Our Purple Tomatillos are Heirloom and open-pollinated. They grow just like regular tomatillos, so they are cold tolerant. They are heavy producers and will reseed. Purple Tomatillos are unique as well as tasty! Pick when the outer husk is splitting. The average size is 1 in. - 1.5 in. You will be picking these well into the fall; and they grow in zones 3 to 10. They can be directly seeded or transplanted--very little transplant shock. Their roots are not picky! Happy growing!!!