No worries....roots are not deep.
(said with a smidge of irony...check my name!)

As long as you get a nice full plant (it is a sunny area, right?) it should cover up the unsightly area nicely, although passers-by will want to come close and check out the plant if they have never seen one before....in the process they may notice your vent.

Yes, I just sowed several amaranth varieties in 6 packs and they come up in bunches. I will transplant into individual cells and grow them on, then transplant out. I love the many amaranths...they are fun!

yay! I'm glad I don't have to go out and buy more plants. Since this is my first year landscaping at this house, it has gotten a little expensive. I really cut costs starting by seeds! I can't wait to see this plant in person!

They also self-sow so you should have a bunch next year. As noted they are shallow-rooted, so any excess can be hoed out easily.

One of my favorites to grow. It is easy and very eye catching. In zone 7 I have to spray for pest. They love chewing on the leaves and, have had chewed until the leaf looked like a tea strainer. I love all the varities of amaranth. They are truely a show stopper in this tiny west Tn. town. I use in almost every arrangement I do. I plant a long row in the cutting garden just for this. Hope you also fall in love with this plant.