Warm soil, cooling weather - Perfect Time to Plant Native Plants

Ah, the feel of warm soil

Mid-September is a fantastic period to plant native plants in Redding, CA. The recent refreshing rains have somewhat softened the warm ground, making this an ideal time to prioritize planting.  Although the main rainy season has not arrived yet, soil temperatures are expected to remain warm for at least another month.  This golden window is perfect for giving your new plants the best possible start.  Warm soil combined with cooler ambient temperatures promotes both root growth and development.  While there is variation among plant species regarding their rooting responses to soil temperature, root growth typically peaks when soil temperatures are in the 60s °F range.

According to the local CIMIS (California Irrigation Management Information System) at Shasta College — Station 224 — current readings indicate a soil temperature of 73°F.  Historically, soil temperatures in Redding remain above 60°F until late October.  As temperatures decline, roots tend to grow deeper, searching for that perfect blend of warmer, moist, and oxygenated soil.  For those interested in more comprehensive data, registering and logging into CIMIS provides expanded access.

Playing in the soil

When planting prior to the onset of consistent rainfall, it is essential to prevent the root ball from drying out by watering deeply when the top inch or two of soil becomes dry.  Applying two gallons of water delivers approximately one inch of moisture to a circular basin with a one-foot radius, sufficient to moisten soil to a depth of 8–12 inches—effectively reaching just beyond the bottom of the root ball.  This robust root development in autumn, continuing to a lesser extent through spring, establishes a substantial root network that enables more efficient nutrient and water uptake during the blasts of summer heat next year.