peptone plate for bombardment

After bombardment, I always get a nasty contamination which supports its growth with the peptone in NGM plate.
Nevertheless, the bombardment protocol in worm book suggest the use of 3X peptone for growth of worms after bombardment.
I wonder why I need peptone in the plate.
Can I use plate with no peptone to grow the worms?

Before bombardment, I use liquid culture to easily grow up a lot.
After bombardment, I use normal 10 cm OP50 NGM plates to quickly starve them.

We also use NGM plates not enriched peptone plates after bombardment. I prefer that the bombarded worms and their progeny not starve until the progeny are adults. To get this result, you may need to place fewer bombarded worms onto each NGM plate than you would place onto the peptone plates.