Soil Temps & Spring Planting Time

Soil Temps & Spring Planting Time

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…

Baker Seed Company Seed Pkt

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)

Soil Thermometer

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?






Healthy Soil, it’s necessary

Healthy Soil, it’s necessary

I really hate the idea of adding chemicals to the environment, and I’ve worked really hard to not add any to our garden.  Last fall I built 15 new raised beds and hauled in 12 truckloads of aged cow manure and compost to fill them from an area farm.  I’ve recently had a soil test done and my pH level is high, which means that my soil is too alkaline to have healthy plants.  This is important…

15 New Beds

The soil pH value is a measure of soil acidity or alkalinity.  The pH level is one of the environmental conditions that affect the quality of the plant growth.  The scale ranges for 0 to 14, mine is at 7.47.   If you have never had a soil test completed, it is very important that do so.   You can contact your local agriculture extension office and they could help steer you in the right direction.  It normally takes about 1 week to get the results.

The vast majority of vegetables thrive in a pH level of 6.1 – 6.8.  With my results I could have super unhealthy plants or no growth at all this year, who knows at this point.  I am already experiencing spinach, mesclun, and lettuce growth as being slow and not looking very healthy, the beets and carrots that I planted have not came up at all;  I will be replanting.

Nutrients for healthy plants are divided into three categories: Nitrogen (N), Phosphorus (P), and Potassium (K) – primary; Calcium (Ca), magnesium (Mg) and sulfur (S) – secondary and the third category- micronutrients contains Zinc (Zn) and manganese (Mn).    All of which are necessary.  Though this all sounds complicated, a soil test will give you exact measurements of each and then decisions as to what type fertilizer or amendments you need to add to your soil will be simplified.  With my pH level, I have a choice of three ways of lower the level:   Adding to my soil –

1).    Organic matter.  Like compost, age-composted manure, or acidic mulches such as pine needles will reduce the pH level over time

2).    Sublimed sulfur.   This is a slow acting product but it will lower pH.  This is generally an inexpensive fix and it is a natural product.

3).    Aluminum sulfate which is fast acting.  Aluminum sulfate produces acidity in the soil as soon as it dissolves, which basically means instantly.  Not organic or natural.

All three products can be purchased at your local garden center and of course you can make your own organic matter at home with a compost pile.  Instructions for composting will come at a later date.

Because I am trying to stay organic I chose to add Sulfur to the aged manure and other composted soil I have in my beds.  It’s now early March and I have tested my pH level again and it has not yet came down.  My garden is in jeopardy!  I’ve said already, I hate the thought of adding chemicals to our garden, but planting season is only a few weeks away.  I now have to make a decision…will I go against everything that I’ve worked hard “not to do” and add aluminum sulfate in order to have a good crop this year, or go ahead and plant to see what happens and allow this to be a learning experience?   And by next season, the sulfur will have lowered the pH and next year can be much better.

I’m always learning here on the homestead.  This is a great opportunity for me to keep accurate records of this year’s garden so that I can share with all of you.  Hoping that you learn from my costly mistakes and you have even more successful crops.

After much thought of the past couple weeks, I have decided to wait – I will not be adding anything that is harmful to the environment or our health.  I will see how this year goes, learn from it, and look for a better crop next year.

If this year’s garden is a failure, then I have learned something new.  We should never be afraid to take chances.  Failures make us stronger and mistakes are bound to happen but as long as we learn something, we are still successful!

What mistakes have you made in your garden?