Soil Temperature & Soil Moisture Charts

Soil Temperature (C) Soil Conditions
Less than -6 Degrees

Deep Freeze - Winter Kill Possible

Less than 0 Degrees

Frost Line - Soil Frozen

Less than 10 Degrees

Too Cold To Plant - Root Growth Only

10 - 14 Degrees

Minimum Growth - Optimal Root Growth

15 - 24 Degrees

Optimal Shoot Growth

25 - 32 Degrees

Ideal Growth - Shoot Growth Only

Centibar Reading Soil Conditions
The centibar (cb) is an agricultural unit of soil water tension (water pressure on plant roots)
0-10 cb

Saturated Soil.  Occurs for a day or two after rain or irrigation.

11-30 cb

Soil is adequately wet (except coarse sands which are drying out at this range).

31-60 cb

Usual range to water (except heavy clay soils). Water at the upper end of this range in cool humid climates and with higher water-holding capacity.

61-100 cb

Usual range to irrigate heavy clay soils.

101-200 cb

Soil is becoming dangerously dry for maximum production.