Can You Use Grass Seed Left Out All Winter?

Opened bag of grass seed left under deck since October. Now stringy, some seed left. Freezing temps. Is it viable? Can the stringy stuff be used like sod?

Short Answer: Toss It

The stringy material is germinated seed that died. It has no viability. The remaining dry seed? Likely low germination.

Why Freezing + Moisture Kills Seed

• Seed imbibes water → metabolic activity starts.
• Freezing ruptures cells → death.
• Repeated freeze-thaw cycles = total kill.
• Stringy = radicle emerged, then froze.

How to Test Old Seed (If You Must)

1. Count 100 seeds on damp paper towel.
2. Roll up, bag, keep 70°F for 7–10 days.
3. Count sprouts. < 50% = not worth sowing.

Or: blow across a handful. If >50% blows away as chaff, it's dead.

Storage Rules for Next Time

• Cool (< 50°F), dry (< 40% RH), dark, sealed container.
• Garage/shed = bad. Basement/fridge = good.
• Viability drops 10–20%/year even stored well.

Bottom Line

Buy fresh seed. The cost of re-seeding failed areas far exceeds a new bag. Don't gamble on compromised seed.