seed sowing - when to give up

REMF33

I am not sure what category to put this in... I am newish to growing flowering plants from seed. This is year 3. (Year 1 being quite a dilettantish modest attempt; last year more concerted; this year, a very concerted quite ambitious attempt, complete with grow lights as well as windowsills!) I am far more experienced in growing vegetables and vegetable seeds seem to come up very well and reliably. (I suppose, as my mother says, there is more of an urgency for annuals to come up quickly.) But my success with flowering plants is much more patchy. (I have some viola odorata sown a month ago - still no sign. Ditto aquilegia and Hungarian blue poppies. I am not surprised about the meconopsis. All the seed is this year's.)
Obviously one needs to read what it says on the packet. But do people persist with seeds that have not come up after the suggested period on the packet etc.? And if seeds from the same packet have germinated in one pot but not another is this a sign that the ones that have not come up are 'duds', and I should resow?
I realize it's not a precise thing, but just wondered what other people do. For most things, at the moment there is still plenty of time to resow.

AnniD

Personally, if it hasn't appeared after the supposed time, l tend to start again. I might give it another week, but that's all.
If they are perennial seeds l may leave it another couple of weeks, but l find that annuals (both hardy and half hardy) generally appear within the designated timescale. 
Perennials such as aquilegia are very patchy, l had some l was convinced had failed and then just l was about to get rid of them,up they popped.
It's always strange when one lot of seeds are fine and another set are duds even when treated exactly the same. I resow in that case.
All part of the joys of gardening. Love it.  

Dovefromabove

I sow aquilegia in the early autumn (September IIRC) and leave them in a sheltered corner of the garden or in the cold frame over winter ... they usually pop up in the spring.  I prick out and then pot on for the rest of that year and only plant out the following spring.  I have aquilegias, sown in autumn 2019, to plant out this spring 

Butterfly66

I usually give everything a good few weeks grace but I do all my sowing in an unheated greenhouse so that does make some things slower. I think if I was giving them optimum conditions I would probably re do them if nothing was showing a week or so after the expected time.

Zenjeff

Meconopsis some times take a good time to germinate seed must be fresh and plant in autumn leave outside to get chilled should show in spring if you are lucky.one of my seedlings ,water from the bottom as they have a habit of damping off.

fidgetbones

I tend to dump seedtrays  with ungerminated seed in a particular corner. It is surprising what can come up later. Peony seeds came up after three years.

REMF33

I am pretty sure I will not be able to grow meconopsis anyway where I live. I have bought some plants as well (purchased before I fully realized this) and even in the cold weather they are not exactly thriving. Will donate them to my mother 'up north' when I can get up there.
I have put a small tray of ungerminated seeds in a cold frame. I can spare the pots, so I thought I might as well. 
I am struggling to get nigella going... either directly (perhaps the weather) or inside.

Lyn

Very tricky growing Himalayan Poppy, I wanted to have a go but they wouldn’t be suited to my climate or soil.
Why not try easy seeds to give yourself some encouragement, try cosmos, marigold, dahlia, they’re all easy and germinate well. 

Mary370

Some seeds are just slower than others......half hardy annuals and annuals usually germinate very quickly at this time of the year.  Perennials often need a period of cold, therefore are better of sown in the Autumn, such as your viola and menoconspis.......don't give up!!

Ceres

Some seeds just never seem to want to grow. I have had no luck at all with viola odorata over the years but I do have a lot of them growing in the garden, brought by the birds. I think it is sometimes a good idea to buy a plant if it proves to be awkward to grow from seed. With a bit of luck it will self seed and spread around the garden. Not only is this easier than toiling over reluctant seeds but you also get some interesting variations.

debs64

I agree, could never grow verbena boriensis from seed, invested in a tray of plants and now I have them coming up everywhere! Luckily I love them as they are in cracks of paving etc, I just pull them out gently and pop them where I want them.