I know that. But I also know that a lot of seeds would have to be released from their fruit before they could germinate. The fruit would have had to, well, rot, first to release the seeds.
Not to mention that Noah likely had seeds with him in the food he stored on the ark. Not EVERY single species/kind/whatever or seed bearing plants needed to be able to survive the flood waters.
Most grains wouldn’t have made it, except for agricultural ones.
At least half (the not in fruit ones) of annuals wouldn’t have made it.
Soft fruits with seeds that need to pass through an animal’s digestive tract wouldn’t have made it.