Soil Temperature is Key to Success

I am a terrible gardener. Though this column is about the importance of soil temperatures for fall gardens, my lazy gardening practices come into the discussion later. 

Plant roots grow in soil that provides nutrients, structural support, moisture and microbes. The health of your food and ornamental plants begin there. During the day, soil collects heat and keeps the roots warm at night when air temperatures fall. 

Soil temperature is more important than perfect watering methods, fertilizers and pest protections. The optimal soil temperature for seedlings is easy to find on company websites, seed packets and at online databases such as

This week I was searching for ideal germination temperatures for fall-planted greens because seeds by the scoop purchased at Arnold’s Fruit Company in Muskogee come without growing tips. 

According to Oklahoma Mesonet at, soil temperatures at 4-inches deep have dropped from 85 to 75 in the past week, making it possible to plant fall vegetables. These seeds will not germinate if the soil is 85 and prefer the 70-degree range.

It’s all about roots and shoots. Seeds absorb water and form a root before they produce a shoot above ground. Spinach wants 75-degree soil, lettuce wants 60-75 degrees, radishes and chard 65-85, etc. (

Now, back to my being a terrible gardener and how that connects with this topic. In our garden many plants are allowed to go to seed because we collect the seed to use next year, the seedheads are beautiful, fall migrating birds enjoy feasting on them and their tall weedy structures in the pollinator beds provide cover for butterflies and their babies.

As fall cleanup in the ‘lazy-gardener’ sections began this week I found tiny seedlings of parsley, kale, cosmos, castor bean, and zinnias signaling cooler soil temperatures just right for new seeds. 

We also leave weedy places for turtle habitat after finding them nesting among thick weeds we had ignored all summer. Feel free to use our ‘habitat for wildlife’ excuse for your weeds.


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