Question
I live in Orlando, Florida area and bought a few bare root roses on 12/31/07. It's been 3 days since my purchase. The temperature here will drop to 24F tonight and 37F tomorrow. Shall I avoid planting them in this kind of cold weather? If yes, what's the temperature cut off point? How shall I take care of these plants before I plant them into the ground?

Answer
The best time to plant your roses is when they are dormant and as you got them bare root, then they will be dormant and okay to plant now. You can even plant roses when the temperature goes down to freezing as it is only the top of the ground which is very cold, not below. To make sure your roses will stay protected after you have planted them, make a mound of soil around them to about 8 inches. You could even use compost, mulch just as long as the canes are protected. This will make them safe from any nasty drop in temperatures during the winter. Roses can even come back from 2 inches.
If you are unable to plant them right away, then dig a trench like hole somewhere in your garden, lay the roses in it on an angle with the tops sticking out of the ground and then fill the trench up with soil but leave the top 8 inches of the rose canes bare. They can actually stay there until you are ready to plant in the spring. If you have cool weather they won't start into growth, they should be fine until it warms up in the spring. All you should be concerned about with the roses is to keep the roots damp and not frozen. Rose roots will still be active when the soil underground is 40'. Planting them now means they will be making a strong root system and will take off and be a stronger rose in the spring. When roses are planted in the spring, they have to make roots before they can produce blooms and so spring planting delays flowering.
Only fertilize your roses after they have bloomed once as you want all the energy to go into root making. If a rose puts out lots of growth on top, the roots won't be able to support it. Even if you fertilize the plant, it mainly encourages top growth as the roots have to wait until the bacteria in the soil breaks down the fertilizer so the roots can use it. Many roses don't survive  winter because they are mainly just top growth. Roots have to be strong enough to shut down the plant by hardening off the canes and drawing down the nutrients to the roots. Hope this helps.