You can freeze cucumbers although if frozen whole or if not blanched they will become soft and mushy and the texture will change.
Cucumbers are high in water content which expands and breaks down the cell membranes during freezing.
To prevent the cucumbers from becoming soft, mushy and soggy when frozen you should first cut the cucumbers up in slices or pieces and blanch the cucumbers by briefly boiling the cucumbers in some water for 1 minute and then immediately transfer the blanched cucumbers from the boiling water to an ice bath to stop the cooking process.
Blanching the cucumbers stops the enzymes which makes the cucumbers and other vegetables go soggy, mushy and change in texture.
Then after blanching the cucumbers, place the cut up or sliced cucumbers on a baking sheet and freeze them until solid.
Then once the cucumber slices or pieces are frozen you then transfer them to a vacuum sealed bag, Ziploc bag or freezer bag.
Blanching is necessary for most frozen vegetables as it deactivates enzymes that causes the vegetables to become soggy and mushy and change in color.
Blanching the vegetables stops the activity of the enzymes which preserves the quality of the vegetables during storage and freezing.
The naturally occurring enzymes in the vegetables can lead to deterioration of color, flavor and texture if left active in the frozen vegetables.
The two vegetables that should not be blanched before freezing are peppers and onions.
Onions and peppers including both green and red peppers should not be blanched before freezing and they can be frozen raw.
However it's preferred that you flash freeze the onions and peppers before fully freezing them to prevent them from sticking together.
Blanching helps the other vegetables by preventing them from becoming soggy and changing color and texture.
The reason frozen vegetables go soggy is because the freezing process of the vegetables damages the vegetables cell structure and causes water to be released from the vegetables when they thaw out.
The water along with the inherent moisture of the vegetables can cause a limp and soggy texture of the vegetables when they are cooked.
When the water in the vegetables freezes it expands and causes ice crystals to form on the vegetables which can damage the cell walls of the vegetables and cause them to rupture.
As the ruptured cell walls of the vegetables release water when the vegetables thaw out it leads to a soggy and watery texture of the vegetables.
To prevent your frozen vegetables from becoming soggy you should blanch the vegetables before freezing them.
Blanching the vegetables before freezing is when you get a pot of water boiling and then you place the vegetables into the boiling water for 1 to 2 minutes and then immediately after removing the vegetables from the boiling water you then place the vegetables into an ice bath to stop the cooking process.
Store bought frozen vegetables are blanched before freezing to prevent them from becoming soggy.
If your frozen vegetables are store bought and they still go soggy or if you have blanched your vegetables before freezing and they still go soggy then they can sometimes go soggy due to the boiling or steaming.
The water from boiling or steaming the frozen vegetables can further exacerbate the sogginess of the vegetables due to the added water.
Frozen vegetables may also go soggy if you thaw them out before cooking.
You can cook the frozen vegetables straight from frozen which can also help prevent the frozen vegetables from becoming soggy.
Use high heat when cooking your frozen vegetables which quickly cooks them and prevents the vegetables from becoming soggy.
You can also roast or air fry the frozen vegetables which helps the frozen vegetables to crisp up instead of becoming soggy.
And if you do thaw your frozen vegetables you should drain any excess water from the frozen vegetables and pat the frozen vegetables dry before cooking them.
And use a very hot pan and stir fry the frozen vegetables quickly to prevent them from becoming soggy.