Apologies for the delay on this response Michael. Although I have worked in several departments with MJ Freeway, including the consulting end, I will insert here the views of our true cultivation subject matter expert, John. John is a past cultivation operator in Colorado, writes a blog.. Greenhouse is really the preferred method for several reasons. You can control your environmental factors like heat and humidity, protect from harsh elements like hail, and reduce certain costs such as security. Initial costs of the greenhouse will often be more, but with any longevity in the operation, these costs are recooperated on several fronts, including security, quality, environmental controls, etc. Aside from the prime natural outdoor environments, like northern California, greenhouses will often give better quality than true outdoor, assuming similar cultivation experience.