I have a large packet of a large assortment of seeds growing in a prepared bed. Probably 20 different varieties of flower for a "Butterfly Garden" which I have scattered in the plot. 

I don't mind weeding it, although I would like to know that I am pulling out weeds. 

For instance, it has some sort of clover in the bag, and I have clover growing all over my lawn, but not usually in the garden, should I pull out half the clover in the garden? 

The packet also says to make sure the plot is weed free, but how can I tell if a plot is going to be weed free before the weeds grow?

So far the only thing I know to pull is grass...