Planning path

Seed-Starting Planner

Plan indoor seed starts from packet maturity, weeks-before-frost timing, tray setup, light, clean media, hardening off, and catalog entries with indoor-start timing.

Seed-starting timing checks

Use seed packets and maturity dates

Check packet or catalog days to harvest so the variety can mature before frost, then use catalog weeks-before-frost timing for the first indoor batch.

Start long-season crops indoors

Prioritize crops that need a protected head start, including many long-season vegetables and annual flowers that would otherwise miss the useful season.

Use clean containers and sterile mix

Use containers with drainage holes, clean reusable trays, and a sterile seed-starting mix instead of garden soil.

Keep seedlings close to artificial light

Use fluorescent or LED lights close to seedlings so stems stay compact instead of stretching toward weak window light.

Harden off before transplanting

Move seedlings outdoors gradually before transplanting so sun, wind, and temperature swings do not shock protected plants.

Follow species-specific directions

Use indoor trays where packet, catalog, or catalog timing calls for an indoor start; each crop has its own timing and handling requirements.

Regional seed-starting checks

Pair indoor-start timing with regional frost ranges, frost-free dates, and count-back guidance before setting tray sowing dates.

• New Jersey Frost-Range Seed-Starting Garden Rutgers frost-range checks for local last-frost dates, cool-season starts, and warm-season soil readiness
• Eastern Oregon Seed-Starting Schedule OSU timing for May 21 frost-free planning, semi-arid frost risk, hardening off, and direct-seed splits
• Central Oregon Seed-Starting Schedule OSU count-back timing for a May 31 frost-free date, indoor sowing windows, and crop-level examples

Indoor-start seed candidates

• Delicata Winter Squash 3 weeks before last frost · Warm · 100 days
• Hale's Best Jumbo Melon 3 weeks before last frost · Warm · 85 days
• Marketmore 76 Cucumber 3 weeks before last frost · Warm · 58 days
• Small Sugar Pumpkin 3 weeks before last frost · Warm · 100 days
• Sugar Baby Watermelon 3 weeks before last frost · Warm · 80 days
• Waltham Butternut Squash 3 weeks before last frost · Warm · 95 days
• Black Seeded Simpson Lettuce 4 weeks before last frost · Cool · 45 days
• Early White Vienna Kohlrabi 4 weeks before last frost · Cool · 55 days
• Green Curled Endive 4 weeks before last frost · Cool · 85 days
• White Stem Bok Choy 4 weeks before last frost · Cool · 45 days
• Bright Lights Swiss Chard 4 weeks before last frost · Shoulder · 55 days
• California Giant Zinnia 4 weeks before last frost · Warm · 75 days
• Florence Fennel 4 weeks before last frost · Warm · 80 days
• Red Stem Malabar Spinach 4 weeks before last frost · Warm · 70 days
• Georgia Southern Collards 5 weeks before last frost · Cool · 65 days
• Lacinato Kale 5 weeks before last frost · Cool · 60 days
• Sweet Alyssum 5 weeks before last frost · Shoulder · 50 days
• French Marigold 5 weeks before last frost · Warm · 55 days
• Genovese Basil 5 weeks before last frost · Warm · 68 days
• Golden Acre Cabbage 6 weeks before last frost · Cool · 64 days
• Long Island Improved Brussels Sprouts 6 weeks before last frost · Cool · 100 days
• Snowball Y Cauliflower 6 weeks before last frost · Cool · 70 days
• Waltham 29 Broccoli 6 weeks before last frost · Cool · 74 days
• Chief Mix Celosia 6 weeks before last frost · Warm · 90 days
• Common Lemon Balm 6 weeks before last frost · Warm · 70 days
• Globe Amaranth Gomphrena 6 weeks before last frost · Warm · 85 days
• Indian Summer Rudbeckia 6 weeks before last frost · Warm · 90 days
• Roma Tomato 6 weeks before last frost · Warm · 76 days
• Tall Double Mix Strawflower 6 weeks before last frost · Warm · 80 days
• Toma Verde Tomatillo 6 weeks before last frost · Warm · 70 days
• Common Chives 8 weeks before last frost · Cool · 80 days
• Common Thyme 8 weeks before last frost · Shoulder · 90 days
• Evergreen Bunching Onion 8 weeks before last frost · Shoulder · 65 days
• Italian Flat Leaf Parsley 8 weeks before last frost · Shoulder · 75 days
• Black Beauty Eggplant 8 weeks before last frost · Warm · 80 days
• Broadleaf Sage 8 weeks before last frost · Warm · 75 days
• California Wonder Pepper 8 weeks before last frost · Warm · 72 days
• Dense Blazing Star 8 weeks before last frost · Warm · 365 days
• Eastern Bee Balm 8 weeks before last frost · Warm · 365 days
• Greek Oregano 8 weeks before last frost · Warm · 90 days
• Joe Pye Weed 8 weeks before last frost · Warm · 365 days
• Purple Coneflower 8 weeks before last frost · Warm · 365 days
• Tall Verbena 8 weeks before last frost · Warm · 90 days
• American Flag Leek 10 weeks before last frost · Cool · 120 days
• Tall Maximum Snapdragon 10 weeks before last frost · Cool · 100 days
• Tall Utah Celery 10 weeks before last frost · Cool · 110 days
• Arp Rosemary 10 weeks before last frost · Warm · 120 days
• Grandiflora Petunia 10 weeks before last frost · Warm · 85 days
• Green Globe Artichoke 10 weeks before last frost · Warm · 120 days
• Munstead Lavender 10 weeks before last frost · Warm · 90 days

Supporting planning paths

• Start Indoors Seeds 18 indoor-start candidates are marked start indoors
• Seed-Starting Tray Planner Size trays and first indoor-start batches from the filtered seed list
• Seed Germination Troubleshooting Planner Diagnose damping-off, dry media, and slow germination before resowing indoor-start trays
• Hardening-Off Transplant Planner Plan the outdoor transition before indoor-start seedlings leave protected trays
• Planting Calendar Tool Map weeks-before-frost starts to calendar dates and outdoor transplant timing
• Transplant Garden Planner 50 indoor-start candidates also have transplant timing
• Container Garden Planner 43 indoor-start candidates also fit containers
• Warm Season Garden Planner 31 indoor-start candidates fit warm-season planning

32 indoor-start candidates are also Either start-method entries

Source basis

• Cornell tomato growing guide 1 entry cites this source
• CSU vegetable planting guide 10 entries cite this source
• OSU Extension Eastern Oregon seed-starting schedule Eastern Oregon Seed-Starting Schedule regional seed-starting source
• OSU Extension When to start seeds indoors in central Oregon Central Oregon Seed-Starting Schedule regional seed-starting source
• Penn State cole crops for home vegetable gardens 5 entries cite this source
• Penn State plant factsheets 2 entries cite this source
• Penn State planting for pollinators 1 entry cites this source
• Rutgers NJAES Starting Vegetable Seeds Indoors New Jersey Frost-Range Seed-Starting Garden regional seed-starting source
• Seed Savers seed saving guide 10 entries cite this source
• UMN companion planting guide 2 entries cite this source
• UMN planting the vegetable garden 4 entries cite this source
• UMN starting seeds indoors 14 entries cite this source
• Xerces pollinator-friendly native plant lists 1 entry cites this source