Temperature Obsession

My weather station is showing 32.8 F outside right now (9:55 pm, March 11) but at 4:24 pm yesterday, it was 74.2 F.

My soil temperature a few days ago was 48 F, but earlier this evening it appeared to be down to 45 F. I suppose that is because of the rain last night and the lower temperatures today.

I’d like the soil temperature to be closer to 50 F before I plant peas and other early spring crops on March 17th.

I tried out my new compost thermometer this evening and found that my compost pile temperature was about the same as the air temperature, around 40 F at the time. This means it probably isn’t big enough to stay hot in the winter time. I knew that. The compost thermometer doesn’t lie.

I suspect it is also cold in the compost bin because I didn’t have enough green material to add last fall.

By the way, the temperature in the compost tumbler was a little higher, but not much. I didn’t expect it to be very hot because the compost in it was pretty much “done”.

How did I end up with a weather station, a soil thermometer and now a compost thermometer? And would this be a good time to admit that every day for the last eight plus years I’ve written down the high and low temperatures for the city in my garden journal, as reported in the local paper?

And in the morning, when I’m recording the temperatures for the previous day, I look over the historical temperatures to see if it is colder or warmer than previous years.

I might be slightly obsessed with temperatures, especially this time of year, but I’m not alone with checking temperatures of everything like this. I think most gardeners pay more attention to temperatures because temperatures can make or break our gardens at some point.

Depending on the temperature, we’ve got stuff to do!

If it is a nice temperature, not too hot, not too cold, we have to be out in the garden, gardening. We feel compelled to not waste a good temperature day by staying inside. The flowers don’t waste a good temperature day either, as shown by the red maple flower buds above, prompted to start opening presumably by the warm temperatures over the weekend, and these crocus blooms from Sunday.

You knew I’d work in a crocus picture, somehow, right? In fact, these crocus blooms reacted to the warmer temperatures by opening, too. They are a little sneak preview of what's going to be blooming in my garden for Garden Bloggers' Bloom Day on the 15th.

If it’s going to freeze, and it isn’t a good time for a freeze, we are out covering up the plants to protect them. By the way, the reason we cover is so that when the heat absorbed by the earth during the day radiates up at night, it will be trapped under the cover, providing enough warmth to keep the plant from freezing. I sometimes see people wrap up the tops of small trees, like they were lollipops. That is not going to keep them from freezing.

If the soil is warm enough, 45 – 50 F, we can plant peas. If it gets up to 60 F, we can sow grass seed, at least here in Zone 5.

If the compost isn’t heating up, we try to add more green material or water or something to get the bacteria to make the compost.

And if it is going to be hot outside, we try to stay in the shade, following it around the garden as we weed and water.

We can’t control these temperatures. We can only measure them and react to them. And as gardeners we do a LOT of measuring of them… at least this gardener does.


  1. You're right. Temperature is very important--in the plant world and therefore in our world.

    Good point about the heat radiating from the sun-warmed earth.

    I actually prefer my compost cool because the red wiggler worms would die if it got too hot. I don't know where they come from but they love all that yummy, cool kitchen stuff.

    Below freezing temperatures for me tonight so I'll be heading out in a few.

  2. Like Goldilocks and porridge, we're looking for "just right". Right now, it's a good temp for the peas and lettuce I've planted, so it's "just right". On the other hand, by June, it will be warm enough for okra and field peas and tomatoes...and thus, also, "just right".

    Ain't the world a wonderous thing?

  3. Hi, I've been following your blog since the January grays hit us here in Eugene, OR. I appreciate many things about your posts- your eternal optimism, your consistency, and how you have shown me it is OK to face each day with one question, "How will this day effect my garden?" Your garden obsession makes mine look wimpy and I thank you for that as I was beginning to think I was becoming single-minded. (And yes, I checked my peas AGAIN today and stared longingly at my cold frame sprouts). Thanks again, Lu

  4. I obsess about the temperature too, Carol. Always wanting to know what it is. And especially the wind chill and the heat index. Maybe not so much for gardening, but just because. Do I feel colder if the windchill is in the teens-no, but I do feel vidicated that I am feeling very chilly and can add another blanket to the bed!

