Michigan State University Extension
Preserving Food Safely - 01600649
Winter squashes all freeze well, but they may lose their original texture. Summer squash is best suited for soup after it's been frozen, but freezing is the only way to keep it for any length of time. To freeze pumpkin and other winter squashes, wash, halve and remove seeds. Leave squash in halves or peel and cube it. To make a puree, bake the pumpkin and winter squash halves in a 350 degrees Fahrenheit oven until soft. (Steaming is also possible but will make a wetter puree). Scrape the meat out of the shells and mash thoroughly or run through a food mill. If preparing cubes, peel and steam the cubes until soft. Leave cubes whole or run a food mill or processor. Pack into containers. Seal, label and freeze.
To freeze zucchini and other kinds of summer squash, cut in half, remove seeds, if necessary, and cut into cubes. Steam blanch the cubes for two to three minutes. Drain well and pack the cubes in containers, or mash them or turn them through a food mill before packing. Seal, label and freeze.
If you grate zucchini with the skin on it will stay crunchy when frozen without blanching. Use the side of the grater with the largest holes, or use a food processor with a coarse shredding plate. When you thaw the zucchini, drain it and save the juice to use in soups and breads. Add shredded zucchini to quick breads, omelets or spaghetti sauce or layered in lasagna, where it will provide some flavor but mainly texture.