April 21, 2017 Kris Cherewyk
The Importance of Soil Temperature at Seeding Time
Hello everyone. With most of the snow melted across the province and the temperature going up it’s hard not to get excited about the upcoming seeding season. Early planting has its advantages including reduced risk of fall frost, taking advantage of early season moisture, etc. However, it’s important to remember that soil temperature plays a large role in crop germination.
Different Ideal Temperatures for Different Crops
While it is generally recommended that 10 degrees Celsius is a good soil temperature for planting, the reality is that farmers have many acres to cover and do not want to risk a late fall by delaying their seeding operations. Different crops have the ability to germinate at various soil conditions which helps in planning what to seed first. Canola and mustard can germinate at temperatures as low as 2 degrees Celsius; with that being said, there are a couple risks involved. First, these crops are more susceptible to early season frost as the growing point is above the soil. Second, various canola seed treatments for flea beetles have a limited length of time for effectiveness (anywhere from 14-35 days depending on treatment type) and once this timeframe has passed it’s open season on seedlings that are more susceptible to damage than an advanced crop. Cereal crops as well as flax and most pulses are able to germinate at temperatures around 4 to 5 degrees. Soybean germination and emergence is most hindered by cooler soil temperatures, therefore it’s not recommended to plant when the soil is below 10 degrees.
Soil Temperature Testing
To test for soil temperature, use a soil thermometer at the depth you plan to seed at and take a reading once in the morning and once in the early evening. Average those two numbers and you will have the average daily soil temperature. It is recommended to take readings at different sites in the field when there are substantial changes in topography and soil types.
With files from Saskatchewan Agriculture: https://www.saskatchewan.ca/business/agriculture-natural-resources-and-industry/agribusiness-farmers-and-ranchers/crops-and-irrigation/soils-fertility-and-nutrients/soil-temperatures-and-seeding