Quick, cover the tomatoes. The National Weather Service has issued a Frost Advisory for most of Northern Colorado early Thursday, October 2. This is a pretty close date to the one set by the Farmer's Almanac, they said October 5 for the first frost this year.

Gardening Know How says to use sheets or light blankets on garden plants, but never plastic and make sure you remove covers first thing in the morning.

From the National Weather Service:

...FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM MDT THURSDAY...

* WHAT...Temperatures dropping into the 32 to 36 degree range
tonight will result in frost formation.

* WHERE...Most of northeast Colorado.

* WHEN...From 2 AM to 8 AM MDT Thursday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if
left uncovered.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.