This may seem like a non-problem to some, but I very often find myself with a handful of seeds and I totally forget what the seed spacing, row spacing and seed depth is supposed to be for any particular variety. I usually keep my seeds in a separate container and throw away the packet after planting one or two rows, then they get mixed up with others of the same type (hopefully).
Example:
I go out and I plant two rows and beets, two rows of turnips, two rows of radishes and two rows of carrots. I know from repetition that beets and turnips should be 3 inches apart and half an inch down, carrots sort of just rest on top of the soil and scattered in a line and radishes are like 2 inches apart and 1/4 inch apart.
Unfortunately, that's not always what it says on the seed packet, so I'm forced to re-calibrate.
What is an effective method for recollecting all the info on all the varieties of plants you're going to plant on any given day?