March garden tasks: Midwest

March in the Midwest is fundamentally different north to south. Minneapolis (zone 4b) averages its last frost on May 7; Kansas City (zone 6a) averages April 13; Chicago (zone 5b/6a border) averages April 22. These differences translate to completely different March priorities. What a Missouri.

March in the Midwest is fundamentally different north to south. Minneapolis (zone 4b) averages its last frost on May 7; Kansas City (zone 6a) averages April 13; Chicago (zone 5b/6a border) averages April 22. These differences translate to completely different March priorities. What a Missouri gardener is transplanting to the garden, a Minnesota gardener is still starting under lights.

Per UMN Extension, working with your local last frost date rather than general "Midwest" advice is essential.

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Indoor seed starting by zone

Per UMN Extension and University of Illinois Extension:

Zone 4 (Minneapolis, St. Paul, zone 4 MN/WI):

• Last frost ~May 7
• Start peppers: March 1—7
• Start tomatoes: March 15—22
• Start eggplant: March 1—7

Zone 5 (Chicago, Milwaukee, Des Moines):

• Last frost ~April 22—May 3 depending on location
• Start peppers: February 20—28 (if not done)
• Start tomatoes: March 7—14
• Start eggplant: February 20—28

Zone 6 (St. Louis, Columbus, Indianapolis):

• Last frost ~April 7—15
• Start peppers: late February (if not done)
• Start tomatoes: late February—early March
• Most warm-season crops already started

Per UMN Extension, growing conditions for indoor starts: soil temperature 70—80°F for germination (use seedling heat mat); light must be artificial and positioned 2—3 inches from seedlings for 14—16 hours daily; room temperature dropped to 60—65°F after germination for stocky growth.