You'd want to prevent frost heave and frost droughting - as well as plant damage.

A possible might be to put a framework over - allowing about 24" of clearance between the frame and the surface of the soil - that you could drape with any or all of the following: frost fleece, glasshouse plastic, double-skin roofing plastic, an old window in its frame, old carpet.

You could also place a 'box' around the washing machine and pack that with, say, polystyrene to prevent the metal from chilling.

As you're planning on growing basil you might find that a similar arrangement over the top of your other raised beds will give you a growing advantage by letting the soil warm up more quickly - and extend the growing season.

If you have created your raised beds as 'table-top' grow spaces then adding extra protection could be relatively quick and easy - and certainly worth it.

Google on cloches, cold frames, table top gardening to see what's at offer that you could build/make from recycle very reasonably.

However, if you kept the washing machine for things such as asparagus peas, or beans or veg with deeper roots, and made another bed for the strawberries with that overhead protection - first for the frost and second for the bird netting -you'd probably get lovely summer feasts. And, if you set it up with automated trickle watering ... It's more affordable on a small scale.

Good idea on using the tub for plants with longer roots than strawberries. I will use it for annual vegetables. I really can't see me putting eleborate protection over and around the berries every year. However, since I only want a smaller sized bed of strawberries, I can see me building another home for them and putting permanent insulation in between the walls with some sort of anchoring device for plastic protection during the winter. We live in a very windy area, so that would help insure their survival.