The plants are suffering from sunburn. They were growing under glass in bright sun. The glass filters out the UV spectrum of light. This is the same part of the spectrum that causes us to sunburn. When you placed the plants outside they received unfiltered light. The leaves weren’t accustomed to the powerful UV rays and the plant tissue was burned, causing the leaves and stem to wilt.
Had the plant received unfiltered light on a regular basis, this wouldn’t have happened because the plant would have developed a protective response to the UV rays, including increased production of cannabinoids.
Next time, give the plant sunlight each day. It will be able to take the stronger rays as spring turns to summer.
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