soil temperature - Ask Extension
What time of day should I measure the soil temperature? I always do it early in the morning before the sun hits the garden. It can easily warm up 30 d...
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soil temperature #873091
Asked June 14, 2024, 11:02 AM EDT
What time of day should I measure the soil temperature? I always do it early in the morning before the sun hits the garden. It can easily warm up 30 degrees by evening, but I use that early temperature as my guide for planting. Should I be taking an average or use the lowest reading?
Thank you for your comments
Linn County Oregon
Expert Response
Hi Linrobn,
Checking your soil in the early morning is best because that is when the soil is the coldest. Put the thermometer (soil or meat) in the ground at 4-5 inches for about 5 minutes for 7 consecutive days. This data will give you an overall average. You can also take the soil temperature between 1-2 pm to see how hot the soil becomes, again for 7 days. Shade the thermometer out of the direct sunlight.
You should not take the temperatures if the soil is very wet. We have not had much rain but some is predicted in the next few days.
Wait to plant until the soil is at least 45 degrees for most cool weather plants, i.e. brassicas and 60 or higher for warm plants, e.g. tomatoes, peppers.
Seed germination is really best and usually the fastest at 70 degrees or above to 85 degrees. Root cuttings also need about 70 degrees.
You can put row cover or plastic over the soil to heat it up quickly if need be. The sun heats up the cover and the cover holds some of the heat in overnight. Also raised beds usually heat up faster than inground beds.
Air temperature also affects soil temperature. We have had relatively warm days so your soil especially if it is in the direct sunlight should have warmed up.
If you have further questions, please contact us again.
Checking your soil in the early morning is best because that is when the soil is the coldest. Put the thermometer (soil or meat) in the ground at 4-5 inches for about 5 minutes for 7 consecutive days. This data will give you an overall average. You can also take the soil temperature between 1-2 pm to see how hot the soil becomes, again for 7 days. Shade the thermometer out of the direct sunlight.
You should not take the temperatures if the soil is very wet. We have not had much rain but some is predicted in the next few days.
Wait to plant until the soil is at least 45 degrees for most cool weather plants, i.e. brassicas and 60 or higher for warm plants, e.g. tomatoes, peppers.
Seed germination is really best and usually the fastest at 70 degrees or above to 85 degrees. Root cuttings also need about 70 degrees.
You can put row cover or plastic over the soil to heat it up quickly if need be. The sun heats up the cover and the cover holds some of the heat in overnight. Also raised beds usually heat up faster than inground beds.
Air temperature also affects soil temperature. We have had relatively warm days so your soil especially if it is in the direct sunlight should have warmed up.
If you have further questions, please contact us again.
