Re-purposed floral or produce greenhouses or the warehouses currently being retrofitted by licensed corporate growing corporations today are old, inefficient structures, not designed for year-round growing.
Many existing empty greenhouses in the real estate market, currently being purchased by licensed growers are available because they are in various states of disrepair. These often contain outdated and inefficient support systems, leaky or illfitting poly-carbonate/glass panels, and more. They typically have high costs for heating/cooling and humidifying over the growing season due to the extreme temperature shifts inside a greenhouse seasonally.
Day to day differences caused by full sunlight conditions, versus high-temperature cloud cover and humidity, can cost thousands in operating costs to keep plants safe and productive. This increases costs to producers over the year, between lack of air movement and deadly high heat temperatures inside in the peak of summer, too cold and incredibly high heating costs for these enormous, thin glass or plastic walled spaces in the winter.
All of these changes in conditions cause stress to the plants, inhibit successful plant growth, can trigger early flowering and lead to production losses from low quality and other plant problems.