If you're like many gardeners, your yellow squash plants produce so prolifically between July and September that you can't use the delicious vegetables quickly enough. Freezing is one of the simplest ways of preserving yellow squash, and you can enjoy the flavor of the nutritious squash in your favorite soups and casseroles long into the depths of winter. For best results, harvest when the squash is firm and uniformly dark in color. Freeze as soon as possible.
Fill a large saucepan or kettle 2/3 full of water. Bring the water to a full boil while you prepare the squash.
Fill a large bowl with ice cubes and cold water. Set aside.
Wash the yellow squash in lukewarm, running water, using a soft vegetable brush. Cut 1/4-inch from each end. Cut the squash into 1/2-inch slices.
Place the sliced squash in the boiling water. Set the timer for three minutes as soon as the squash is in the water. Place a lid on the pan.
Use a slotted spoon to remove the squash from the boiling water. Drop the squash immediately into the bowl of ice to stop the cooking process. Drain the cooled squash thoroughly.
Place the drained squash in a resealable plastic bag. Insert a plastic drinking straw into the bag to suck out the excess air. Remove the straw quickly and seal the bag. Place the squash in the freezer.