Take a three day break and use your hygrometer or simply your index finger to feel if the soil is moist to the knuckle of your finger. If so, don't water. You really want the soil to not completely dry out between watering times, but not too much. Moist is good but saturated isn't the best scenario for Arborvitae. The good news is that Arborvitae can handle a lot of water.

There's no need to water every day. During heat spells a 45-60 minute watering 2x a week should be sufficient given they are mulched and 1x a week when less heat. Use your gauge or finger to see how your particular soil is holding water or drying.

Dax

see link re: proper watering ...

ONLY water a plant when it needs it ... any plant ...

which means.. you have to figure it all out.. in your soil.. in your garden.. with your plants ...

dig small holes NEXT to the BB planted and find out at about 3 to 6 inches.. how moist the root mass is ..

no guessing ... if you want to perfect watering ...

ken

Here is a link that might be useful: link

Thanks!