Question: I was out this weekend and noticed the most beautiful tomato plants at several stores in my community. I am ready to get my garden growing – can you tell me when I should plant?
Answer: Great question and quite timely, since many of us have spring fever! I have noticed the same beautiful plants at many retailers in my community, as well. And yes, it makes you want to get a head start on that delicious tomato sandwich. However, you will need to proceed with caution.
The tomatoes that we currently enjoy are derived from tropical ancestors. Therefore, while we have helped them adapt to more moderate conditions through plant breeding, they still need warm temperatures – air and soil – to successfully grow and produce.
To get your tomato transplants off to a great start, they should be planted in soils with a minimum temperature of 55-60˚F. Why does the soil temperature matter? Soils that are too cool can lead to root decay, poor (stunted) growth and disease. So, how do you know if your soil is warm enough? For vegetable seeds, such as beans or squash, just insert the thermometer to the depth of the seed planting. However, for tomato transplants (or any vegetable transplant for that matter), you will need to check the temperature at a 4” depth. Soil thermometers are available at many garden centers and hardware stores as well as online gardening sites.
You should also consider air temperature. Tomatoes grow best with daytime temperatures of 70-80˚F and 60-70˚F at night. Typically, our region warms to those levels during the month of May. Now, we all know how Alabama weather fluctuates. We can wear shorts and a t-shirt one day, and then have to don a sweater and jeans the next. Let’s just say that you are trying to be the first in your neighborhood to pick a juicy fresh tomato, so you planted a little earlier than I recommended. In the event of a cold snap (night time temperatures in the low to mid 30’s), your tomatoes will need some protection. If you only have a few plants, you can cut the bottom out of milk jugs and cover each plant individually. If that option isn’t practical, bed sheets can be used to cover several plants at a time.
So, what if you just can’t resist those gorgeous tomatoes at your local retailer? I know, I know – the struggle is real. Go ahead and purchase those plants. Just be sure to plant them in a container that can easily be moved in and out of doors.
Garden Talk is written by Bethany A. O’Rear of the Alabama Cooperative Extension System (ACES). She is housed at the C. Beaty Hanna Horticultural and Environmental Center, which is based at the Birmingham Botanical Gardens. This column includes research based information from land-grant universities around the country, including Alabama A&M and Auburn Universities. Email questions to Bethany at Bethany@aces.edu or call 205-879-6964 x15.
The Alabama Cooperative Extension System (Alabama A&M University and Auburn University), is an equal opportunity educator and employer. Everyone is welcome!