Drape your raised garden bed in cloth? Certainly! You're a sewing and fashion maven--silk cloth? Linen? Cotton?
Here's a fashion raised bed gardening tip: Cloth mesh works better than designer cloth in raised bed gardening. Clothes aren't just decorative--they keep out the pests (except for that guy in the bar last week). Many gardeners use the raised bed gardening technique of placing bird mesh around the narrow bed. Suspend the bird mesh on flexible conduit frames, especially around your tomato plants.
While raised beds are an effective gardening technique to control temperature, especially in rows of leafy crops, you can use cheesecloth if you want to maximize the heat. Plastic cloche greenhouses are another attractive option.
You can start plants under plastic covers and never have to transplant them--they'll grow to full maturity! Besides, you'll look a little nutty or "green" if you drape your raised bed in gabardine.