The absorbed energy is converted to heat energy. The scenario you mention with the LED is very close to the blackbody problem known as the ultraviolet catastrophe.. There is a Wikipedia article about it here. What happens in the situation you described is that the light proof box gets hotter.
Diagnosing rust on geraniums can be a challenge for growers. Rust begins with yellow spots on the underside of the leaves and can rapidly progress with brown fungal spores called pustules in the center of each spot. The pustules are raised up off the leaf surface and feel rough to the touch.
The geranium, zonal, is an annual flower named for the horseshoe-shaped band of dark color in the leaves of most varieties. Pelargonium species come from South Africa, but through hundreds of years of breeding, the parentage of today's varieties has been obscured. Annuals Image Gallery.ow to grow: Zonal geraniums benefit from full sun and moderate to rich, well-drained, moist soil. Incorporate a slow-release fertilizer into the soil at planting time. Plant after all danger of frost has passed and the soil is warm. Space them 12 inches apart.