(brrr)
How many plants are you growing? Anything else like peppers, etc. ?
Time to do a full inspection real close. Have you had any warm days?
Sometimes one early Spring hatched pest gets in with an open door or groceries
and hangs around for a bit, dies, moves on, etc and that's the end of it...
or worse, laid some eggs.
Just keep an eye on it so you can nip it quick if it is a pest. Aphids, etc.
I keep on hand food grade DE, h peroxide 3%, Neem, and a basic castile soap.
Oh, good idea to hang a yellow sticky trap for an early warning sign.
Any plants coming in from outside or from a nursery or grocery or big box store gets
a big hose spray, soil drench, then peroxide 4-1 soil wash, neem spray on foliage.