Sowing Perennials in Recyclables

For those who just can’t wait to get outdoors in the Spring, Winter seed sowing is just the thing! You will find that start-up is easy and requires few supplies and moderate level of activity. During the Winter, there is a low level of activity. In the Spring there will a higher level of activity.

The idea of Winter sown seeds is simple: we are trying to imitate Nature while controlling where the seeds will grow. You will learn over time which seeds do best freshly sown, and which don’t seem to mind when they are planted. There is information online and available locally from garden groups, such as the Alaska Rock Garden Society, the Native Plant Society, your local garden club etc.

Sowing Schedule and Methods

There are a couple of times and ways to sow seeds in Spring or Fall. One way is to use milk jugs or other plastic recyclables. These will be left outdoors. Or just use a standard seed flat. You can sow seeds in the Fall to imitate Nature’s method, called stratification, or sow outdoors in Spring before the soil warms.

The Milk Jug Method

For the milk jug method, cut a hole to the side of the handle. I use a razor knife. Then use a scissors to cut the jug in half, leaving the handle attached as a hinge. You should add holes for drainage. I use a drill for that. Add soil to just below the level of the bottom half of the jug, moisten and seed according to directions. Tip the top, hinged half of the jug closed and tape it shut. Forget about it for a while, but peek inside now and then. Keep moist in Spring.  I’ve had good results using any of the produce or deli containers from the grocery store. Old seed flats work well for me. I use flats with holes and/or old cracked flats that can nest inside another one, which allows for drainage. Fruit and other produce containers may have holes already, such as those used for strawberries and raspberries. Or you can drill or cut holes for drainage.

Laisser Les Conteneurs À L’air Libre

I do not cover my flats. Leave the lid off so rain and snow will go in. Just leave outside and make sure they have snow cover until Spring. Yes, you may get some uninvited visitors (weed seeds) but accept what the universe provides!

Soil Preparation

Any used container soil is fine as it will be outdoors and will not harbor any pests. Adding sand or grit may be useful to increase drainage. Moisten soil to get things started. Add soil at least 2 inches deep in container, with “headroom” for seedling growth, as in seed flat with clear lid, clear deli tubs, “clamshell” deli container, etc.

Smaller containers dry out sooner so remember to keep an eye on your seeds as the snow melts. Try bringing a tray that has been given the outdoor treatment into a cool greenhouse (40-50 degrees) in Spring to get a month or two jump start. This technique works for many seeds.

Sowing Tips

For seeding I like to sow thinly on the surface on the soil so you don’t need to thin much later. Small seeds can be mixed with sand for more even distribution.

Some seeds require light for germination, and some require darkness. In general, smaller seeds should just be pressed onto the surface of the soil for good seed-to-soil contact. Larger seeds can be pushed in with a pencil (eraser end) to a depth of 1-2 times their thickness. A good book on the subject is The New Seed Starters Handbook by Nancy Bubel. Cover seeds thinly with sand, grit or a light soil mix. You will discover in time which methods work best for you. Primroses seem to do well on a grit surface, for example.

Labeling and Patience

After sowing, tape on lid, or not, and add a label. Write on the recycled deli containers with a permanent marker. You can add a traditional white plant label for the inside too. Use pencil or a special label marker. With seed flats, put label between the nested flats so they don’t blow away.

Some seeds may take time so don’t be in a hurry. If sowing mixed seeds in one container, you may have different germination requirements, such as planting depth, light/no light, temperature, etc. but it’s worth a try. View Winter seed sowing as a fun science fair project.