MATERIALS
Clean, dry, and empty gallon-size milk, vinegar, etc. jugs. Make sure jugs are translucent – light needs to pass through.
Something sharp to cut jugs
Drill or old soldering iron (to make holes)
Tape – duct tape is great, but NOT super-adhesive kind!
Permanent marker
Potting soil
Seeds of plants that need winter chill*
PREP JUG
Cut the empty milk jugs almost in half. Leave about an inch where the handle joins the jug. (The uncut part is a hinge.)
Drill or melt 5-10 holes in the bottom. A milk jug that doesn’t drain is a BOG.
Using permanent marker, write the seed type and planting date on top of the jug.
ADD SOIL AND SEEDS
Dampen your potting soil and add 3-4 inches of soil to lower-half of jug. Press to firm.
Plant your seeds to the correct depth according to see packet directions. Better to have too few than to overcrowd your seedlings.
Firm soil again and water gently.
Close the lid and tape it shut. Make sure tape adheres to all side of cut area. Leave the top cap OFF for ventilation.
PLACE OUTSIDE
Place the jug on the east or north side of house to stay COLD. You want your seeds to stay dormant as long as possible! The later they germinate, the better.
The open cap allows rain or snow into the jug for moisture. If your seedlings dry out, sprinkle with some water. Do NOT cap your jug shut.
When your seedlings reach 2-3 inches tall, remove the tape and permit air and direct sunlight on your plants. Cut off the jug top after the danger of frost is past.
Fertilize with water-soluble fertilizer when two sets of true leaves appear.
Now they’re ready to plant in the ground, or to move into individual pots until planting time.
Permission to share/reprint granted so long as credit given to www.ColumbusGardenSchool.com
* Seed stratification = Many seeds germinate best when exposed to cold, damp winter conditions. Stratification signals to the seed that it's time to germinate when the soil warms up in spring. A moist stratification seed treatment is used to mimic the effect that winter bestows upon the seed. (from www.PrairieNursery.com)
In Ohio (zones 5/6), we generally start outdoor stratification around December 21 - January 21.