Customers will also complain about wilting plants in the middle of the day - by having someone out there watering it at least looks like someone is doing something about it (however futile it is).

Blindly watering every single plant, no matter what is a waste of time and resources. With hand-watering, you'll get a better feel for what plants actually need the water and when they need it. In the long run, your wilting plants will be healthier for getting irrigation when they actually need it as will your over-watered yellowing ones (hopefully you'll have enough sense to stop over-watering those).

Hand watering is the best way to irrigate container plants. Even the big box stores do it.

Considering it takes 6 - 7 times more water to using overhead sprinklers than handwatering I would say overhead irrigation is a waste of resources.

How long doe's it take to hand water in the afternoon?

You water when the soil is dry and the plants are wilting. If the soil is wet, you don't water. Period. I'll ditto what plantman said, hand watering is best. Overheads, especially at 6-7 p.m. is an invitation to foliar diseases. I never, ever water towards evening, unless it's an emergency. Also with overheads, all the plants get watered, the huge pots along with the tiny containers. On that schedule the huge pots are prolly not drying out between waters and the tiny ones are drying out to the point of vascular collapse.

When he says to handwater mid-day, you can actually take advantage of the human ability to discern which pots really need it and only do those.

If you are getting plants wilting when their soil is still damp mid-day, then they need to consider some sort of lath or shade for those plants until the sun is more gentle like it is in spring and fall. Pretty soon with watering like you have been doing they'll wilt and stay that way. LOL.

Hmmm, well, no. About the only time in years that I would not agree with Calliope's remarks...

I've been tending nursery can stock for quite awhile now. My goal is to keep it MOIST. If it dries out, and wilts, I see that as a failure in my management. It is unsaleable in that condition, but more importantly it is real hard to re-wet thoroughly. Consequently, in my nursery, we water a lot.

There are things to be done to minimize the problems, of course. Shade and lath, yes. We also shift a lot of un-sold spring stock so the plants are in a larger soil moisture reservoir. A lot of my stock, both b/b and cans, is in mulch beds, not frying out there on the gravel. I'm careful about fertilizer rates and timing.

The fact is, keeping nursery stock in good health in the middle of a Kansas summer is a lot of work, actually. It means, among other things, that somebody (often me) gets out there in the middle of a 100 degree day on the end of a hose and puts the water in the pots.

I wish good luck to OP's new boss. It's a challenging job.

Brian

I agree that first sentence is worded poorly and misleading. I do not wait until my plants wilt to water. However, I also do not do a mid-day watering of already wet plant material. I am assuming the poster works in a situation where there is retail public around the plants, and they can't be watered under the sprinklers when they need touched up. And I have had crew who thought you'd have asked them to sell their first born child when you suggest they needed to do some touch up watering between the morning and evening overhead sprinkler routines. I was often the one who manned those hoses too, Brian. ARgh.

The point I was trying to make is that if the boss asks her/him to handwater mid-day a worker can actually make the decisions as to what needs it and apply it appropriately.

Also most retail situations do not have the well designed beds you do for your plant material. I was the head grower in a very respectably run private enterprise, as opposed to a box where time/employees were often too few to go around and stuff is left on cement to fry. In those situations, especially, it's extremely important to have the human decision making process going on to spare drowning plants because they're usually stuffed in there and often with no rhyme or reason as to sizes and watering needs.

We do differ from Kansas in our climate. In our river valley, the evening overhead sprinkler system can really lead to foliar melt down with fungal diseases. My goal was to make sure the last watering of the day left the pots moist and the leaves dry.

And I still wonder if they are getting wilt with wet pots, whether they are even shading some of those poor plants! They may not need more water, the plants are transpiring more than their roots can pull up and they need some sort of relief from the sun/winds.

All they need to do is bump that afternoon watering up to about 3 pm. That will help the crunch on wilting and also it'll be sufficiently dry to avoid foliar diseases by night too.
Sort all the stock that's needing more frequent watering and put it in a special section and hand water those varieties only by hand one more time.
I have a few that are really water hogs and rootbound and I started temp. setting them in no holes flats so that they catch a little more water from the sprinklers and "water themselves" a little too. That only works in hot weather and you have to dump them if it rains, though.