DigitalVinyl said:

My in the groud garden has various sprouts now. However I've become
suspicious that some of the sprouts that I thought were from my seed
may not be.

Other than long term experience--how the hell do you tell these little
guys apart? It would be great if a book showed you the seedling stage
as well as the full grown.

When I'm planting something that I've never planted before what I
normally do is to plant a few seeds in a pot or plant a largish clump of
seeds and mark them with a stick. This will give me a 'sample' to
recognize.

After a while, you learn to recognize your most common weeds as seedlings.
But if you bring material (leaves, manure) onto your property you can also
bring in new and unfamiliar weeds, so there would always be a chance that
unfamiliar seedings are weeds.

basil

Little sprouts where the first seed leaves seem to almost want to
be part of a single oval, but are snipped in the middle to make a pair.


nigella(love in a mist)

The two seed leaves resemble some other plants but the first true
leaf is disected/feathery. Usually a paler shade of green

Do carrot seedlings have long thin spikey leaves

Yes, thin spikey leaves.

--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)