With a point you are probably using a shallow well jet pump.
You can use a relay to start the pump. However, the easiest way is to use a pressure tank with a pressure switch. The pump will keep the tank pressurized and will start the pump when you start irrigating with hose or sprinkler system.
I suggest that you take care to match the pump and watering system so the pump runs continupusly when you are watering. Set the switch shutoff pressure to about 5 to 10 psi less than the shutoff pressure of the pump (experiment) and use a sprinkler on the end of the hose so it is not being shut off frequently.