Kaleidoscope Carrot seeds produce a rainbow hued mix of the vegetable, and each carrot grows to 2 inches wide and 4 to 8 inches high. Each packet comes with 500 seeds that take 10 to 14 days to germinate and 75 days to mature. Seed packets from Hudson Valley Seed Library are called “Art Packs” because each year the company commissions new works for art so that each of the packets is designed by a different artist.