Here is an update from UGA Extension Irrigation Specialist Dr. Wesley Porter:
Our ample rainfall seemed to stop early later in May and into June. With the lack of rainfall we also had an excess of heat. Typically, peanuts do not require much water early in the season, but the lack of rainfall and extreme continual heat may have pushed some producers to turn their pivots on. I would say this was a good decision and recommended practice. We had depleted much of our non-irrigated soil moisture due to the hot and dry period.
As of June, we have began to pick up some rainfall from scattered mid-afternoon thunderstorms. These rains are beneficial and very welcome. However, high intensity rainfall does not do a very good job of refilling your soil water profile. Do not bank fully on these high intensity events to fully provide the required water you need.
Based on the split planting of peanuts due to the warm early season weather we will be moving into one of two stages during July, either ramping up to peak water use and then dropping off, or just getting ready to move into peak water use. The graphic below should give us an idea of where we will stand for the 4 weeks of July. Keep track of rainfall, and supplement it with irrigation. On rainfall events from 0.25” to 1” it is good to assume a 90% efficiency, and on events over 1” it’s probably safest especially if it is a high intensity event to assume around a 75% efficiency. Make sure not short yourself on soil moisture as this can be detrimental. Overwatering can hurt just as much as under-watering too. Remember this requirement is IRRIGATION and RAINFALL! Irrigation may not even be required in the first few weeks!