I'm trying to figure out when is the best time to plant my corn. From what I've read corn is very sensitive to cold and one site said to plant only after ALL chances of frost have passed. So looking at the frost dates there are different numbers: 10%, 20%, 30% and so on. So which date should I be going by for corn? Should I go by the 10% chance?
Location: Currently in Lake Stevens, WA. Home in Spokane
posted 4 years ago
You didn't say where you are. Corn does not like frost, but loves warmth. If you are in a short season area, with minimal summer heat, you might want to try the 10% date for your first planting, then in a week or two (if time allows) plant the rest.
You need to look at last frost, first frost, and how many 'days' is the corn. In a short season area, you need the right corn, and the right planting time. In long season areas, almost anything will work.
In the East, there seemed to be a tradition (perhaps deriving ultimately from the Native Americans) to plant corn when oak leaves were at the "mouse-ear" stage. Observation confirms that this is by and large just past the last frost for any particular year, even though this time may vary by several weeks at a given location over several years. Determining seasonal climate by this method, called phenology, is more accurate than any kind of map or calendar or average, since you are using the sensitivity of native plants to follow that particular season's progress.
Here in CA though I think this "rule" doesn't apply. Many plants both native and exotic seem to jump the gun on spring, blooming and leafing out improbably early. Oaks may be seen budding out at the same time as plum trees in bloom (though this may happen a month apart "back East") I think this has to do with the long hot rainless summer.....plants have to get all their growing done early before settling down to endure.....
The standard guideline for determining earliest planting date is when morning soil temperature at a 2 inch soil depth is 55º F or 50º F at a 6 inch soil depth. Planting before the soil temperature is warm enough for germination greatly increases the potential for stand failure.
Soil temperature may vary depending upon soil texture, slope, color and amount and type of crop residue. Thus, randomly measuring soil temperature with a thermometer within a field should provide a reliable indicator of desirable conditions for stand establishment.