Do you know which primrose you are trying? Varies by species.

In general for the hardy types, light, outdoors in appropriate climates from Fall to late Winter, or moist cold 30 days followed by light, indoors 60-65 F 10 weeks before last frost. Germination may still take 45 days.

But others will want consistent heat; some - moist warm followed by moist cold followed by cool...Can you give us a name?

The dormancies can be tricky. Putting a tray outdoors over winter is often the easiest way. Many species also prefer to germinate and grow at cool temperatures rather than a typical indoor 70F.

Primula auricula, japonica, and denticulata are the ones I had in mind to grow, I think. I've tried various, all of which required cold stratification. I tried leaving one of the cold trays (with a clear plastic cover) outside over the winter, nothing ever happened come spring. I tried one in the fridge for 30 days, then out, nothing ever happened. My seeds have always been Thompson and Morgan - I have read some people say they have not had good luck with their seeds, could that be it? Perhaps I should get them elsewhere. Thanks....

Primula auricula, japonica, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination

Primula denticulata, Surface sow at 20ºC (68ºF), germinates in less than two wks

Chilterns has a nice selection of primula; I have an annual seed order on it's way from them now.

Here is a link that might be useful: Chilterns

Thompson and Morgan are probably not the best for such perennial seed. They are handlers, getting the seed in from suppliers so have no real control over the age. Primula seed loses its viability very quickly with age so you need fresh seed.
Good seed of Primula japonica and Primula denticulata should not really be difficult. I sow on the surface of peat based compost(they need light to germinate) and keep the seed pans cool and shaded. I cover each pan with a sheet of newspaper so they are shaded and spray over the surface every so often with water. The seed must not dry out. The temperature must be kept below 60 degrees F. . if the temperature rises above that temp then the seed will go into dormancy which is then awkward to break.
I sow those species in spring and keep the pans outside or in a cold greenhouse with all vents open.
I have obtained seed from Plant World Seeds of Devon and from Barnhaven primrose in Brittany. Both firms produce their own seed and viability is excellent.

Just noticed the posting before mine. While Chilterns are very good at what they do they too are handlers. They just have an office and produce the catalogue. Sometimes their seed has been very good, sometimes less so. It depends on who provides that batch. If you can find a seed producer that will be the best.
This is a big issue with me . I resent the fact that some big seed firms (who are not averse to taking advantage of smaller competitors), using their money to produce glossy catalogues full of overpriced dead seed. They list some things as difficult, when they are easy to germinate if fresh seed is used. I have found this to be the case with Himalayan blue poppies which are so easy to germinate. Growing them afterwards can be a nightmare, but not germinating. The various forms of polyanthus and primula vulgaris are some of the easiest things to germinate. Novices then think they have failed and it is their fault, when the truth is they were sold rubbish in the first place.
So i8f anyone reading this knows of any firms in the US that produce their own perremial seed, particularly of unusual varieties, then I would be very interested, for my own use and for the benefit of the many contacts I have in the US. I would also be keen to extend my list of British and European seed producers as well.
P.S. The criticism does not bapply to Chilterens who i think are a very good firm. I use them because they offer so many different things, but I am aware that with some things viability will be out of their control.

With primula auricula and japonica tried to follow same instuctions that MorZ8 gave but sow at 60F, 90% seeds germineted in 1-2 weeks :)

The one and only time I tried primula japonica, the seed came from Chiltern's, and it did germinate just fine. I know I didn't do any major stratification, but I did start them in cool temps with light. If memory serves, I started them in moist coffee filters in baggies near a cold, east-facing window during winter--I figure the temps were somewhere in the 50s.

I would also have to agree with Geoff, as I grow many varieties of primula and I find that Barnhaven Primroses is an excellent source. Plant World Seeds of Devon and Chiltern are also very good but I have never purchased primula seeds from either of them.

On the other hand, since you are living in the United States your government requires that you obtain a phytosanitary certificate to import seed from outside of the country. The price of the certificate can vary from between $4.00 USD to $ 30.00 USD depending on which country you import from. That being the case, I would suggest that you purchase your seeds from Jelitto. You would not require a phytosanitary certificate to obtain their seed as they have a US office. The quality of their seed is excellent because they market mostly to growers. They also offer in excess of 2,000 varieties, many which are rare and unusual including pre-treated primula seed which will germinate without a cold period. Their brand name for pre-treated seed is 'Gold Nugget'. The only issue with Jelitto is that they have a minimum order of 25 Euros.

In my experience, Thompson and Morgan is not the best source for perennial and tropical plant seed although they are fine for annuals and biennials. If you purchased the seeds off the shelf from a retailer, I have the impression that it's not a question of freshness but of storage.

As far as seed suppliers who harvest their own seed in the United States, I can think of several but they are specialized in mostly alpines or North American native plants. That being said, these are collectors and not hybridizers like Plant World Seeds of Devon who are in my opinion very unique.

Rocky Mountain Rare Plants (alpines)
Alplains (native plants & alpines)
Western Native Seed (natives)
Prairie Moon Nursery (natives)

In Canada:

Gardens North (Hardy perennials for cold climates)
Beaver Creek Nursery (Alpines)

Marilena, I've received two seed orders from UK and one from New Zealand without buying the phytosanitary certificate this month (it wasn't offered for the quantity of seed I purchased). I do realize there is the possibility of having the seeds confiscated, but most companies will replace a seized order. In many years of overseas ordering, I've never lost a seed order to customs though I'm sure my turn is coming :)

My 'internationally known, well respected, UK seed company' order arrived this morning in a plain, address hand written, packet.

Morz8,

I know about that wonderful company because even though I live in Canada and we don't have restrictions, I get the same unmarked envelopes. I love those people - you wouldn't believe the money they save me on duties and customs fees! God Bless them!

But nevertheless, it's US law that you require a phytosanitary certificate to import seed no matter how little. It's my opinion that it shouldn't be applied to amateur gardeners purchasing a few packages of seeds and I especially find it absurd that Canada is included in the restricted countries considering that we share a border.

marilena
have those firms got a web sites? Plantworld do sell a lot of seed that has been wild collected. They have organised expeditions to various parts of the world. I would find it useful to be in contact with firms that are selling wild US seed.

Yes Geoff, they do have websites which I've listed.

I know that Ray Brown (Plant World) has done a fair bit of wild collecting. I remember his trips to the Sakhalin Islands and to Chile. My understanding is that he's worked extensively with Aquilegia and brought several new hybrids to market.

Rocky Mountain Rare Plants - www.rmrp.com
Prairie Moon Nursery - www.prairiemoon.com
Western Native Seed - www.westernnativeseed.com
Alplains - www.alplains.com - you will have to write Allan for his catalogue as his website isn't functional yet. Unusual plants, large quantity of seed, and wonderful service.
Gardens North - www.gardensnorth.com - fabulous species and service.

Beaver Creek Nurseries - www.rockgardenplants.com
Alpine plant seed and superb quality mail order alpine plants. If you order their plants you will be very pleased with the quality and service. They ship to the states but I'm not sure about Europe.