How did the old-timers water their crops?

I think they generally prayed for rain. When none came their crops failed and they tried again the next year.

I think a key to their success also was growing crops suited to their area. Growing thirsty crops in arid areas is now and never was a great idea.

They didn't always water the plants. Around here, they kept all weeds and grass out of the gardens and fields and spaced the plants a lot further apart than is recommended now.