Are you talking about rock wool cubes? Many brands and "Hydro Cubes" is one brand of them.

If so they are used in hydroponic set ups - either wick or drip or capillary matting set-ups and are watered by whichever hydro system you use. They are not used in soil set-ups.

The water used on them has to have its pH adjusted before use down to 5.5 pH so in that aspect alone they are quite different and more work than peat pellets.

Lights used etc. isn't any different. Size of the cubes varies greatly so how they would compare to peat pellets would depend on which size you used.

But the biggest issue is if you would be transplanting your seedlings to soil then they don't work well. They do not break down in soil when buried and since most of the roots are embedded in the rock wool further root development can be stunted. They are intended to be transplanted to larger hydro cubes and then to blocks and then to slabs.

If peat pellets work for you, stick with them for best results.

Dave

Thanks for your reply Dave, the ones I was looking at where called "Oasis Horticubes". But from what you tell me it's a lot different then using soil/peat pellets.