Spring is only 3 days away!! The temperature outside right now is a brisk 22 degrees, obviously way too cold to be planting the garden, but warmer temperatures are coming!! Tomorrow is supposed to get up to 62 degrees and that’s exciting. Here in Tennessee, it can be 16 degrees in the early morning and reach 70 degrees in the afternoon. Our weather is also extremely unpredictable this time of year. We were wearing short sleeves and some had gone as far as shorts last week only to have this week’s highs in the low 40’s with bitter winds– brrrr. But with all this said, spring planting time is coming. We will be out in our gardens planting before we know it; it can’t come quickly enough though. With the swing in the weather, how do we know when it’s time to plant our garden?
To plant our gardens, we have to consider 2 important factors and knowing this information is vital.
Frost dates: Depending on the area you live in, frost dates are important. Young seeds and plants can be killed with frost being on them. Here in Tennessee, our last frost date is a 50% chance on April 17 and it goes down to a 10% chance on April 27th. To get these dates, I contacted my local agriculture extension office. They were able to give me these dates based on the last 30 years of weather data from local stations. I would recommend you contact your local agriculture extension office, you can find yours by searching – Agriculture Extension office with your county name and state in the search. (EX: Agriculture Extension office, Bradley County, TN)
What do these percentages mean? On April 17th, the chance of the temperatures getting below 32 degrees, frost temps, is at 50% and as of April 27th the chance of these temps occurring drops to 10%. But of course, I don’t want to wait until after April 27th. So I need to be prepared to watch the weather, and have a plan to cover my seeds/plants in the event of low temperatures if necessary. Your seed packets will give instructions on the backside that will say something like: Planting Instructions – …2 to 3 weeks prior to last frost…
This packet is from my favorite seed company Baker Creek Heirloom Seed Company. If you would like to receive one of their catalogs, follow the link to their site and request – it is free.
A second thing to consider is:
Soil Temperatures: Various garden seeds require soil temperatures to be at certain levels before planting them into the soil. This is because they need certain temperatures in order to germinate. Most seed packets give this information on the backside of the package. A very simple way to know if your soil is warm enough for planting is to use a simple kitchen thermometer. (I use this one)
I’ve gone out into the raised beds and stuck it into the garden soil to get a reading of the soil temps. I’ve done this on several occasions now so that I have a record of soil temps. (Soil temperatures in raised beds do warm quicker than ground level soil, so do keep this in mind). Its probe is approximately 6 inches long and you will not be planting seeds this deep. As long as the lower layer of soil is at a consistent adequate temperature, you can start planting.
Some seeds that you can plant in March are:
Carrots, Beets, and Onions -are root vegetables and grow underground.
Carrots: Carrots should be planted directly into the soil, and not started indoors. Here in Tennessee, it is best to plant them about 4 weeks prior to last frost. If your soil temp have consistently been 60-70 degrees, it is time to plant carrots, anything below is still too cool.
Beets: Beets need be planted in consistent 60-65 degrees. These can be started inside though if you prefer. If planting directly into the garden soil, they can be planted 6 weeks prior to last frost. Beets do have a really hard outer shell and it is recommended that you soak these in a shallow bowl of water for 2-3 hours before planting.
Onions: Though onions are a root vegetable, they should be treated as a leaf vegetable and protected from extreme temperatures. Soil recommendation temperatures for onions are 55-75 degrees.
Several more above ground seeds that can be planted in March are: Spinach, Lettuce, Peas, Cabbage, Summer Squash, Broccoli, Brussels Sprouts, Radishes,
Spinach: It is not recommended that you sow indoors. Spinach is a cool season plant and needs be planted as soon as possible, because it does not thrive in warmer temperatures. Ideal soil temperatures for spinach are 50-65 degrees.
Lettuce: Lettuce seeds can be started indoors about 4 weeks prior to last frost and then transplanted outside. They can also be sown directly into the soil if you prefer. Recommended soil temperatures need be 55-65 degrees.
Peas: Don’t start these inside, they need to be planted directly into the soil. Safe soil temperatures for peas are 60-65 degrees. It is also recommended you soak the seeds for 2 hours to soften the hard outer shell before planting.
Cabbage: Cabbage seeds can be planted inside 4-6 weeks prior to last frost and then transplanted outside when soil temperatures average 60-65 degrees consistently.
Summer Squash: Is another seed that can be sown inside 3-4 weeks prior to your last frost date. Soil temperatures need be consistent at 70-75 degrees. This is one of the vegetables I would recommend following the 10% frost date and then use row covers during the cool temperatures at night.
Broccoli: This too can be sown indoors if you prefer, 4-6 weeks prior to last frost, but it is not necessary. Broccoli seeds can be planted directly into the soil. Safe temperatures for soil need be 60-65 degrees.
Brussels Sprouts: Date to sow indoors is 4-6 weeks prior to last frost. This is as well, not necessary because seeds can be sown directly into the soil as well. Temperatures to plant Brussels Sprouts safely need to be consistently 60-65 degrees.
Radishes: It is not recommended that radishes be sown indoors. Seeds need to be planted directly into the soil once it has reached 60-65 degrees consistently.
As I had shared earlier, last frost dates and soil temperatures are two vital considerations with planting vegetable seeds. If you have any questions, please feel free to send me an email and I will respond as soon as possible. I live in Tennessee and we have a relatively early last frost date and it’s important that you know yours as well. Seeds need certain temperatures in order to be able to germinate and produce vegetables. I want nothing more than to hear that you have had a successful spring gardening venture. Did you find this blog helpful? Leave a comment below…
What are your spring soil temperatures like where you live?