Hi Hesper,

You are correct, the information for watering does tend to be buried in other topics since it is very specific to the type of plant, garden, and site location. I have not seen a good resource for telling apart symptoms of over and underwatering since they look similar. The best way to tell which is the culprit is to dig several inches down (check in the rooting zone of the plant) to see if the soil is dry, moist or soggy. If it dried out for a very long time, it might be wet on the surface but dry deeper down. Or alternatively, there may be a compaction layer/ something causing a perched water table. For new plantings, even of xeric/water-wise plants, the soil needs to stay evenly moist, like a wrung out sponge, for a month. A gallon of water per week is a good starting point for xeric/water-wise perennials. After a month you can start to increase the time in between watering and let the soil dry out in between watering. I think the easiest way to do this is to feel how the moist the soil is a couple inches down each day and wait to water again until it is dry. Once you have an idea of how fast your soil dries out you can set up a watering schedule that is specific to your soil and site conditions. With so many factors affecting how fast or slow the soil dries out, it is hard to have a specific guide on watering frequency and amount for herbaceous perennials, it takes a bit of tinkering to get a good schedule in place and even then it sometimes has to be adjusted for weather conditions. Frustratingly, there isn't a very straight forward answer and as you learned in the training, it depends! Hopefully this helps you pinpoint the issue though. 

These FactSheets have recommendations for watering but they are imbedded in other topics: 
GardenNotes: Understanding Irrigation Management Factors
Drip Irrigation for Home Gardens
Xeriscaping: Creative Landscaping
Perennial Gardening

Best,
Denyse

Hi Denyse,

Soil moisture meters are great tools for figuring out watering schedules!

Best,
Denyse