Why rain euphoria doesn’t last

Last Thursday we were fortunate to have a very nice rain, 1.3″ that fell steadily over night. Now it’s Monday, and I’m already considering my next irrigation. Why? This graph holds the answer.

moisture

This is a data log of our soil moisture after the rain that fell on the night of December 15/16. The light blue line represents soil moisture at 12″, the dark blue line represents moisture at 36″. The range represented by the shading and dashed lines is the preferred range; a fully saturated soil would be at the top.

What we’re seeing here is that prior to last week’s rain we were quite dry… very close to the lower acceptable limit. We were ready to irrigate had the storm failed to deliver. Thankfully it delivered in line with expectations. Where are we now?

The rain had the clearest impact at 12″ (light blue), which is as you would expect, but it was insufficient to fully saturate the soil. At 36″ (dark blue), the rain barely registered at all. Shallow soil moisture has already dropped considerably as the rainwater wicks through the soil.

Hoping the rain forecast for next Monday turns up!

(Hat tip to our technology providers at Acuity Agriculture for a great tool!)

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