While soil and air temperatures are important, you should also factor in the number of daylight hours. The key months for growing are from March to September. The remaining months your plants will grow slowly and come to a halt once the number of daylight hours go below ten.
To have a fall or winter garden, timing is everything. If you want a plant to be at maturity by the end of September, you need to calculate when you need to sow or transplant. When calculating the number of days, you need to include the days to maturity on the seed packet. Generally, the days to maturity is from the time you so the seed outdoors or from the time you transplant a seedling.
If you want to know how many hours of daylight you have or when the sun rises and sets in your location, check out this web page titled”calendar-updates”. All you have to do is type in your zipcode and a particular date.
If you missed my post on the types of onions, check out the link.