Me: Water long enough at each watering so that the soil becomes moist down to just below the root zone. Water again when the soil no longer has sufficient water to supply the turf.

You: How the heck am I supposed to know when I've watered enough to moisten the soil to below the root zone?

Me: Hmmm. OK, many university turf progams have determined that 1" application of water is needed to moisten the soil to a depth below the root zone in ideal soil conditions.

You: But I don't have ideal soil, whatever that is.

Me: Well you are going to have to experiment and guess. Clay soil is going to need to be watered in multiple short bursts so the water has time to sink in and not run off. Sandy soil will need less water to to moisten the the root zone than other soils as water penetrates sand easier. Let's see, You could use a screwdriver before watering and after watering compare results to see if it will penetrate down five or six inces after watering. or you could dig a hole and see if the water has penetrated down below the root zone or...

You: How will I know when there isn't sufficient water and I need to water again?

Me: Hmmm. With Ideal soil and average temperatures, once a week oughta do it.

You: I already told you I don't have ideal soil and the temperatures range from the low 60s to the high 90s. How can once a week always be right?

Me: Dig a hole and see if the soil is moist every day.

You: Are you nuts?

Me: Alright. Look. This is what I do: I learned to recognize the first signs of turf stress due to lack of water. (curling blades and the blades don't come back up after walking on it, etc.) At the beginning of summer when rain is scarce and temps are high, I start with watering at least 1" so I know the water is getting down to below the root zone. Then I pay attention to my lawn and when it show stress signs, I water again. I keep track of how long this period of time usually is. In my case, about 4-5 days. Then I cut the water down from 1" to 1/2". If the turf doesn't shw stress for 4-5 days, I cut the water down to 1/4". If the grass show stress the next day I know I went too far and move back up to 1/2". To water properly you must be observant, learn the signs of stress and be willing to spend time expermenting. Otherwise water 1" at a time and water once a week, or when the grass shows stress.

Awesome

How much, how often.

Weather patterns generally don't follow a strict guideline....so you must decide how often and how much will give you the desired 1"....per week....rain notwithstanding.

Its only by experience will you be satisfied whether your lawn is getting enough.

without going deep into detail....as far as that advice you are hearing about watering every day....sometimes twice a day....I suggest you read material on the dangers of that.

But, considering that when grass is given too much...and by 'too much' we mean...TOO MUCH....the turf develops roots that are shallow....conversely, if given TOO LITTLE...the turf develops roots that are shallow...see...damned if you do, damned if you don't....so only by observing how your lawn develops its lushness will you be informed about what it needs.

When the grass roots are shallow---it invites harm from diseases that have no barrier to them occurring. Heat/sun/drought....all what Ma Nature throws at it --shallow rooting then invites slow growth, die-back, bareness, all what we don't want to see happening.
Proper watering invites strong roots, lush growth and color.

All this, of course, can depend too on your fertilizing program, your drainage and seeing to seeding when it should be....which is every spring or fall.

I've been told on this forum, that I should water 1 inch per week deep and infrequently

Hang on there. That advice was for the deepest heat of summer. On the average, the average lawn needs it about weekly in the summer heat and about monthly in the cooler months. When you water, water all it needs at one time to get you through the current time period. YOUR MILEAGE WILL VARY based on your soil condition, type, shade/sun, wind, humidity, cloudy days, fog, dew, grass type, grass density, mowing height, and some other factors I'm forgetting.

One inch may not be right. I have a house in San Antonio where they enforce water restrictions in the summer. I am limited to 7 hours of irrigation on Tuesday morning and night. My lawn is in deep shade but the soil is pretty poor at retaining moisture. Still I normally water 3/8 inch per week on the restricted plan. Without the restrictions I would water 5/8 inch every 10 days because my grass can go that long before wilting. But sometimes during an extended drought where the humidity drops very low, I will need to water as much as 7/8 inch per week. This time of year we are watering every 2 weeks or maybe 3.

The idea is to allow the soil time to dry out completely at the surface. When the surface is continually moist, then all the weed seeds in the soil will germinate. If the soil dries out, they will not germinate. If your neighbors are watering daily, they have "weed pressure" which they may be resolving with routine use of herbicides. Deep watering works to extend the time between watering. When the water is deeper in the soil, that cool soil is not prone to evaporation and will hold the moisture longer. The roots will realize this and grow down to capture that moisture deeper in the soil. This gives your grass much better tolerance to drought than grass watering only to a shallow depth. Every year we read about someone who went on vacation and their daily sprinkler controls failed. The entire lawn was wiped out overnight because they did not have deep roots developed.

There is no magic formula for anyone. You'll have to work out a schedule for yourself. The concepts are as written above. Water deeply and watch the grass to see how long it goes before wilting. As soon as you see any of it wilting, then water it. If it was less than a week, then water longer right away. This time of year it was shorter than 2 weeks, then water longer NOW.

If you have problems with water penetration, sometimes called hard or compacted soil, search this forum for the word shampoo and see what you find.

When I lived in LA Ca. I had to water twice a week because of the winds and sandy soil just to keep my lawns looking green.if your soil is sandy you will need to water a little more.
Bear