maybe, you can delete the week? or deleting the strain from the diary would remove it? Trial and error.. all else failse, you can download the images, copy the weekyl comments, delete the dairy and just re-create it. If it is that important to you.
There is some time limit to editing a havest or the review or something.. i don't pay attention too much to the details, lol.
Also, make them all diaries per strain if interested in the contests.