Do you mean styrofoam floral cubes ? Some people use styrofoam in a "raft" system to support the plant while it is growing.

Here is a link that might be useful: Hydroponic Raft System

If it is some version of this green floral foam,

http://sona.oasisfloral.com/File%20Library/North%20America/Maxlife/SO-Maxlife-Info-Card.pdf

you'd have to check if it is treated with some sort of cut stem preserving chemicals. If it is ok or clean, why not try sticking the seed a few mm deep between two halves and giving it a go...

Been there, done that, doesn't work well. I made several trials of floral foam cut into 1" x 1" x 1.5" segments that could be easily broken apart when seeds sprouted. We tried drilling holes in the floral foam and left the dust as a low density medium, tried holes of different sizes and depths. Out of a block with 40 cubes, we got maybe 2-4 successful starts. Seeds would germinate, but most didn't survive after germination. We use rockwool, and it works great for us, but VERY expensive to be shipped to Fiji. We get over 93% successful germination to harvest.