Re: Learning seed propagation...

Oh my! Thank you Marge! This is like an internet gardening course, and so
very helpful. Particularly interesting are these ways to grow up and
winter over perennials in pots in a plunge bed or frame....

Marge Talt wrote:

> Well, Allan, when I used to grow veggies and a lot of annuals, I used
> to start them in  pure vermiculite and in flats or whatever I had
> handy.  Worked fine, since they were pricked out at first true leaves
> and potted on.
>
> Now, I tend to sow in 3.5 inch pots because smaller pots or flats of
> tiny compartments tend to dry out too quickly on me.
>
> I use Pro-Mix for seeding with a top coat of granite grit about 1/4
> inch - sometimes a bit more thick.  There are pros and cons with peat
> based media like Pro-Mix, but at least it isn't full of weed seeds:-)
>  Peat tends to break down after a season and can remain soggy if
> overwatered.  I will add additional grit or even perlite (tho' I am
> not fond of it) sometimes for additional drainage.

Outside today in the sun, even the pro-mix I used for germinating seed
wants to dry out fast. The vermiculite would separate seedlings easier
I'll bet, but might dry out terribly fast in the sun.  I'll use some
shading cloth over the frame real soon I think where I have my seeds and
seedlings.  I'll have to try the granite grit too.

> I soak most of the seed anymore with a drop of dishwashing
> liquid...seems to help.  Don't do this with dust fine seed nor with
> seed of the lily family or asters..but anything with reasonably sized
> seed.

Sure just worked great with some Morning Glory seeds. They're up and
growing in 5 days.

> I use tweezers with a curved end on them to pick up the seeds and
> place them in the pot, so I can space them at least an inch apart
> each way.  Some small seeds for bulbs that I know will not get large
> immediately are spaced a bit closer.  Generally end up with 6 to 9
> seeds per pot of most medium sized seed.
>
> For dust fine seed, I tap it out on top of the grit and water it in.
> If it germinates too heavily, I just pull out the excess so the
> remaining seedlings have enough space to grow.

I've been using a clear disposable drinking straw, but I have a little
tweezers with a magnifying glass attached I should try. Its made for
woodworkers to remove splinters (and I use it often for that purpose).

> Most perennial seed does not want high heat - much of it wants cold
> stratification or a warm/cold/warm period or oscillating temps...with
> germination at 60F to 68F - normal room temps.
>
> A lot of annual seed benefits from warm temps as the plants are
> basically of tropical origin.

I didn't do it right this year--I mixed some annuals and perennials in
the same flat and have a mixture of things in my cold frame, so it's
impossible to have it 60 for the perennials and 75-80 for the annuals.
But I'm getting the idea (the speadsheet actually helps a lot here) to
group like requirements together. Perhaps I should just do mostly seeds
with like requirements in a year in the cold frame....

> Once seedlings germinate, most perennials benefit from cool growing
> temperatures - there are exceptions, but you get stronger plants,
> although they grow more slowly...that is actually good for them.
>
> The trick with perennials is to learn how the plant would germinate
> and grow in nature.  Is it a plant whose seed matures in spring,
> summer or late summer-fall? Try to sow the seed at the same time it
> would be sown naturally, if you can obtain it then.   Does it need a
> cold period?  For seeds needing cold stratification, the easiest way
> is to sow them and put the pots outside for the winter and let Mother
> Nature do the work.  You just have to make sure the pots don't dry
> out.  I cover flats of pots with screenwire tops that I make from
> rolls of screenwire - easy to do as you can cut it with scissors and
> tack it at the corners with fine wire...keeps weed seeds, leaves,
> debris and critters out of the pots.

Well, I've heard this but I imagine these pots just froze solid when we
get a week of nights down to -10, and -20 F. But, you must have to bury
them in a foot of mulch here to even out the temp. swings, prevent
drying, sudden or repeat thaws... Trouble is, here, our weather is so
variable. We've been getting thaws to 40 F in Jan or Feb frequently.  Had
a week of  60's in March, then 2 weeks of 20-30 and snow.

