Drying a wet wool blanket without taking extra precautions could either felt the wool or shrink the blanket down so small it may not even fit a toddler bed. In some cases, you can air-dry the wool with little to no blanket shrinkage, but it's always best to read the care tag's recommendations if you don't want to dry-clean it. Some wool blankets are designed to be washable. The care tag will specify if the blanket is designed to be washed at home.
When Blankets Get Wet
If your wool blanket gets a little wet, such as when used on grass wet from dew, it can probably be dried without shrinking or losing its shape. Dry the blanket either by hanging it on a clothesline out of direct sunlight or by laying it flat. If hanging it to dry, use clothespins or spring clamps to hang the full length of the blanket, rather than draping it over the clothesline.
Washing Wool Blankets
Unless the care tag states otherwise, a wool blanket isn't meant to be washed in a washing machine; many manufacturers recommend dry cleaning instead. If you want to wash the blanket anyway, you may be able to do it without shrinking the blanket. Washing the blanket is taking a big chance. Even Pendleton notes that their wool blankets shrunk when testing different gentle washing methods.
Fill the washing machine with cool water before adding the blanket. Add a capful or so of wool-friendly mild laundry detergent. Use a little less than what the package recommends for a full laundry load. Place the blanket in the water, pushing it down to submerge it. Allow it to soak for 15 to 20 minutes, then drain the water by setting the machine to the final spin cycle. Remove the blanket once the water empties. Do not use a front-loading machine, as the agitation will turn the blanket into felt.
A Second Soak
Fill the washing machine with water again without changing the temperature. Keeping the same temperature is important; otherwise, the wool may become felted. Add the blanket to the water and allow it to soak for 10 minutes. Set the washer to a final spin cycle again to remove the water from both the machine and the blanket.
Drying the Blanket
Dry a wool blanket by hanging it from a clothesline out of direct sunlight. Use clothespins or strong spring clips to allow the blanket's full length to hang from the line until it is dry. Do not put it away until it is completely dry. If you can't hang the blanket to dry it, spread it out as flat as possible, or span it across the backs of several plastic chairs.