Tips: Start indoors 8-10 weeks prior to the last frost. Sow seed ¼" deep and provide a soil temperature of 24ºC with even moisture. Once they grow 2" tall, thin and transplant young seedlings into 2¼" Jiffy pots. After all risk of frost, seedlings may be set in a trench 5" deep, filling in enough soil to cover the roots. Space plants 6" apart in rows 24" apart. Gradually fill the trenches in during the season. Leeks prefer full sun and soil pH of 6.0-6.5.