They're highly unlikely to be ripe at the same time. The idea is to basically do it the same way the native Americans did, except using robots instead of humans. Which is how gardeners do it today. You regularly walk the field, removing the ripe ears and pods, leaving behind the stalks and unripe ears/pods to check again in a day or two. Then after all the ripe ears/pods are gone you can mulch the stalks.
As I understand it right now, the corn & beans are ready to harvest when the water content falls below a certain threshold, to minimize the cost of drying it. In my region, it's a betting game against the weather. If the right conditions emerge, everybody's trying to harvest everything at once.
During this time there's also a crush for the available harvesters, semi trucks, and elevator capacity. All of which rides the ups and downs of prices.
The robots could be programmed to manage this process too.
Of course we'll need less of these crops, if we all become allergic to beef because of that tick. ;-)
