Are there any strategies for growing cool weather crops (eg broccoli, beets, etc) in, say, Hawaii?
For example, could you employ a reversed Walapini where you used the cooler temps below grade to grow cool weather crops? Obviously shading would be an issue to reduce heat build-up but I am curious if this or any other strategy could be used.
By the way, after nearly eight years here, my strategy is grow what does well here, instead of trying to fight for things that don't. After all, Northerners can't have fresh pineapple usually, and papaya in the stores in the North isn't food.
Sustainable Plantations and Agroforestry in Costa Rica
You can grow in the shade and grow them in the rain season. In any case I would consider those as experiments and concentrate in the many crops adapted to the (sub) tropics (which is a very wide term).
Some plants in the cabbage family become perennial near the tropics
Diego Footer on Permaculture Based Homesteads - from the Eat Your Dirt Summit