Winter Sow-Bag Care

Sow-Bag Care:

Place the bags OUTSIDE on a shelf in the sun. You can put bags close together, even touching, but not packed in too much. Keep your bags/seeds moist on the inside. You can tell if the bags have enough moisture if you are able to see condensation on the inside. They should look like wet, little steamy green houses! Here are some watering suggestions:

• Place the bags in a tray, add water to the tray, and allow the soil to wick up water from below into the soil and to the seeds. Just make sure that you have given them enough water to be able for all the bags to get adequate water.

• Alternatively, using a watering can with a long, slender spout, pour water down the inside-side of the bag. NOT directly all over the soil but down the plastic so that the soil stays moistened but the seeds don’t battered by the pouring stream.

Now leave them alone, in the sun, snow and wind and just make sure they are moist. Come springtime, the seeds will sprout and grow. In the case of a very warm winter, you may want to give them some covering once in a while to remind them that it is still winter. Once the seeds have germinated and sprouted in the spring, start folding the tops of the bags down to allow airflow to harden off the seeds. The little seedlings will have been acclimated to the cold and sun and temperature swings - but not to wind. Exposure to wind helps thicken the stems so you don’t grow spindly, weak stemmed plants.

It will be time to put these beauties in the ground once the threat of the first frost has passed - typically around Mother’s day in Colorado - but keep an eye on weather reports. Plant them amongst other plants so that they have some protection. If you are starting a garden from scratch, you may need to find a way to create a bit of artificial shade - like with a light shade cloth supported by sticks or an upside down clothes basket. Just don’t let them fry in the sun or alternatively freeze when we get an unusual frost. If a frost happens, I recommend covering the small plants with upside down plant pots to keep frost off their leaves and stems. You may uncover them once the risk of frost passes. Snow itself will not harm the plants, just freezing temps will.

Follow basic care for newly planted Native Plants over the next couple of years! Have fun!

What are sow-bags?

Sow-bags are small, reusable bags that are used to make germinating seeds much easier during the cold winter - like a mini greenhouse! Sow-bags are easy to prepare, and can be a fun, quick activity to give back to the planet (and you can give them as gifts)!

Facts about this type of sowing:

• You must use only potting mix (and I prefer soil that does not have added fertilizers, pesticides or other chemicals).

• Don’t use seed starting soil mix as the growing medium in the sow-bag, because it does not hold water well enough and it is not nutritious enough to support the growth of the seedling once it sprouts. Also, avoid soil directly from the garden as it is very heavy and typically contains the wrong amount clay and/or sand for sow-bag germination.

• You will have to use gallon-sized plastic bags in order to maintain enough moisture and soil to support the seedling roots. Smaller plastic bags won’t work.

• You can expect somewhere between 70-80% germination rate. In other words, not all seeds want to germinate every year. In nature it has an even lower rate of germination.

  • So, not every seed in every bag will sprout. Some bags may not sprout at all this year. It is usually not because you did something wrong, but because that species just did not want to germinate under these conditions, this year.

• Once the bag is set up you will have to keep an eye on it to keep it moist or the seeds won’t germinate. Moist does not mean swamped with water. Too much water and the seeds will rot. Good drainage is important - so if the bags are draining slowly, cut the holes bigger.

Notes:

• A way to get your winter sowing home without soaking your car:

  • Plastic boxes or trays or some other impermeable container would be best, as the bags will be dripping wet.

• You can start making winter sow-bags after the solstice in December, and all the way up to the equinox.

  • Bags started later in the winter and very early spring will still germinate, but the challenge is that you need to get them in the ground before it gets too hot.

• You will find that some of the Native plants, which are thought not to flower in the first year, do indeed flower during year one.

  • For example, several of us had great luck with Erigeron speciosus (Fleebane).

• Some species’ seeds may require lots of prep before putting them in sow-bags. For example; heat stratification, scarification, or dark and cold temperatures. If you are experienced with these types of seed treatments or want to experiment with more challenging species, by all means do so and put them in the sow-bags after you have applied the treatments.

  • Note: these are physical treatments or adding simple things like a bit of natural soap, but I am not referring to chemical treatments like chemical fertilizers.

  • The USDA often has great instructions on treatment of difficult to germinate species.

  • I personally am going to do several species that require pretreatment before putting them out into the seed bags because I am hoping to introduce some difficult species that are difficult to find in nurseries because they are so hard to germinate. However, the treatment of these seeds is beyond the scope of this workshop.