You didn't give us a sense of scale. Gross revenue, typical costs for labor and materials, which types of assets, staffing requirements, property ownership? - Unfortunately I do not have any at this time, other than what is provided...this was just a general Q, which I realize cannot be answered accurately unless have specific info!

You would not consider this the same corporation as the IT with a new or additional activity. The requirements, operational considerations and labor issues are significantly different. - Agree 100%.

For instance, you don't want to hold Real Estate in an S Corp, and IT operations won't include Tractors or EPA license for pesticide application.

"Or setup as NEW S?"

S Corp requires Payroll; is that mushroom operation of a nature that Corporate status even makes sense?

"Remove OM equipment from Sch F and report on LLC and file as Sch C"

What does "report on LLC" mean, and why would you consider Sched C instead of F? what I was referring to is LLC taxed as disregarded entity.  T/P is concerned about personal liability, so, while not claiming to be a lawyer, feel Limited Liability Company would provide this, rather than opting to be S-Corp with all the additional requirements....taking reasonable salary, etc.

Your tax payer can have all the different things going on; it doesn't all have to be under the S Corp, just because it is a Business.

"Thoughts/comments - given limited info."

You know more about all of this than strangers on the internet know. You might also seek legal input, including the differences in risk and insurance for each type of activity. - Agree 100%, has current CPA for filing S, but further research and legal counsel is definitely the right approach.