Ask the Master Gardener: Get a head start on spring by winter sowing seeds now

Winter sowing has become very popular in the past few years. It seems to work best with perennial seeds and those seeds that need to go through cold-stratification to break the seed coat.

Items needed for winter sowing of seeds.
Reusing a plastic container, like a milk jug or one for food takeout, with dampened potting mix inside, seeds can be started in these "mini-greenhouses" by setting the containers out of direct sunlight and right in the snowbank. <br/>
Contributed / Jackie Burkey

Dear Master Gardener: Can I start winter sowing now? How do you do it?

Answer: Winter sowing has become very popular in the past few years. It seems to work best with perennial seeds and those seeds that need to go through cold-stratification to break the seed coat. I’ve had luck with cool season vegetables like lettuce and spinach and seeds saved from some native perennials. If you try annual flowers, choose plants that have better cold tolerance like pansies or snapdragons.

Start by collecting plastic containers. Milk jugs work great — just slice most of the way around below the handle so you have a “hinged” lid. I prefer reusing bakery or takeout containers with clear lids that snap on. Poke holes in the bottom for drainage, as well as some holes in the lid to let some rain or snow in. Don’t forget a waterproof label! Then put a couple inches of dampened potting mix with no fertilizer in the bottom. Sprinkle your seeds on top, press them down slightly after sprinkling just a bit more potting mix on top. Snap the lid back on, or tape the milk jug closed with duct tape. Find a protected spot out of direct sunshine and set your creation in a snowbank! As long as you see some condensation inside there’s enough moisture. If not, dribble some water down the inside edges. When the seeds’ genes determine it’s time to sprout, they will. Once you see the second set of true leaves you can slowly move the containers to brighter sun, open the lids on nice days, and pop the tops back on if it gets too cold overnight. Keep the containers watered.

Plants may be transplanted directly into the garden with no hardening off period — they are already accustomed to sunshine and wind. You can also plant the small seedlings into individual pots if you want to let them mature with deeper roots and more vegetation.

Try winter sowing. It doesn’t take much time to put soil in a container you were going to recycle anyway, toss it in a snowbank, and get a head start on spring!


Dear Master Gardener: My yard is shaded by large, mature trees, but I would like to grow a flowering vine on my trellis if possible. I’ve tried Clematis and morning glory, but neither survived. Is there a flowering vine that will grow in a shady garden?

Answer: It depends on how shady the area is. Clematis and morning glory need full sun. The Clematis that are pink can tolerate more shade, but still need four hours of sunlight. Purple bell vine is an annual vine that will grow in part shade. It prefers morning sun and afternoon shade. It produces masses of bell-shaped, maroon-purple, pendant flowers that dangle from threadlike stems. It has lovely 2-inch, heart-shaped leaves that are edged in purple. It is fast growing. If you start it from seed, it takes about 16 weeks to begin blooming. Black-eyed Susan vine (Thunbergia alata) produces dainty, funnel-shaped flowers that vary in color from white to yellow to orange. It does not like intense heat and performs best in partial or light shade. The seeds can be started indoors 6-8 weeks before transplanting.

Dear Master Gardener: Should I pot up the calla lily rhizomes I am overwintering now?

Answer: It’s still too early. I usually start mine at the end of March. You may want to check on them and make sure none of them have soft spots or mold. If any are mushy or soft you should toss them out. Plant calla lily rhizomes one to 2 inches deep in a well-draining potting mix, water well, and place them in a warm location. Keep the potting mix moist, but not wet, or you will rot the rhizomes. Move the plants to a sunny location when foliage appears. Plant them outside when there is no danger of frost (I’d wait until the first week of June).

Dear Master Gardener: Plant tags and books say part shade, filtered shade, full shade, part sun, and full sun, but what does it actually mean?

Answer: It can be quite confusing indeed! Books and plant tags vary in the terminology they use to describe a plant’s light requirements. Choosing the right plants for the amount of light in your garden is very important for the success of your plants. Most sources agree that full sun is six or more hours of direct sunlight per day, partial sun is four to six hours, partial shade is two to four hours, and shade is less than two hours. With that said, you may also come across various terms for shade. Light shade is usually defined as receiving three to five hours of direct sunlight per day. Filtered shade is an area under tree canopies that seems shaded, but receives shafts of sunlight throughout the day. Dense shade receives no sunlight.

Dear Master Gardener: I have noticed little bugs flying around my plants that look like fruit flies. How do I get rid of them and will they harm my plants?

Answer: It sounds like fungus gnats. If you shake your plant or stir up the soil, you may see a flurry of insect activity. Fungus gnats are usually associated with over-watered houseplants or houseplants that are growing in potting soil that is high in organic matter. They are pesky but do not usually harm plants. Reducing the moisture in your soil should be your first step in combating the fungus gnat problem. Over-watering is one of the biggest mistakes people make with their houseplants. Allow the surface of the soil to dry out between watering sessions, but do not let your plant wilt.


According to the University of Minnesota entomology department, the only effective product for treating fungus gnat larvae in the soil is Bt h14 (for example, Knock-Out Gnats). However, this product does not kill adult fungus gnats. To reduce the number of adult fungus gnats you can place yellow sticky cards in the pots. Look for the insecticide and sticky traps in garden centers or online.

You may get your garden questions answered by calling the new Master Gardener Help Line at 218-824-1068 and leaving a message. A Master Gardener will return your call. Or, emailing me at and I will answer you in the column if space allows.

University of Minnesota Extension Master Gardeners are trained and certified volunteers for the University of Minnesota Extension. Information given in this column is based on university research.

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