This is my first year experimenting with saving seed. Two of my kale plants from last year survived and went to seed, I let them to see what would happen. Everything was going great, the pods were dry on the vine, and I cut and thrashed them last night. I left all the seed I had collected on the counter in a bowl last night, hoping to put them into envelopes this morning, but when I came to look at them after waking, I noticed that some of the seeds had sprouted, just like that, without water. What happened? I thought since I let them dry on the plant they were dry enough to store?