I'd say forget the perlite, go with nutrient film.

Hi Adriana. I'm sure that will work well but because the idea is to harvest when the grass get to about 6 - 8", I'm not sure there will be sufficient root mass to take advantage of the NFT technique. Also got to aim for max volume that is maximum plants/sq. unit area. The flat tray should give the most volume relative to other methods.

Some wheatgrass growing sites recommend vermiculite but because it is not as pH stable as perlite (vermiculite gets alkaline over time) I still think perlite is the way to go.

I'm leaning towards using overhead mist heads. The trays would have a simple rectangular framework around it; the framework would be covered by clear plastic sheeting with a few holes to allow for breathing. Kind of like a miniature green house if you will. The top of the framework is where the mist head would mount.

Since wheatgrass is ready to harvest in about 7 - 10 days, an open system will work without too much loss of nutrients.

Not sure how many harvesting cycles I can expect anyone have any idea?

Check out Sprout People

Here is a link that might be useful: Wheatgrass info

Thanks Adriana, good site.

You could also check out http://www.ewheatgrass.com

Here is a link that might be useful: Wheatgrass Forum