Ushi No Tane - Harvest Moon

Hello,
I'm trying to buy a chicken, and I've seen on the website that Chet requires me to plant 9 bags of grass behind the chicken coop. I actually planted 10 because one took up 7 squares instead of 9 (my wrong, I didn't know what those dark patches were). They all are bright green (except for one that is darker but still not enough to cut it). However, Chet still tells me I do not meet the requirements.
Am I doing something wrong? I waited till the grass started sprouting just in case he wanted more than seeds, but it still doesn't work.
I guess I have to wait till the grass is old enough to be cut, but I'd like someone to confirm this as it'll be a long time to wait!

Thanks!

Oh well, this game is all about patience after all :) Thank you!

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Don't post in topics older than 10 days old... this is almost a year old now. ;_;