When Is Your Fall Planting Season Over?
It happens around this time of year. We’ve been receiving quite a few emails asking if it’s still a good time to be planting. Fall is considered the best time of year to plant but when do you know the planting window has closed?
With Pumpkins on porches, cooler nights and shorter days, it is obvious steady colder weather isn’t too far away. There are already parts of upper elevations of various mountain ranges across the US that have snow cover!
If you look at online nurseries or get any of their emails you’ll find lots of sales. 18 of the top 30 online nurseries we monitor are still actively promoting fall plating.
As we write this, the 10-day temperature forecast has much of the country getting into the low 40’s or upper 30’s. You can view the national 10-day temperature map at https://weather.com/maps/tendayforecast.
So, when is fall planting season over for you? We checked with our local state agricultural extension office and the consensus was fall planting is best completed roughly 3 to 4 weeks before your first typical hard freeze.
Okay, so what is a ‘hard freeze’? According to the National Weather Service; A hard freeze is when there are at least 4 consecutive hours of surface air temperatures below 25 degrees. Depending on climate conditions and where you live, that can be as late as December 15th. Many areas in the south may never experience frozen ground.
So, that is the key, frozen ground at least 2 inches deep. First of all, just digging the planting hole will be a frustrating task in futility. More importantly, the root system needs the soil to remain unfrozen until they are established.
Garden.org has a neat feature to help you with fall planting date ranges. They list the average first frost dates tool. Just enter your zip code for the historical average first hard frost.
It’s always kind of hard to predict when the weather has turned cold for good and fall planting season is over. Your local 10-day weather forecast should help with where your area is trending. I grew up in the ‘Snow Belt’ on Lake Erie. I can recall trick or treating as a kid in the snow. Another year I was in shorts. Mother Nature keeps us guessing. The point is that unless you historically have frozen grown within 4 to 6 weeks from when you are considering buying outdoor plants, your fall planting season is over.
Other things to consider include if it is going to be cloudy or sunny. Wind or calm? No wind overnight will allow colder air to hang around close to the ground. But a cold wind will sweep away warmer air. Sunny days will help warm up the ground to hold off some colder temperatures.
Microclimates within the same town can be quite different. Lake effect snows along the infamous ‘Snow Belt’ I grew up along could bury folks living along the lake but a few miles inland could never see a single snowflake.
If you believe it’s going to be a while before your ground will freeze 2 inches or more below the surface, it’s probably safe to plant.
You can also do a few things to help protect the time & money you’ve invested. Mulch heavily (2 to 4 inches) around your new plants. Worst case scenario, invest in some frost protection plant covers if extended freezing weather is hitting earlier than expected.
Interested in knowing why Fall is the best time to plant trees and shrubs? Read our blog piece here.