Planning tool

Seed-Starting Tray Planner

Estimate tray counts, filled cells, open cells, and the first indoor-start batch from last frost date, tray size, cells per crop, and catalog start windows.

Inputs

Last frost date

Converts weeks-before-frost guidance into calendar dates.

Tray cell count

Sizes the number of trays needed for selected indoor-start crops.

Cells per crop

Applies a consistent planning allowance to each crop in the current filtered list.

What it returns

• Indoor-start varieties that match the active catalog filters.
• Tray count, filled cells, and open cells for the selected tray size.
• Earliest seed-starting batch and estimated transplant timing.
• Internal links to local timing, hardening-off, and germination troubleshooting paths.

Regional seed-starting timing fallback

• Regional Planting Guides Use regional guides to check local last-frost assumptions before sizing indoor-start trays; 111 source-backed regional guides cover All 50 U.S. states.
• Planting Calendar Tool Convert weeks-before-frost indoor-start windows into dated tray batches
• USDA Zone and Frost-Date Planner Keep hardiness zones separate from annual last-frost seed-starting inputs

Indoor-start planning paths

• Start Indoors Seeds 50 indoor-start varieties
• Seed-Starting Planner 50 indoor-start varieties
• Seed Germination Troubleshooting Planner Troubleshoot damping-off, dry media, and slow germination before filling more trays
• Transplant Garden Planner 50 transplant-capable varieties
• Hardening-Off Transplant Planner Plan the outdoor transition before indoor-start trays outgrow protected space
• Vegetable Catalog Food crops with spacing and maturity data
• Container-Friendly Seeds Compact crops for smaller starts
• Container Garden Planner 72 container-ready varieties

Early tray candidates

• Delicata Winter Squash 3 weeks before last frost
• Hale's Best Jumbo Melon 3 weeks before last frost
• Marketmore 76 Cucumber 3 weeks before last frost
• Small Sugar Pumpkin 3 weeks before last frost
• Sugar Baby Watermelon 3 weeks before last frost
• Waltham Butternut Squash 3 weeks before last frost

Source basis

• UMN starting seeds indoors Indoor seed-starting timing and transplant reference
• UMN planting the vegetable garden Outdoor timing reference for transplant windows
• Penn State cole crops for home vegetable gardens Cool-season transplant crop reference