Visa requirements for Hawaii from UK.?

You cannot work without a proper visa, in that case most likely a J-1. Working has nothing to do with getting paid. Imagine a few hundred "tourists" work in the UK in slaughterhouses and supermarkets and other venues, and when the Home Office inquires, they just tell 'em they don't get paid. They're just "volunteering."

Same thing.

Volunteer or unpaid work is still work & employment visa is required. ONLY qualified employers can obtain employment visas for their qualified foreign employees. If the employer is not willing to pay you for your work, that employer is certainly not paying for your employment visa. If volunteering through an organization, that organization has to get you your visa.

Sounds like a scam. Why would you volunteer to do farm work in US anyway, even if it was paid?

There are short-term visas for agricultural employment, but you must be PAID employee, and the employer has to apply for that visa, pay all the application fees & everything.

Paid or unpaid it is work and there are no visas for working, the employer has to apply and get them....same with orginaised volunteering the organiser applies for the visa

A volunteer job is considered work thus you need a work visa.