What cold temperatures at night will do to my tomatoes? You might not like to read this. Just wanted you to know this could happen.

image from epicgardening.com 

What cold temperatures at night will do to my tomatoes?  You might not like to read this. Just wanted you to know this could happen.       

Here we are the week of Memorial Day weekend.  Where did this time go?  This weekend really came up quickly. After Mother’s Day which was early. I thought we had three weeks till Memorial Day.  Whoops, we had 2 weeks.  Planters are ready for your Memorial Day.  This spring I do believe is one for the books.  It has been cool, with a few days of heat.  Not much rain, which hasn’t helped with the gardening.  Today is cloudy with 60F, tomorrow is a little warmer but still cloudy, and then on Sunday we are to see the sun.  That will warm up everything.  Looking at next week we will be in the 80’s and at night60’s. Finally, it will be a great time to be in the gardens.
 
Australia family and friends for their Saturday May 23 will have high of 61F(16C) while their nights are getting cooler.  Season is changing for them.  Stay warm, stay safe. 
 
    May is going quickly.  I know what you are thinking, I need to have my garden in.  We can’t look at the date, we must look at the weather and be aware of the air temperature day and night, and the soil temperature. As of May 20th, I just checked Iowa State map on soil temperature, and we are at 57 degrees. Lower than I thought.  Of course, we know what the daytime temperature has been and this weekend is cool, with the night temperature still at 48F. Not till next Monday night will it be in the 60’s.  I know you aren’t going to like what I post next but tomatoes, peppers and all the vine plants need soil temperature to be at least 60F.  Also, I have researched and learned that the night temperature should be 60 degrees.  Anything lowers the tomatoes will become stressed and it will affect the fruit production.   I found an article that explains the different temperatures at night and what to do.  I was asked if putting something around them would help, and it looks like it would help keep the temperature warmer.  Many of you do put milk jugs or buckets around them more for the wind but this will help with the nighttime temperatures also.  This also applies to peppers.  I am sorry to say cucumbers, squash, watermelon, melons don’t like cold nights at all, so they might not survive.
I know this is information after the fact, as next week nighttime is to be at 60F.  Just wanted you to know what can happen with these cold nights.
Nighttime Temperatures Below 60°F for Tomatoes
Tomato plants are warm‑weather crops and do not thrive when nighttime temperatures drop below about 60°F (15°C). While they can tolerate brief dips to around 50°F (10°C), prolonged exposure to this range can slow growth, reduce flowering, and cause fruit drop.  Why it matters:  Below 50°F (10°C): This is the “chilling injury” zone. Metabolism slows, pollination stops, and growth halts. Even if it doesn’t freeze, several nights in this range can set back plant development by weeks . Below 45°F (7°C): Risk of cold damage increases significantly. Some cold‑tolerant varieties may set fruit, but most will need protection. Below 32°F (0°C): Ice formation in plant tissues can kill foliage and fruit. Ideal nighttime range: 60–65°F (15–18°C) is best for steady growth and fruiting. Seedlings indoors or in greenhouses should be kept at 58–60°F (14–16°C) for healthy starts. What to do if nights drop below 60°F:  Cover plants with row covers, cloches, or fabric to trap heat. Use mulch to insulate roots and retain soil warmth. Watering at night can help, but avoid overwatering in cold, damp conditions. Move potted plants indoors or to a sheltered area before temperatures drop below 45°F.
Bottom line:  If nighttime temperatures are expected to stay below 60°F, especially below 50°F, protect your tomatoes to prevent chilling injury and ensure healthy fruit set. Consistent warmth is key to a successful tomato crop.
Hope all your plantings will be ok, and will grow, produce and be happy. 
Till next time this is Becky Litterer, Becky’s Greenhouse, Dougherty Iowa [email protected]  641-794-3337  cell 641-903-9365  Beckysgreenhouse.com  Facebook Becky Kerndt Litterer or Becky’s Greenhouse