> Otherwise, damp paper towels in a zip-lock baggy in the fridge take
> up less space than pots and are easier (for me) to monitor than
> putting them in  a handful of damp peat.
>
> For plants wanting warm germination, I start them inside and (now I
> have it) put them in the greenhouse on a bench.  I don't cover my
> seedling pots as I can tell when they need water since the gravel
> turns white.  Have covered pots with plastic wrap and plastic domes,
> etc., but don't any more.  Think I used to do that mostly for the
> veggies and annuals.
>
> I prick out and transplant into individual pots, generally a 3.5 or
> 4" pot, but sometimes larger or deeper, depending on the plant, when
> they have true leaves or when I get to it:-)  If I am really tardy,
> have been known to simply plant the whole pot of seedlings in a much
> larger pot and let them grow on and then separate them later.  If you
> space your seeds in the seedpots, and transplant in a timely fashion,
> there isn't that much root damage.
>
> When I sow in flats (which I sometimes do for really large quantities
> of seed), I try to space evenly so I can simply cut out cubes with a
> sharp knife.  some roots are lost, but those within the individual
> cube are not damaged at all and the seedlings grow more roots
> quickly.

I've had big root mats of annual Salvia in a flat and just tore them
apart (carefully). The plants do seem to take a week or two to get over
it and its a bit traumatic for both of us!  Peat pellets look like an
interesting alternative. Easier to plant out too, quick and easy.

> I use my home made potting compost for potting on - basically a mix
> of screened compost, rotted woodchips, leaf mould and granite grit.
> Have not suffered any damping off problems with this - must be quite
> free draining as all potting compost should be.

This would save some money which would be helpful...

> I think air circulation is of prime importance with seedlings - run a
> small fan over them if you have lot of flats of them inside.  You
> have to monitor watering closely as the air stream will dry out pots
> quickly, but moving air is good for plants.

I've kind of noticed by plants under lights with nary a breath of wind
are quite "willowy" and lack sturdy stems. I'll have to try a fan on them
with the light timer.

> Wintering small pots over without a greenhouse is a challenge.  Your
> lovely cold frame should work.  I'd be inclined to fill the bottom
> with sand or mulch and plunge the pots in it and forget about them
> except to make sure they don't dry out.  With a cold frame, the trick
> is not letting it overheat.  If you cover it with old rugs, black
> plastic, old bedspreads, etc., it won't, as the sun won't penetrate,
> and the pots will winter over just fine in a dormant state.  Gets
> tricky as spring comes on but it's still frosty.  Pots will start
> into growth sooner in a frame than they would in the ground, so you
> have to open and close the frame so that they get light and plenty of
> ventilation but don't freeze, once they start into growth...

This is interesting... Grow the perennials in a pot the first year,
winter them in the frame, and set them out the following year.  I noticed
my frame was running 50 F warmer in full sun (90 when its 40 outside).
But at night it cools down to the outside temp, so I added the heater to
keep it above freezing in there.

> You can also make a temporary plunge bed from scrap lumber, concrete
> blocks or even bales of straw.  Fill it with mulch and plunge your
> pots and forget about them.  I find that this works best with at
> least 4" pots and larger is better, but I think Gene Bush plunges
> smaller pots - don't you, Gene?  Now, you're in zone 4 and that is
> considerably colder than where I am, but I still think it would work.
>  Dormant plants just need their roots protected, not their tops.

So, I imagine burying the potted perennials under a foot of mulch in
about November when the ground starts freezing and uncovering them as
soon as the mulch thaws in spring?   I guess that makes sense.... I'll
have to try this too!

> Unless you plan on putting tender annuals in that frame, I see no
> reason to heat it at all....or are you thinking of trying to start
> seeds of tender annuals in there?

Right now I'm trying to start tropical annuals (like Morning Glories,
marigolds, petunias), veggies (peppers, tomatoes, basil), perennials
(penstemon, lavender, delphiniums, etc) all in the same frame, and I see
one environment doesn't satisfy everything...  Yes, I imagined starting
the tender annuals in there and using the heater to keep the temp at 50
at night in say, March when we can get just about any weather from 0 F to
60, a foot of snow, etc.  But perennials like it cooler, as I think some
annuals (so I read) like snapdragons and asters. So in the future I'm
thinking I should try to group like requirements better. But don't you
think I'd need the heater to keep the temp above freezing? Perhaps not
with a blanket cover down to 20 F.

Well, this is just so helpful...  I feel like I have lots of new things
to try for the next several years.  I seem to really be getting hooked on
gardening!

-Allan

--
Allan Anderson
Jardinage, Copper and Cedar Garden Art
3701 East Minnehaha Parkway
Minneapolis, MN 55417
612-729-2285
http://www.visi.com/~response/jardinage.html


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