Winter-Sowing with DIY Milk Jug Greenhouses!
Where Upcycling and Gardening Meet!
With the cold and snow, it’s easy to think of February and March as a quiet time in the garden, but now is actually the perfect time to get a head start on planting, AKA winter-sowing. You don’t need any grow lights, just a sunny outdoor spot and some clear milk jugs to be transformed into mini greenhouses that can used to germinate seeds of hardy cool season plants like kale, broccoli, and peas, natives like milkweed and joe pyeweed, and flowering plants such as digitalis (foxglove). I love this method of starting seedlings––it’s simple, economical, and you get a lot of strong seedlings for fairly minimal effort! The first year I tried it I had great luck with kale, broccoli, and digitalis. This year I’m going to plant more natives––such as Joe Pye weed, Milkweed, and some peas since the birds always destroy my pea seedlings before they can get to any reasonable size!
Here are the basics…
What You Will Need
Clear Gallon Milk Jugs or other plastic containers––like big soda bottles––gallon sized are better but you can use liters if that’s all you can get. Plastic must be clear––this is a mini greenhouse essentially, so light needs to be able to get in.
Utility knife or other sharp knife to cut plastic jugs open.
Sharpies- to label what you have planted your mini greenhouses so you know what you’ve got!
Duct tape to keep the green houses shut once you’ve put in your soil and seeds.
Sharpie Don’t forget to label your mini greenhouses!
Soil such as a light-weight potting soil or seed starting mix.
Seeds... Glorious seeds!!
February Sowing: Spinach, Kale, Brussel Sprouts, Peas, Broccoli, Thyme, Sage, Oregano, Cilantro, Joe Pye weed, Milkweed, Foxglove, Columbine, Bachelor Buttons, larkspur
March Sowing: Lettuce, Bok Choy, Beets Carrots, Parsley, basil, Cosmos, Zinnia, Marigolds
April Sowing: Tomatoes!!
How To Do It
You can watch our videos here!
1.Punch holes in sides and bottoms of the milk jugs. Make sure there are plenty of holes––they are necessary for drainage and ventilation. I use a utility knife or exacto to punch the holes. Please be aware of where your supporting hand is when you are cutting holes!
2. Cut the jug in half––leaving a 1-inch piece connected so that you have a “hinge.”
3. Fill the bottom of the jug with soil to a depth of 2-3 inches.
4. Water soil to dampen it, you may wish to do this outside––or place jugs in a tray to collect the drainage water which will have soil. (Don’t do this in a sink or tub––the soil runoff will clog your drain!)
5. Plant your seeds in the soil, about 1 inch apart so that you can separate them when its time to transplant them into larger beds or pots. Smaller seeds do not need to be covered, but larger seeds like peas or morning glories can be covered with ½ inch of soil.
6. Label your jugs as you plant––or label them before you plant––just don’t forget, so you know what little seedlings you have! You can also include the date to check germination time.
7. Tape your mini greenhouse shut with a piece of duct tape, it does not need to be sealed all around, just taped shut.
8. Set it outside in a sunny spot that is protected from wind––both to keep the jugs from blowing around, and to help the soil warm up a little earlier!
9. Check in on it in 4 weeks, make sure the soil is still damp, see if you’ve got seedlings. On warmer days you can open the jugs to give the seedlings more air. February seedlings will be ready to transplant once they are starting to fill the container, usually in mid-May.
There are many great online resources for winter-sowing, my favorite is Kevin Lee Jacobs blog: a garden for the house.
He also has a great timeline list for what to winter-sow and when.
Enjoy, and good luck with your own winter-sowing!