It is very hard to identify seedlings, you may have to wait until they flower. Did you keep a list of the annuals you planted so you know what to look for?

A "weed" is any plant growing where you don't want it, so there is no rule of thumb about them. For example, kentucky blue grass is a weed in the flower bed but not a weed in the lawn. Petunias are weeds in the lawn, but not weeds in the flower bed.

I suggest you sign out a good gardening guide to annuals and another one on garden weeds from your public library and use them to identify your plants.

Without knowing the exact seeds you sowed, I can only give you some general pointers for you.

Seeds germinate when conditions are right for them. Some seeds take a long time to germinate. Others require environmental conditions to be present, such as a cold winter (which doesn't happen very much in Southern California).

Also, if your annuals grew last year, they may have seeded, meaning they had flowers and spread seeds everywhere, such as what happens with my California poppies every year.

Here's the concrete rule for identifying weeds: if you don't like it, then it's a weed. Just kidding. :-) Weds are merely plants in a place where you don't want them. You must know what the desired seedlings look like. Sometimes, this will be on the seed packets. Otherwise, you might want to try searching the Internet for a picture. Of course, you can always grow a plant from seed in a separate container to see what they look like at different stages of growth.

If all else fails, let them grow a little bigger. Pretty soon, you should be able to discern differences between the weeds and desired plants.

A useful method to identify seedlings is to presprout seeds in a moistened paper towel in a glass (fold the paper towel in three, place it vertically inside the glass so that the towel goes around touching the inside of the glass, and pour 1/2 inch of water into the glass. Place seeds between the paper towel and the glass an inch or so above the water level). This is also a useful technique to see how long it takes for the seeds to sprout (unfortunately, seeds sprouted this way are often not viable for transplant in the garden). Of course, if you no longer have seeds left from last year, it may be of no use to you right now.

Well, think I'm probably going to have to keep relying on the good people of the name that plant forum. They are fantastic btw. Everything weed and plant that we identify I am taking a picture of and making our own book of sorts on the computer for identification in later years. :) All your advice is well taken and the seedling in the paper towel is a fantastic idea. We are much more careful now on where we plant/throw seeds so hopefully this won't happen again!