Get your tickets now for the 19th Annual Sourland Mountain Festival, on July 13th, before they're gone!

By Laurie Cleveland and Carole Fay | 

I grew up on a farm, and I’ve been growing vegetables as long as I can remember. When I developed an interest in native plants, I naturally thought that growing weeds on purpose would be simple – they’d been volunteering in my vegetable garden for years! I’m sorry to say that my first attempts at propagating natives were pretty dismal. I should have been taking my cues from Mother Nature!

Plants employ lots of interesting methods to ensure their survival – from seed dispersal to stratification. I’m going to share my secret for starting seeds that require cold stratification to break the seed coat – and protection from hungry critters. I started with milkweed. It’s easy to grow, looks pretty, and monarchs depend on it!

Follow the steps below to create your own mini greenhouse using a repurposed milk jug (water bottle, take-out container, etc.). Thanks to my sister, Carole Fay, for her assistance, generosity, and almost limitless patience.

Wait to plant until conditions are right! I like to sow in my dining room over winter break. What a wonderful way to celebrate the solstice! The short days before seed catalogs begin to arrive can be very dark, indeed.

Milk Jug Mini Greenhouse


  • Drill with ⅜” drill bit or smaller or hot glue gun
  • Utility knife or scissors
  • Wax pencil or paint marker (or label “where the sun don’t shine.” Permanent marker will fade!)
  • Small bucket or wash pan
  • Watering can with a sprinkler head and/or spray bottle filled with water
  • Gallon jug (repurposed milk or water jugs work well. My neighbors and my local coffee shops were all happy to share!) Must be clear or translucent – not opaque.
  • ½ gallon of potting soil (any sterile soil is fine, no fertilizer needed)
  • String, twist tie, or duct tape
  • Sand (optional)
  • Native seeds (purchase from a local source, collect with permission from the landowner, or trade with friends in your area)


  1. Read all of the instructions before you begin.
  2. Collect all of your tools and supplies.
  3. Collect and clean containers.
    • Food grade: milk, juice, water, tea, lemonade, etc.
    • Clean jugs with soapy water, rinse well, and dry.
  4. Drill at least 4 drainage holes in the bottom of the container (Equally spaced and one about an inch from the bottom).
  5. Holes should be at up to  ⅜ inch across for adequate drainage.
    • Drill, punch, or melt with a glue gun or a soldering gun.
    • Use caution and safety measures – including ventilation if melting plastic.
  6. Drill a small hole in the cap, so that you can attach it to the jug as a name or number tag.
  7.  Using the marker, draw a line around 3 sides of the gallon jug approximately 4” from the bottom. The side with the handle will be left uncut and becomes the hinge.
  8. Using a utility knife or scissors, carefully cut the jug, following the line.  Remember, do not cut the side with the handle!
  9. WAIT to plant until after the winter solstice (December 21). Seeds that require cold stratification need the winter cycle of freezing and thawing to break their seed coat. You may winter sow through February if the forecast looks cold and snowy.
  10. Pour the potting soil into the pan and add about 1 cup of water to dampen the soil. 
  11. Leave the soil in the pan for 30 minutes to soak up the water (The soil should feel like a wet sponge.)
  12. “Open” the jug and fill the bottom with potting soil. 
  13. Follow planting instructions. Orange milkweed seeds need to be covered lightly.
    • If the seeds need to be covered, sprinkle some of the remaining soil (or sand) over the seeds. 
    • Gently firm the soil, to ensure seed-to-soil contact.
  14. Gently water using the sprinkling can or a spray bottle.
  15.  Close the jug and secure it with the a string/twist tie (or use duct tape)
  16. Remove the cap from the jug and leave it off. Rain and snow need to get in!
  17.  Using the marker, label the jug including the type of seeds, date of planting, reference number, or whatever info you like. Caps make great ID tags.
  18. Place the jug outside when temperatures are consistently below 40 degrees.
    • The jug needs to be placed in full sun.
    • Be sure that it’s exposed to rain/snow to provide moisture. Do not protect the jug from the elements.
    • Secure the jug in a milk crate, tie together, or crowd them together to prevent them from blowing away or tipping over.
  19. Go inside and admire your work from the window. Relax and have a cup of hot tea. It’s cold out there!

Sunny days and snowy conditions provide the perfect conditions for these seeds to germinate – without any attention from me (except taking these pictures, of course) Brrrrrr…..


When the daily high temperature is consistently above 50 degrees, check your jugs for growth. 

When the seedlings have more than 2 sets of leaves, open the jugs to prepare for planting in their new home – and to protect them from getting too hot. You may want to move the jugs to a part shade area if you don’t intend to transplant right away.

As your seedlings are growing and your jugs are open, make sure they are getting adequate moisture. You can tell by lifting each jug.  If the jug is light, it needs water. If the plants are wilted, they need water NOW.

You can water with a wand, watering can, or a sprinkler.  I like to water really small seedlings from the bottom. I have a few pans that are about 2 inches deep.

I fill them with water and put the jugs in the water for about ½ hour.

Look at those nice, white roots! If they’re too crowded in the jug, you can cut “brownie slice” sections and transplant them directly into the ground or in larger pots to give away or trade.

You may end up with “too many” plants. Seed swaps and giveaways are a fun way to meet new friends and strengthen your native plant community! You can never have too many native plants!

Note: Beware of wildflower mixes. Please read the label carefully to see what species are included. They may not be native to your area. The Sourland Mountain is in the Northern Piedmont ecoregion. While some plants grow naturally in multiple ecoregions, others do not. If you plant something outside its native ecoregion, it may not have the conditions it needs to thrive; it may not support native wildlife; it may even be invasive! Checking a website like or (The Biota of North America Program) could be really useful in determining which plants are native to your landscape.