Combining the room lighting with supplementary lighting - then hiding the supplementary lighting so it doesn't appear in the high-gloss cabinets - is always a major challenge.

The switches, which must be durable enough to withstand military demands and have special optics for all types of lighting conditions, are often priced as high as $500 each.

But the greenhouses on the barge were only one storey high, so there was not much need for artificial lighting.