The Radioactive Seeds were a crate of experimental vegetable seeds altered by radioactivity at the Experimental Agricultural Laboratories in Hawaii for undisclosed scientific reasons. Possibly lost on the deck of a boat, the crate washed up on the island covered in seaweed, which prevented Gilligan who recovered it from noticing the warnings on the crate. The castaways immediately became interested in the contents as an alternate diet supplement to their limited menu on the island, planting and growing the vegetables which grew at an accelerated rate into bizarre shapes and positions. The corn grew in a circle, the carrots developed into a prong and the green beans twisted into pretzel shapes. The Professor attributed their accelerated growth rate and bizarre appearances to being in saltwater, later learning after everyone had eaten the vegetables that they were radioactive. The radiation also seemed to amplify the vitamins in the vegetables, giving Gilligan great strength, Mary Ann amplified eye sight and Mrs. Howell increased energy. Eventually, the Professor figured out how to counteract the consumed vegetables by also eating their handmade soap for the hydrocarbons to counter the effects. It's unrevealed what happened to the remaining seeds and vegetables.
- Several of the vegetables mentioned in the episode include sugar beets, carrots, spinach, truffles, green peas, artichoke, Idaho potatoes, squash, lettuce, cucumber, Swiss chard and mushrooms.