By Kristina Hughes, Clear Creek County Master Gardener
’Tis the season to start thinking about fall and wintering watering. And in Colorado, it is always the season to think about how to water effectively and efficiently. A few years ago, I was tasked with watering a large planter full of perennials. I directed the hose at the planter for what felt like a good long while. I went back the next day to find that the plants were wilted! I stuck my finger in the soil and it felt moist. I was perplexed.
I thought about it for a while and then dug out a tool I had hardly ever used: a soil moisture meter. It had prongs that reached 8 inches deep, much deeper than the tip of my finger could reach. When I stuck it in the planter the potting mix was very, very dry. Ah hah! This time I watered the planter until the moisture meter told me it was moist 8 inches down. The plants were much happier.
Since then, I have frequently used my soil moisture meter to make sure the soil is moist where many of the plant roots actually are, 6-8 inches down.
And I have been surprised a few times. I was working in a native plant garden this season. We had gotten a lot of moisture in late spring, but then went through a dry spell and the soil seemed to be dry in this garden. I used the moisture meter to double check and found that the top 2-3” of soil was indeed very dry, but deeper down it was still plenty moist. And when I looked at the plants (natives, every one), they looked fine even though they had gotten no rain or water in weeks. (A testament to native plants and a thick layer of mulch!)
I have to say that the soil moisture meter has become one of my favorite tools for gardening in Colorado. It helps me assess the conditions deep in the soil without having to dig holes After all, half of most plants’ mass is underground where we humans don’t see what is going on.
The inexpensive soil moisture meters available at hardware stores (the kind I’ve been using) are definitely less robust than the expensive scientific instruments used by commercial operations, but I have found mine to be very useful especially when combined with other observations from the garden.
So that’s another tool which can help with water management in your landscape. Remember to support your woody plants with water during long spells of warm, dry weather in the fall and winter (see the PlantTalk article on winter watering below for detailed instructions). PlantTalk 1706 - Fall & Winter Watering https://planttalk.colostate.edu/topics/trees-shrubs-vines/1706-fall-winter-watering/ An assessment of Portable Soil Moisture Meters from University of California Cooperative Extension http://ceventura.ucanr.edu/Com_Ag/Subtropical/Publications/Irrigation_229/Portable_Soil_Moisture_Meters_-_1993/