You could just plant the seeds in the autumn and leave the outside over winter. They're totally hardy shrubs which don't need to be started indoors under lights. Once they're germinated the temperature doesn't matter.

Well, I had a whole tray of tiny seedlings fall over at 80degF under high output T5 fluorescent lights hung about 4' above, and the only reason I could come up with was the temp above 77degF. Can you think of a reason?

There are 3 reasons I don't want to start them outside. 1) I have a feeling that it would require much more seed (it's a long property boundary.) 2) the location is a wild edge. I fear rototilling the soil will only stir up more seeds and that there will be too much competition. 3) I live in zone 4a. While the seeds I have are from a reputable seller who advertises them as hardy enough to grow here, I want to give them the best chance.

You had T5 fluorescents hung four FEET above the plants?? They wouldn't have been getting almost any usable light at all! Did they etiolate?

The seedlings did not look weak or discolored. They all just started falling over... Are you suggesting I try a sunnier and cooled location?

FYI, These are 8 bulb fixtures with good reflectors, and they get quite hot underneath. I have found that 4' is close enough to start a bunch of stuff that requires shade or a shadier location in the first year. And, the closest I can get them to most of the plants I'm growing is 24" (including full sun plants). Closer and they start yellowing, losing leaves, and dying. (Even at that distance the temp underneath is 87-88degF.)

Sorry to say but not a chance in the world of Pyracantha coccinea surviving outside in a zone 4 climate!! Maybe a zone 5 for the hardiest types and with some protection.

gardengal48, I got them from F. W. Schumacher, so I am willing to give it a go.

You have something else going wrong. 2 feet from a T5HO fixture should NOT stress any full sun plants the way you are describing. They are not particularly powerful lights, and the heat output is not significant.

Well, that is by far the lowest zone rating I have ever seen for this plant....and in most cases by a two full zones. It is typically rated winter hardy to only zone 6 with a few cultivars possibly enduring a zone 5 in a protected siting. Any by very well-respected sources.

Seems like a lot of work to go through for something that is highly unlikely to survive........

illsstep, What else do you think might be going on?

And, FYI, it seems to stress a lot of them including Gleditsia, poppies, pines, oaks, delphiniums (which I germinate 4 feet from the light and leave for a while; germinate rhododendrons at that distance, too...) It does not stress roses or Thuja. As plants get older, they can deal with closer lights. Next time I will set it up so that they can be under lower lights, but right now it would be hard to manage because it is a higgledy-piggledy-hodge podge...

gardengal48, So many spiny and thorned hedge plants (that I actually like and don't require a lot of work) are illegal or frowned upon in my area that I will go so far as to select for the hardiness if I have to!

illsstep, You may be onto something with the humidity! The "greenhouse" is about 10% humidity all winter. It was practically open to the outside when I caulked and insulated it, but the humidity is still very low all winter. Maybe I'll get a humidifier in the fall...

The point I was trying to make is that you cannot make the plant hardier than it is or is known to be. Have you ever seen it growing in your area? I find the seed company's data extremely suspect. The Missouri Botanical Garden reports it is not reliably hardy in St Louis (zone 6a) and the University of Connecticut lists as a liability "lack of solid cold hardiness and winterburn". It is also highly prone to fireblight.

I really like the shrub so have no prejudice against it. I just have very strong doubts it will survive for you in zone 4.

gardengal48, There are breeding programs all over the world selecting hardier varieties of plants. I have been reading much about a large rhododendron program recently Breeding Cold-Hardy Rhododendrons. The University of Minnesota bred the Northern Lights series of azaleas... I am going to try my hand at several types of plants typically hardy to only zone 5... That said, it may be only a handful out of a hundred that will even survive and go to seed. I have about a quarter pound of P. coccinea seeds, and am hoping to get a hundred hardy plants to line the border :)

There is a big difference between breeding or hybridizing for increased cold tolerance and just planting a bunch of the same seeds and hoping some will be radically more hardy than the others :-) I appreciate your intent but your expectations are unrealistic given your methodology.

gardengal48, I don't know what kind of science background you have, but the methodology is quite sound.

