When is Your Fall Planting Season Over?

Fall planting

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?

As the Calendar turns to November, and the daylight shrinks, cold temperatures can’t be too far away. Around this time last year parts of the upper Midwest got dumped on with 6+ inches of snow!

If you look at online nurseries or get any of their emails and you’ll find lots of sales. Just today (10/29) we got 3 emails promoting “shop for fall & save”.  18 of the top 25 online nurseries we monitor are actively promoting fall plating.

US low temp forcast mapBUT, as we speak the 10 day temperature forecast has much of the country getting close to or even below freezing at night.

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 is at least 4 consecutive hours of surface air temperatures below 25 degrees. Depending on climate conditions and where you live, that can be anywhere between September 15th and Dwecember15th. Many areas in the south may never experience frozen ground.

And that is the key, frozen ground at least 2 inches deep. First of all, just digging the planting hole will be a frustrating task. More importantly, the root system needs the soil to remain unfrozen until they are established.

Garden.org has a neat feature with an average first frost dates tool. Just enter your zip code for historical average first hard frost.

It’s always kind of hard to predict when the weather has turned cold for good.  Your local 10 day weather forecast should help with where your area is trending. The Weather Channel offers a 10 day national high and low temperature forecast map here.

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.

Micro climates within the same town can be quite different. I grew up along the snow belt on Lake Erie. Lake effect snows could bury folks living along the lake but a few miles inland could never see a single snowflake.

I remember growing up and trick or treating in snow and another year wearing shorts. You just never know. Mother Nature keeps you guessing.

Bark MulchIf 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.