Orchids cannot absorb urea so the urea you are paying for is of no use. Not completely true as bacteria convert it into nitrite then nitrate which the plants can absorb. It takes a few day so if you water once a week, by midweek it's available to the plants.

If you have bare-root plants where the excess runs off, it benefits the grass and the weeds only.

Nick

Here's some good reading for you.

Nitrogen in fertilizers and the truth about Urea

Orchids are capable of directly absorbing and metabolizing urea, but a mix of nitrate and ammonium may be best for maximal growth. I don't know how much benefit there is in one form versus another. I get good results with a 2:1 ratio of nitrate:ammonium, but have never bothered to try anything else.

Thanks for the help, its nice to know where to come and ask questions, the link was a great help
Thanks again

Bear

This debate has been going on for a decade here and on other orchid forums. I've been using whichever fertilizer is on sale for the past 40 years and haven't noticed a lick of difference in the way my orchids grow or bloom.