ELi ON EARTH: Snow Sowing Time in EL

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Monday, February 2, 2015, 12:34 am
By: 
Aron Sousa

Image: The author sowing seeds the day before the big snow.

If you are tired of winter and cannot make the trip south to warmer climes, you can still begin some spring activities right here in East Lansing. It may not be warm outside, but there are some seeds that do well planted in the snow. Snow planting is as simple as putting the seeds in the snow where you would otherwise plant them in the dirt.

When the snow melts, the seeds will be left on the soil. In the freezing and thawing cycles of spring, the dirt will expand and contract and heave up to envelop the seeds. The frost heave that cracks our sidewalks and creates our potholes will bury your seeds for you.

You do have to pick your seeds for snow planting somewhat carefully. It is best to pick seeds that need some time in the cold to germinate. In a previous ELi on Earth we covered the process of starting seeds inside, in trays. In that article, we covered some plants from cold climates that need a period of cold to break their seeds’ dormancy period.

Seeds contain a plant’s embryo, and a seed’s dormancy period increases the chances that the embryo develops at the best time for germination.

Seed dormancy is complicated. After ripening and drying, seeds can sit dormant for a long time until the conditions are right for the seed to germinate. At least one two-thousand-year-old date palm seed germinated after it was found near the Dead Sea. While a seed dormancy of two millennia is beyond the needs of this gardener, the ability to store seeds for planting the next year or in many years is a great benefit of seed dormancy.

Scientifically, it has been complicated to study seed dormancy. It can be difficult to tell if seeds are not germinating because the right conditions are not present or because the seeds are remaining dormant due to chemical and mechanical features of the seed itself.

There are several mechanisms that can contribute to dormancy. Generally, seeds have a hormone, abscisic acid, that inhibits germination. In seeds used to study germination, abscisic acid has been shown to have a role in controlling the action of hundreds of genes in the seed. In these studies, all of the seeds’ requirements for water, light, and temperature, etc., are met, but the seeds still will not germinate when abscisic acid is present in the seed. Under the same conditions without abscisic acid, the seed germinates. So this tells us that abscisic acid inhibits germination.

Interestingly, the abscisic acid has to be produced by the seed itself. The mother plant does not produce the abscisic acid, and you cannot spray abscisic acid on a seed to stop or inhibit germination. To inhibit germination, the acid has to come from the seed.

How seeds regulate their levels of abscisic acid is not completely understood. Like hormone systems in animals (including people), seed hormones are complicated systems with multiple hormones interacting with each other to modulate physiology.

For some seeds, specific conditions have to be met for the abscisic acid levels to be low enough to allow germination. Usually the seed coat has to soften or be removed. Fire, water, cooling or freezing, and digestive juices of animals can all soften or remove the seed coat.

Even after all the conditions are right, it can take time for the abscisic acid to be destroyed or wash away. The time requirement may prevent seeds from germinating after an unseasonable bit of weather or allow time for seeds to disperse before germinating.

East Lansing gardeners do not need to know about abscisic acid to plant seeds in the snow, but all gardeners have to meet the needs of their seeds if they are going to grow plants.

Snow sowing works best for plants that grow from the seeds of last year’s plants. Gardeners refer to these plants as “self-sowing”. Below are some pictures of self-sowing plants in the author’s garden: Allium (onion), Rudbeckia and Echinacea (cone flowers) and Asclepias (milkweed). The author’s gardening aesthetic might be generously described as “modified meadow.” This style works well for the inexact system of snow sowing.

Here you see a cone flower self-seeding and a milkweed self-seeding in the author's front yard. (Article continues after photos.)

Chives (an Allium), beets, and Bloomsdale Spinach all are classic choices for snow sowing. This year the author is also trying poppies (photo just below), and since he has never really been successful with poppies, there is little emotional risk in that endeavor. (Article continues after photo.)

There are a few risks to snow sowing. A rapid thaw and flooding can wash your seeds somewhere you do not want them, for example, into your neighbor’s yard or the sewer system. A more useful, but still unwanted, outcome is that rodents of all sizes and birds may see your planted seeds as food, which they are.

Still, the time is right for snow sowing in East Lansing. You can tell, because there’s snow.

 

Image below: A pair of cardinals in the author's backyard, being fed purposefully with safflower seed. Sometimes they eat seed not intended for them.

 

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