This is what the jugs look like right now. This is not my photo. My jugs are in a packing crate from work and are out on the back stoop. We (here in Maine) still have freezing nights with still cold but sunny days. The bottles heat up during the day and freeze at night. It's called "stratification" on seed packages. Perennial seeds need a cold stratification to germinate. I am trying to germinate a number of self seeding "tender" perennials in the jugs. Lupine seeds would have been a good choice but I didn't have any. Swamp milkweed is another good choice for the jugs. I also am trying to start onion and shallot seeds. I may need to try those again later in the month of March. It may have been too cold. I have Blue Fescue ornamental grass in one jug. We could have also germinated more of G's chestnut seeds this way.
This is what the jugs looked like whenever we have had snow. It's okay if some of the snow or rain that falls goes into the open top of the jugs. The jugs have drainage holes drilled into the bottoms.
The directions call for drilling the holes in the bottom of the jugs or two liter bottles (clear or translucent--not the ones you can't see through) and then cutting the jugs open from the side leaving the handle section attached to the bottoms. I insert the point of the scissors--strong utility scissors-- just about where the handle exists and then straight around the equator of the jug to the opposite side of the handle. So I have 4 to 5 inch of depth in the bottom section for the soil and seeds.
The fill with a seed starter mix of soil (moistened enough to resemble moist chocolate cake-usually best with lukewarm to hot water), plant your seeds, follow package directions for coverage of seeds (some like to stay on surface, some like a light dusting and others like a quarter inch or more over the top. The add a label stick inside, close the top of the jug over the bottom section and tape shut with some duct tape. I also followed directions and wrote the seed names on the front side top of the jugs with Sharpie and covered the writing with clear packing tape--so it won't fade.
The jug acts as a small scale greenhouse for the seedlings. Providing protection, conservation of moisture and on sunny days in winter (it is still winter) considerable warmth. Also the light available outside is 10,000 times stronger than any light you could manufacture with grow lights going for 14 hours a day.
Set the jugs outside (no caps). Check on them every so often to see if they need moisture--I use a spray bottle to add water inside the top opening. I also spy into the opening to see if anything is happening. Riley finds this mystifying.
The next round of jug planting will take place near the end of March. For more tender seedlings and perhaps a second try at the onion seeds if the first has failed. I will attempt to grow marigolds, zinnias and bachelor buttons in the jugs. I have tons of flower seed packets from the end of season grab bag at work. And I think annual flowers make a garden very jolly.
Once the seeds germinate and little green leaves appear (when one peeks into the spout) it's time to peel off the duct tape and open up the little greenhouses. Just for the daytime. Close them up again as the sun goes down. One little piece of tape should hold the top half of the jug in place.
Later pictures from this website show all the jugs with their top half flipped open and the little seedlings flourishing. By this time--the little plants can be transplanted to larger pots of go into the garden if the soil has thawed. It certainly saves on cluttering up the house with grow lights etc.
I hope to have photos of my own robust production of seedlings by April. We'll see.
In a note on the bottles. G drinks quite a bit of orange juice and we already use the empty 89 ounce bottles to hold water to water plants on the front porch and in Winter in the upstairs winter plant storage area. So we have quite a few bottles on hand. I was going to try making the juice bottles into "greenhouses" but punching a starter hole for the scissors was too difficult (and a bit dangerous) and I wondered if the plastic of the bottles might be too brittle to cut successfully. Some of you might have better luck. Let me know if you find a way.