Those of you who have some experience working your garden know how important it is to monitor the temperature of soil. Knowing the soil temperature tells you when to plant or seed. For example, planting flora or vegetables or seeding should not be performed when the soil is too cold or the plants will die.
Moreover, plants and vegetables tolerate different soil temperatures. Crops that thrive in soil temperatures down to 40°F include arugula, fava beans, kale, lettuce, pak choi, parsnips, peas, radicchio, radishes, and spinach seed.
Vegetables that tolerate soil temperatures at or higher than 50°F include Chinese cabbage, leeks, onions, Swiss chard, and turnips.
Warm-season vegetables can tolerate soil temperatures at or beyond 60°F. They include beans, beets, broccoli, Brussels sprouts, cabbage, carrots and cauliflower. However, experts caution that you should monitor the weather as well because beans will not tolerate frost and may have to be planted twice if the temperature goes below freezing.
Vegetables including tomatoes, eggplants, peppers, cucumbers, squash, corn and melon thrive in soil temperature of 70°F and higher.
Spring bulbs can be planted when soil temperature drops below 60°F.
It is suggested that you apply crabgrass control in the spring when soil temperatures reach 55°F for four to five days in a row.
Plant cool-season grass seed when soil temperatures are in the 50s F.
Plant shrubs before soil temperature drops below 40°F to give the roots time to grow.
So knowing soil temperature is essential to the life of your crops and plants. Ascertaining soil temperature is achieved with the use of a soil temperature thermometer.
A soil temperature thermometer generally includes a coated probe that can resist corrosion. Still, there is some maintenance that needs to be performed so that corrosion does not develop. For example, experts suggest that you wipe down the thermometer to remove soil and salts to extend the life of the probe. If you live in a wet environment, be sure to wipe the probe clean and dry it before putting it away after use. Many soil thermometers come with some kind of cover including a case or clips to protect them while they are stored.
There are quick reading thermometers that are ideal for a quick probe of soil to ascertain conditions. There are also thermometers that need some time to achieve their reading. This variety of thermometer needs to be left in place in the ground for a few seconds to generate a stable reading.
Soil temperature thermometers cost just a few dollars and can be found at local garden centers.
How To Use A Soil Temperature Thermometer
A soil temperature thermometer can perform a measurement in six steps:
1. Determine the proper depth to perform the measurement. If measuring for a mixed garden, the depth should be at least 5-inches to 6-inches.
2. Use a screwdriver to make a pilot hole. This ensures that the thermometer’s probe will not be damaged if forced into hard soil.
3. Insert the thermometer into the pilot hole and follow the directions supplied with the thermometer.
4. Provide shade if the sun is bright. This can be achieved by simply putting your hand between the sun and the thermometer. This ensures that the reading is accurate.
5. Take a reading in the morning and late afternoon, and then average out the results. If you are seeding a lawn, take measurements on all four sides of your house because some areas warm quicker than others.
6. Check the reading.
(Next time: What is and how to use a compost thermometer)