Hi Madmike
Soil works just as well and it’s more forgiving if you make a mistake. There’s a light mix soil from BioBizz that’s good for 2-3 weeks to feed your girls with nutrients. Press the soil down a bit, place the seed on top, and lightly cover it with 0.5 cm - 1.0 cm of soil, then spray it in the morning and evening to keep the soil moist but not wet. Hope that helps you a bit.
Good luck and happy growing 😉👍