3 weeks old? It is still early spring here I know..I started everything early this year.

Also some people say to give grasses full sun, others say they want shade to do best..so I never know what to really do. Right now they are in full sun(when not cloudy, hey I live in the PNW)..

Right now I'm growing Aquatica and Brachystachys indoors, and last year I started Canariensis both outdoors and indoors. IME, as long as other factors don't change much (temperature, watering frequency, soil quality) any big difference in growth is due to photoperiod and type of light.

It's difficult to beat good sunlight, but Phalaris grows like crazy under good fluorescents. In the same amount of time, sunlight will encourage deep root growth rather than long stems. Also, in spring there's less hours of direct sun than your indoor fixture most likely provides.