Mache should be grown during cooler parts of the growing season, during early spring or fall, and can even be grown over the winter season in many zones. It can withstand temperatures as low as -20 degrees F, although a cold frame or greenhouse should be used if freezing rain, wind, or heavy winds are a concern.
Mache should be grown in a cool site, and will show better germination rates with soil temps between 50-70 degrees F. Warmer temperatures may deter germination. Sow seeds lightly, approximately ¼-1/2" deep. Germination should occur between 7-14 days.
Space seeds 1"apart if direct seeding, and thin to 3-6" between growing plants, with 4" between rows.
Mache will grow in a wide variety of soil types. For best results, the growing medium should be rich in compost and other organic material.
As they mature, mache plants will form a rosette of medium to dark green leaves that are elongated or slightly cup shaped. Thin the plants as required to provide room for them to reach full size and transplant or eat the thinned mache leaves.
Plants will complete their growth cycle in 40-70 days, depending on conditions.
Water moderately, and fertilize with an all-purpose blend if needed. Mache can be grown in full sun to part shade, but can be sensitive to heat and is more appropriate as a cool season crop.
Image Credit Flickr Creative Commons - Andy Roberts - https://www.flickr.com/photos/aroberts/