How tough is a nut? Plenty tough, says the Boyce Thompson Institute for Plant Research. Two Institute physiologists wondered how much muscle the baby plant needs to work its way out of the nutshell; they tapped an assortment of mixed nuts, applied hydraulic pressure through the bore and took careful readings as the shells cracked open. Some of the findings:
¶ Black walnuts, gathered at harvest time, cracked at 627 Ibs. But after 135 days in warm moist earth their breaking point fell to 275 Ibs.
¶ Butternuts gave way at 665 Ibs., failed to soften appreciably after four months of...