Is it true that if I plant different plants from the same family, cucumbers and squashes the will cross-pollinate and produce bad fruits?
Plants in the Cucurbit family (squash, cucumbers, melons) cross pollinate readily, but the cross will not be expressed in that season’s fruit. The results of such a cross would show up if seeds were saved from these cross-pollinated fruits at season’s fruit and then planted. Therefore, do not collect seeds from your vegetables, especially cucurbits, for planting in the next gardening season.