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Wintersowing (WS)
(Author: Lynn Watson, reformatted from original)
“Sun, Jan 30, 11 at 2:55—Well, I finally got started today! It’s dead cold outside! You want me to plant?
That's why we sow in the dead of winter. The tomatoes started by winter sowing were just as good as any
other transplant , will be a little later vs .started indoors, but they will be much healthier plants! Once
hardened off and planted out, they catch up quickly.”
“I only WS one container as an experiment. I wished I'd WS a dozen because every seed germinated.”
“I've sown about 600 containers now. It'll work. It's going to be 65 here for the next few days. I start
wintersowing after New Year's Day and kind of do it successively thru the end of January, first of
February, so that my perennial seed gets sufficient stratification time.
Pages to further info on WS:
Google: Wintersowing
•
Tom Clothier / tomclothier.hort.net
I rely heavily on Tom Clothier's database because it tells me what at what temps a seed
sprouts, and whether it needs cold stratification. The first seeds to be sown are the ones that
sprout at coolest temps and require longer colder stratification.
•
Canadian Winter Sowing - GardenWeb
•
www.wintersown.org/wseo1/DataBase.html
www.wintersown.org/wseo1/Seed_Lists.html
(200 free seeds packs for organizations)
•
davesgarden.com/community/forums/f/coldsow/
•
www.lakehousecreations.com/winter_sowing.htm
forums.gardenweb.com/forums/canwtrsow/
Purchase/Recycle (Home, friends, transfer station dumpsters)
SEEDS: The theory of WS-ing was based on the idea of reseeds. A reseed: any plant (regardless of what
type) all ready reseeds in your area naturally. The tomatoes started by winter sowing were just as good as
any other transplant . They will be a little later vs. started indoors, but they will be much healthier plants!
Once hardened off and planted out, they catch up quickly.
SEEDS TO BUY/KEEP: WS: perennials, large seeds, plants that will have a stalk. There are basic
packages of seed at the dollar store-On any seed package, check year packed for planting. Seed stays
viable up to 3-4 years if kept cool, dry and dark- the larger the seed ( pea/bean etc.) the longer it stays
viable. *Agastache rupestris/sunset hyssop- * Alcea rosea/dwarf hollyhock * allium karataviense-ivory
queen *Alyssum, * Aquilegia, Firecracker , * Aquilegia, Chocolate Soldier, *Crocosmia, Lucifer ,
*Dianthus barbatus, Black Magic , *Dianthus barbatus, Sooty Lettuce, *Jericho Poppy, * Oase (peony)
Poppy, *Red Ruffles (peony) *Snapdragon, Scarlet *Giant Snapdragon, Frosted Sunset Bonnie *
Gauralindheimeri/wandflower * Platycodon grandiflora/balloon flower * Lupine *Lychnis
chalcedonica/Maltese cross *Rudbeckia hirta/ gloriosa daisy
MORE TO WS: Anise hyssop*
Butterfly bush-white and purple prince *Clematis macropetala-Jan Lindmark * Clematis-ville de lyon
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and rouge cardinale *Columbine-red *Coneflower-pink glade *Foxglove-yellow *Gaillardia-burgundy
and goblin * Hollyhock-yellow and red *Hosta-from big daddy* Llychnis flos cuculi-ragged robin*
Verbascum-milkshake *Veronicastrum-alba More seeds for WS listed on back of page
SOIL: Don't use anything labeled "GARDEN soil". You're looking for a light weight mix, not a heavy
one. Germination Mix #3-Ericksons-cubic feet (save in bag or trash can year to year). A good quality
soilless germination mix will reward you because it makes a difference in moisture retention and adequate
drainage. I hope you choose not to use junk.
STIFF STEAK KNIFE: for cutting plastic drain holes-Thrift store
CONTAINERS: Keep in mind is whether the container holds enough growing mix for the roots ,and
headroom for the sprouts. WS sprouts have incredible roots. Your containers can dry out on a warm
spring day before you know what hit you. It is for this reason that I lean toward milk jugs and pop bottles.
I can put deeper potting mix in them.
