Planning tool

Seed Germination Troubleshooting Planner

Use catalog germination days, temperature ranges, sowing depth, start method, medium moisture, light, and damping-off risk to decide whether to wait, warm, re-sow, or change the seed-starting setup.

Planning tool

Current germination check

10-day no-sprouts check

No sprouts yet: For no sprouts yet, compare 10 days since sowing with each catalog window before re-sowing.

Days since sowing10 days
Past window4 crops
In window88 crops
Too early11 crops

Default 10-day no-sprouts check

No sprouts yet: For no sprouts yet, compare 10 days since sowing with each catalog window before re-sowing.

Past catalog window (4)

Still in catalog window (88)

Too early to call failed (11)

Inputs

Common seedling age presets
Start with this week, one week, default 10-day, two-week, or three-week seedling-age presets before typing an exact day count.
Exact days since sowing
Keep exact day-count entry available for labeled trays, row markers, seed-starting logs, and crops with unusual germination timing.
Catalog germination range
Compare the seed entry germination temperature range with the measured growing medium or outdoor soil temperature.
Catalog germination days
Use each entry expected days-to-germination window before assuming a tray or bed has failed.
Sowing depth and start method
Check whether the seed is shallow-sown, direct-sown, started indoors, or handled either way before changing cover, light, or tray conditions.
Growing medium moisture
Compare the tray or seedbed with source guidance for moist but not soggy media and continuous moisture during germination.

What it returns

Planning guidance

Medium temperature
UMD says 65-75F is best for germinating seeds of most plants, and that this is the growing medium temperature, not the air temperature.
Continuous moisture
Seed germination begins with water absorption; after it starts, a dry period will cause the death of the embryo.
Plastic covers
Clear plastic can raise humidity and temperature, but remove the plastic as soon as sprouts appear so seedlings are not held under excess humidity.
Warm mix
UMN notes that seeds started indoors germinate sooner and produce healthier roots when the potting mix is warm.
Depth and light
Use package or catalog depth first; UMN uses two times seed width as a fallback and notes some seeds require light to germinate.
Weak seedlings
Lack of light is the major cause of elongated, skinny stems, so germination success still needs immediate light after emergence.
Damping-off boundary
UMN associates low light, overwatering, high salts from over fertilizing and cool soil temperatures with increased damping-off risk.
Outdoor soil check
Plant when soils reach minimum temperature measured at 8 a.m., 4 inches deep; CSU also notes high soil temperatures that may interfere with seed germination in summer.
Catalog boundary
Candidate lists come from catalog germination days, temperature ranges, and sowing depth; the source notes explain how to interpret those values before re-sowing.

Slow-germination candidates

Warm-medium candidates

Shallow or light-check candidates

Supporting planning paths

Source basis