  5. Me too, Carol. I'm always poking the ground testing this time a year! I've already planted my peas- I wanted to try to sow them earlier, but I cover them the other day with a mini tunnel and plastic- I thought I saw them poking through today :)

  6. What fun to have a weather station. I guess a lot of plants are fussy about soil temperature and air temperature. Right now the temperature in the air and soil has dropped from the 80s to the 30s in my garden. I wonder which plants will be happy today. Of course it is pouring down so they should be grateful for that. My peas were just starting to flower so I hope they will be happy about everything going on out there. I know people have been tempted to put out their tomatoes already but I will feel safer with a date somewhere around Easter.

  7. The first thing I do every morning is check the long range weather forecast. Not from one place mind you, but from two. My garden is still frozen. Bloom Day isn't looking good. I saw one bud on a johnny jump up last weekend. Then the snow covered it all up again. Spring is coming late to Boston.

  8. I am also obsessed with temps although I don't write them down everyday. That would be way too organized for my right sided brain. Cool to see how you keep things recorded and read in your neck of the woods.~~Dee

  9. I am with you writing down those temps. Pulling those weeds in the shade. Yep. Loving to see those crocus. Can't get enough of them. I hope I have some to show on the 15th and they aren't already sleeping again.

  10. I've been writing down the daily temperature even longer than you have, but I don't own a soil thermometer, much less a weather station. (I'm going to have to start dropping some clearer hints.) I try to be philosophical about the temperatures, accepting that in some years the Magnolia blooms will get zapped. I will make an exception for my Tree Peony after last year's disappointment. I'll be draping it with a sheet every night once it starts to form buds.
    Your Crocuses look great; I have one that might be in bloom for the 15th.

  11. Your temps are a lot warmer than here, Carol. The highest it got March 11 was 63 in the warmest western exposure of my back 40. It was warm enough to make some tulips emerge, however. I'm still keeping them covered with a light dressing of leaves because March can have very dramatic temp changes as you know.

    I hope that you get the soil temperature you need to plant your peas on St. Patty's day.

  12. Although I don't have a record of temperatures from year to year, I certainly do look ahead to the forecast for the coming week. March is such an up and down month; I don't know whether to uncover all my perennials yet or not. I should have crocuses blooming for Bloom Day, but not a one has made an appearance! Good luck on getting those peas planted!

  13. Very interesting post. You might be a little obsessed, but hey, this is a good obsession!

  14. You, Carol, obsessed? The mind boggles! Oh, wait ... I'm obsessed, too. Never mind!

  15. You're right, gardeners have to be following these things (temperatures and such). We had some very mild, almost hot, days last week and I was out there working like crazy. That was because I watch the Weather Channel like a hawk and knew the weather was going to return to cold and rainy days. And sure enough, it's here right now. So no, I don't think you're obsessed. Just diligent!

  16. Yesterday it was 40F. Today it is 34F, and yes, it is much colder outside. I am keeping track of soil temperature because you have gotten me curious. I've been tracking hi and low air temps for years now. What is the difference between a compost thermometer and a soil thermometer? Couldn't one thermometer measure both?

  17. Ohhhhh....I am just itching to garden. Still too early for us, winter returned!

    Loved your blog! Stop by for a chat!

    Rose Cottage Gardens and Farm

  18. "I might be slightly obsessed with temperatures..."

    You? Ha. Ha. Ha.

    Nah. You're just a gardener.

  19. I've been obsessed with the temperature too, especially since after it was 72 the day before it was 17 (!) yesterday morning, which meant that all those silly daffodils that decided it was Spring! had their stems frozen and now have their faces planted in the dirt. So depressing.

    At least I have some mid season and late ones that are still in progress, so there will be more once it warms up again.

    Okay, I know you have posted about your garden journal before, and I have decided that I MUST start using mine. It seems like such a wonderful resource and I just don't know why I haven't made the step to actually post in it every day. Too busy reading everybody's blogs, I guess.

    Keep up the inspirational work, Carol.

  20. Thank you everyone for the wonderful comments! I'm happy to know I'm in good company when it comes to taking temperatures in my garden.

    The soil is still a bit too cool for peas, but hopefully by Tuesday...

    Carol, May Dreams Gardens


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