I’ve been rewatching Good Eats and carrots and beets are also happy in cold dirt.

He used playground sand he sifted and heated to 140F/60C and let cool so it’s a bit cleaner. Stashed it in sealed plastic tub in his chill chest.

Also, adding some turnips or rutabagas to your mashed potatoes adds some nice flavor. They take a bit longer to cook but it’s worth it.