I have purchased a quarter pound of (30,000) seeds collected from (presumably) the hardiest plants. (F. W. Schumacher being a reputable company, I expect that they did that--otherwise I expect that they wouldn't have advertised them as being the hardiest ever P. coccinea seeds.)

I assume that the seeds were open-pollinated and that their parents were open pollinated. In this scenario (assuming the cheapest easiest way to produce seeds) I am starting with 30,000 genetically diverse seeds harvested from the hardiest P. coccinea. (This isn't a bunch of clones I bought at a nursery hoping that one clone would be hardier than another!)

If even 1% of the germinated seeds is as advertised then (assuming just a 50% germination rate because it's easy) that should yield 150 plants. (At 100 plants, I am setting the bar extremely low--basically assuming that this reputable retailer is stretching the truth.) ...But, even if there is only a pair then I will be happy because (hopefully) I will be able to hybridize them and grow many hardy plants. (In the meantime, I will just grow rosa rugosa or something instead.)

P.S. For the sake of simplicity, I made it out as if I got all the seed from F.W. Schumacher. I got about half from them and half from another source. Ideally, this will mean that I have seeds that were open pollinated in different places with different parents. The hope there is that it would up the genetic diversity in my pool.

Without commenting on the likelihood of your "breeding program" working as you think it will, I have to ask - what sort of success have you had so far growing those seeds to a size that can be reliably planted out? You are talking about growing seedling populations on a huge scale, yet from the tidbits you've offered so far, you really don't seem to have a firm grasp of the variables you need to control to get them up and going. I don't mean to be harsh, but your success rate may be far, far below what you are estimating, at least with your current setup.

Right now, my success with Pyracantha past germination is zero. But, as far as my plants go generally, I don't think your characterization is accurate. While you have identified a potential issue for which I thanked you (and by the way humidity outdoors will be about 10% or less where I am), I have had many more successes in my first year than failures. These include Pinus longaeva, Pinus nigra 'Austriaca', Pinus cembra, Pinus sibirica (or cembra 'Sibirica'), Picea koreana, Rosa rugosa, Thuja occidentalis, Gleditsia triacanthos, Papaver somniferum, Delphinium 'Cliveden Beauty' (which recently bloomed under the lights you describe as being way too far away), Morus alba, Morus rubra, Ilex verticillata, Malus baccata 'Mandschurica', and Quercus robur. Some of these I have in such large numbers growing at such a high rate that I literally have no room to repot anymore and am hoping that they hang on long enough to move outside (it still gets down below freezing at night, and last year I had no luck moving anything outside early). The Morus alba 'Tatarica' that I've been potting up is so big that it is almost at the ceiling!

When I suggested outdoor sowing we hadn't been told this was zone 4. To me it's a bone hardy shrub and it never occurred to me it might not be. It's daft to say it can't cope over 77f as even here it will encounter such temps in summer. Could you be getting confused with the fact that after cold stratification newly sown seed (not seedlings) shouldn't be exposed to high temperatures to avoid secondary dormancy? Did you do the 3 months cold stratification?

Btw when I said to sow outdoors I didn't mean direct in the ground. Hardy trees and shrubs can be started in pots, protected from animals and overwintered outside. It's a common method for hardy species.

floral_uk z.8/9 SW UK, I did the cold stratification. Maybe I am confusing the secondary dormancy issue... I had dozens of little seedlings about an inch tall in a 7" X 9" container about 4" deep. They were near a shaded window with the T5 lights overhead. They were green and seemed happy. Then one day, they all started falling over. The same thing is happening right now with my Potentilla fruticosa. I have moved the potentilla to a location that gets no direct light in the living room because I read an article indicating that they like shade in their first year.

...I just assumed you meant in the ground, sorry. Yes, I intend to start sowing in protected pots this year. I have a scheme in mind to sow in pots in a small paddock then sink the pots into the ground over winter. I might put up some burlap, too. Or, I might just see what survives. The plants should be hardy! :)

P fruticosa (now Dasiphora) will be miserable in the shade of a home. I don't know where that shade information comes from but it must be talking about outdoors. Almost anywhere inside is going to be too dark for them.

For both species seedling plants won't be as impressive as named cultivars but all you can do is wait and see how they turn out.