Winter sowing in milk jugs (Trudi Davidoff method)

Winter sowing is a seed-starting technique developed by Trudi Davidoff of Staten Island, New York, in which seeds are sown outdoors in late winter inside covered containers -- typically gallon milk jugs -- that act as unheated mini-greenhouses. Seeds stratify naturally in cold conditions, then.

Winter sowing is a seed-starting technique developed by Trudi Davidoff of Staten Island, New York, in which seeds are sown outdoors in late winter inside covered containers — typically gallon milk jugs — that act as unheated mini-greenhouses. Seeds stratify naturally in cold conditions, then germinate when temperatures are appropriate for that species, with no grow lights, no heat mats, and no indoor space required.

Per the Cornell Cooperative Extension overview of winter sowing, the technique produces hardened-off seedlings naturally adapted to outdoor conditions — unlike indoor-started plants that require a gradual hardening-off period.

Trudi Davidoff's original method

Trudi Davidoff developed and popularized this technique starting in 2000, sharing it through online gardening forums. Per the USDA Natural Resources Conservation Service blog documentation of the method, the key insight is that many plants (particularly natives) evolved to germinate from seed that experienced winter cold, and providing that cold cycle outdoors is more consistent than any indoor cold-stratification protocol.