The best vegetables to freeze are fresh from the garden or farmers’ market and at their peak ripeness. Start by trimming and washing your vegetables under cold water. Remove any stems and wash under cold water. Peel if necessary. Cut to desired size, if necessary, according to their intended use (for example, carrots can be left whole or dice them for an easy soup addition).
It is very important to blanch vegetables before freezing them. It stops the enzymes that keep vegetables ripening, helps get rid of dirt and bacteria, brightens color, slows vitamin and mineral loss, and wilts and softens the vegetables so they are easier to pack.
To blanch vegetables, bring a large pot of water to a boil (use at least 1 gallon of water per pound of vegetables). Add the vegetables to the water. Once the water returns to a boil, cook the vegetables 1 to 2 minutes. Remove the vegetables from the boiling water with a slotted spoon and transfer them immediately to a bowl of ice water until they are completely chilled. Drain the vegetables well.
Tomatoes do not need to be blanched before freezing. Just wash, peel (if desired) and remove the core.