Of course, I didn't mean 'jet' the bed. Just to show that that hose is taking 40 secs to give a Gallon. And of course, if you spray, you're losing a lot to waste.
E&OE, I would suggest at least 4 mins. Which is much longer than you think!!
Water 'sitting'? Yes - with some soils but, if peaty or very dry, this can be misleading.
I ffirmly believe in measuring the flow & then counting the seconds every time. Same with a Drip Hose which gives 1g/ft/hr?
PS Wrote this before the last 2.