No that is not a good idea. The newly fresh chopped/shredded vegetables will probably heat up to such a degree the new plant would die. Compost the material first then you can add the compost to the hole when you plant new plants. I do suppose the amount of dirt you put over the shredded vegetables would be key here. The person who recommended that to you might have success doing that, but you would need to get the details of how much dirt and what amount of shredded vegetables I would think. I can see it might work, but why chance it until you know more about it?
Do not dig the hole any deeper than the soil the plant is in now.
If you make any sort of loose dirt, soil.compost blend or anything else to put under the plant, then the plant can sink.
There are very few plants that tolerate having soil added above the original soil line on the trunk.
Dig the hole wider, but let the original soil in the container sit on undisturbed soil at the bottom of the hole. Back fill around the plant with a blend of original soil and the proper amendments for your soil. Often this additional material is organic matter, but composted, not freshly shredded.