Picture of bean plant curling in space looking for something to
climb on.  Vegetable Seed Saving Handbook    > Seed Isolation
Distances  Seed Isolation Distances  Using Distance to Keep
Seeds from Crossing  Perhaps the easiest way to keep similar
varieties from crossing is simply to plant similar varieties far
enough apart that their pollen cannot reach each other (called
"distance isolation"). Distance isolation requires no equipment
or special skills, but it does rely on your having a good idea
of who is growing what in your immediate area (not always
possible).  Which Distance Figures to Use?  Looking at the table
below, you'll notice that there are two different columns of
figures given for safe distance isolation. The first column
shows the distances given by Suzanne Ashworth in her excellent
book on seed saving, Seed to Seed . The second column gives the
same figures as specified by the United States Department of
Agriculture.  Purity vs Ease and Practicality  As you can see,
Ashworth's distances are si