Plastic Jugs: Translucent enough to see your finger through the plastic from the inside. The color
of the container counts towards letting needed light in for your seedlings. Rule of thumb : "If you
are using a container made with tinted plastic it is easy to tell if the plastic is too dark and will not
let in sufficient light. Can you see your thumb through the plastic? Then you can use it. The color
of the container counts towards letting needed light in for your seedlings. I cooked a couple of
plants in clear bottles, so I know the cloudy milk jug works best for me. 2L pop bottles: Clear or
green High dome clam shell deli packs. The growing mix in smaller containers tends to dry out
quicker than the milk jugs. Ultimate in domes. Get two of the largest dome-type window well
covers and bolt them together. You end up with about a 3x4 mini greenhouse! They are the
ultimate in winter sowing covers. (I have not used these).
Preparation: Proper ventilation and drainage. You must have holes in the tops of your containers,
whatever you choose, and you must have adequate drainage. If you choose milk jugs or pop
bottles, toss the screw on cap from the beginning. (Or save them for discreet pot feet under house
plants.)
Drainage Hole: General purpose: You'll want enough drainage holes you can punch or cut more
if needed then to let out excess water if you find it. (That is hard when it is full of dirt.) There
should be sufficient holes to allow rain/snow melt to drain out of the container so seeds don't rot.
The soil should be able to retain sufficient water to allow the seeds to germinate.
Milk Jugs: Punch holes in jug bottom in four corners where plastic thickest. At least 4 that you
can ‘stick your thumb through’ 1’x1’ Cut where plastic is thickest the lowest point in the bottom,
where water would collect. Put four slashes in the very bottom. 2L Soda /clamshell - little finger
size holes should be in the top and the bottom.
Cutting for access:
Jugs: Milk/water jugs: cut with only a small hinge left; cut with the U opening (prefer this
so the top can fill better with leaves). Cut top half almost off. Prefer the U to FLIP up. We
are not actually cutting a U as it appears typewritten because the bottom of the U is a
straight cut across on top.. Cut all the way around the milk jug except for the handle part.
You can punch 2 holes with a heated ice pick opposite the handle and about one-half inch
from the cut, one in the top half and one in the bottom. After planting, use wire bread ties
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to push through each hole and secure the two parts together. You can still lift the jugs by
the handle if you need to move them. Soda Bottles: bottles are cut about 2/3 for the bottom
portion and 1/3 for the top. bottle. I cut a vertical slit (about 3") up the side of the top
portion of the soda bottle, so you can fold it a bit to fit inside the bottom portion.
SOIL PREP: Use plenty of soilless mix.. Have drainage holes and deep enough soil for roots and to
retain moisture.
Mix soilless mix in dishpan, inside gallon baggy, or within the purchase bag (like making a dough
ball in flour sack) or moisten growing medium in jug bottom until water drains out through holes .
Use WARM water ( better absorbtion) moisten soil less mix to sponge wet. I have a large
plastic storage tub into which I pour lots of #3 mix. Then I add HOT water mixing with my small
garden fork until it is like pudding. It needs to be mixed well or it will have dry spots. This makes
lots of dampened mix and allows me to sow many containers assembly line fashion. Let mix cool
off before using to plant.
Depth of potting mix: Don't scrimp here either-4 inches is the minimum recommended amount,
again for moisture retention. For spring sowing, or warm weather annuals, this is even more
important. Fill jug bottom with growers mix. Water should be running out of the bottom. Fill your
containers with at least 3-4" of the mix (after watering). Fill the container to the edge of the U's
bottom . Press down soil- it will compact a bit .Push the bottom of the U in after I wet Let it drain
until its not running out the bottom.
PLANTING: Too late? No, no, no! Most of us will be planting more seeds periodically through out
winter till March. So no it is not too late!!
Large leaved seedlings (squash, cukes, etc. 1 per soda bottle.) Milk Jug: Seed size: Med -3. Small - 4.
Small seed like lettuce and carrots: Place or sprinkle seeds over moistened growing medium . Cover seed
or not as needed. The seeds will be sucked down in the soil jug drains. Many fine seeds will not germinate
if not exposed to light.. Water with a fine spray from a spray bottle. - it should be running out the
bottom as fast as is introduced through the top so it doesn't stay soggy and the seeds are floating on top of
the water. Labels. use pieces of old plastic mini blinds for my labels Venetian blind markers inside
container.-Grease pencil. Condensation and wear will cause the label to fade otherwise. Remove tops.
