Let's talk about what the soil temperature for planting should be. We get complaints from beginner gardeners that our seeds did not come up. The first thing we ask is, "How deep did you plant them?"
The second thing we ask is, "How warm is the soil at night where you are?" Beginner gardeners sometimes get overly excited and plant all of their seeds in the garden bed as soon as the snow melts away. The ground is still too cold at this point.
If the ground is too cold, the seeds will not germinate (come up). There is nothing wrong with our seeds; the ground is just not ready in your area of the country yet.
70°F. Soil Temperature For Planting
The soil temperature for planting tomato, eggplant, okra, pumpkins, squash, corn, pepper, and melon seeds should be 70 degrees Fahrenheit.
This means that the temperature is not dipping below 70 degrees Fahrenheit at night. If you live where the temperatures are getting down into the 30s, 40s, 50s, or even 60s at night, the soil is too cold to germinate these types of vegetable seeds.
The air temperature should be at least 10 degrees above the required soil temperature. Fortunately, you can purchase a soil thermometer to insure you are planting at the correct time in your area.
The temperature should be taken one to three inches below the surface of the soil. It is best to measure the soil temperature early in the morning before the sun has had time to warm it. The temperature should be taken three days in a row and then it should be averaged.
60°F. Soil Temperature
When the soil temperature is at 60 degrees Fahrenheit, it is time to plant your carrots, beets, beans, cabbage, cauliflower, cucumber, cantaloupe, and broccoli seeds.
50°F. Soil Temperature
When the soil is at 50 degrees Fahrenheit, it is time to plant the following seeds: Swiss chard, turnip, leek, celeriac, celery, carrot, Asian greens, collards, Chinese cabbage, kohlrabi, mustard greens, radish, arugula, rutabaga, asparagus, and onion seeds.
40°F. Soil Temperature
When the soil temperature hits 40 degrees, you can plant spinach, peas, lettuce, parsnips, parsley, Brussels sprouts, and kale.
Above are just some of the things you can plant in your spring garden. The point of this article is to let the beginner gardener know that temperature is a very important factor in planting a successful garden.