(Optional)Adequate ventilation allows warm air to escape, sufficient drainage allows excess moisture to
flow away .
Seed timing
I'd treat the stocks and cleome as tender and wait until March or April to start. I have lost a
number of annuals because of my winter sowing enthusiasm. The good news is, it is easy to plant
more . Check recommendations on the back sheet of this handout.
I wintersow tender annuals and half hardy annuals the first of March to mid-March. I have to keep
a close eye on my containers then so they don't bake the new sprouts. They will be a little later vs.
started indoors, but they will be much healthier plants!
Many herbs and tender annual seeds should be SS-spring sown in March-April. SI= Sow Inside
If temps are much below freezing at night, you want to stick with cold hardy vegetables, herbs,
and flowers. For example, the chives, carrots, and cilantro would be fine now, I started tomatoes
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by winter sowing one year and they were just as good as any other transplant but they were a little
later than those grown under lights.
I wintersow more flowers than veggies, but there are some early veggies that I start in jugs, like
broccoli and lettuce.
Transfer to small containers until I am ready to put it in the ground. That way the entire root ball
gets planted so I don't disturb the roots at that planting.
Warm season veggies, such as melons, cukes, or tomatoes, I'd wait until closer to your last frost
date. Otherwise, if you have a warm spell, they will germinate, when temps drop back =protection,
such as a row cover, or risk losing your sprouts.
Small seeds don't have a big fuel reserve, plant at /just below the surface of the soil. Just enough
energy to get the root and the leaves up. Too deep and sprout can't get above soil.
Placement Outdoors
I do remove the tops eventually (at first it may just be during the day, replacing the tops if we have
a very cold night, especially with the half hardies and the tenders). I try to take tops off soon as
sprouts emerge if there is not a chance of frost. I leave them off if I am wearing light spring
jackets.
Access to hydrating rain and/or snow assures a supply of moisture to the seeds as they prepare to
germinate
North facing deck: shade in winter. More Spring-like= angle of the sun changes (and things have
germinated), move shade lovers closer to the house, leave the sun lovers in brighter light. Shade
lovers = shady side; --sun lovers = got more sun.
Containers in sun need to be checked more often and may need to be watered.
Light mist condensation= enough moisture in container. As temps rise in spring, check the
containers often, see if the soil looks dry: mist top, or place container in a shallow tub of water: it
absorbs from bottom. Avoid heavy watering from the top, seeds could wash out the drainage
holes.
Ring annual containers with perennial containers= additional insulation, for annuals protected by
this additional warmth, Throw a blanket or row cover if it looks like the temps are dipping below
35 (if annuals have sprouted).
Put Wintersown containers in a safe place where, skunks, coons and such night can't find them and
tear into them. (We surround with a length of snow fence at Tech.) Keep jugs from blowing
around: Set gallon jugs around half-gallons/two liter bottles to hold the taller ones with smaller
bases. Run a wooden or bamboo stake through the handles and they'll stay together. You can also
surround with bricks or blocks.
Transplant Timing- Check Ground Temperature
If the plant leaves are bent up against the side of the milk jug, they may rot. I this size plant into
small containers until I am ready to put it in the ground. Entire root ball planted - I don't disturb
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the roots. At Tech we just planted the whole mass of dirt and roots into the ground. They slid out
very nicely.
If the plants are growing too fast, and the ground temperature is not warm enough to set them out,
put in the containers in the shade to slow growth. Traditionally Winter Sowing suggests that you
don't transplant until the seedling has its first set of true leaves (and that you do so as soon as they
do.) This is sage advice for perennials and a lot of flowering annuals.
Contact with soil is helpful for residual bottom heat, be sure the planted container is not in a low
place that collects water and connects drainage. Dig down into the snow bank a bit to keep jugs
steady. Check as the snow melts to keep upright.
Remove caps, if not already off, at the temperature you are wearing a light jacket outside.
Check to be sure water is mist condensing on the inside. If not-use hose or water container to pour
water in the tops—it will drain right through.
As spring approaches, do not plant out starts early unless plants can be put in cold soil or under a
milk carton mini-greehouse/wall of water/plastic hoop house. For hot weather plants like squash
and cucumbers be sure the soil is warm enough! Weather is warm enough if you can stand out in
the garden in bare feet and your ankles don’t turn blue—you are comfortable.