When germination fails.....

[Primrose]

I imagine most of us have suffered this problem at some time or other. Half my courgettes and half my cucumbers have failed to germinate this spring and I always have the dilemma of wondering how long I leave it, once the first few seeds have shown their shoots, before deciding that the others have failed and start sowing again.
I often tend, at this point, to do a little excavating in the soil and if I can't find anything, or a rotted seed, sow again, one the basis that all seeds of the same variety should have fairly similar germination periods.
How does everybody else approach this problem?

[oldherbaceous]

Dear Primrose, if they are seeds that just need normal growing conditions to germinate, i just give them a set time to do their job, depending on what type of seed they are. Then it's just use, what has germinate, or chuck the lot if no germination is showing.

Of course this does not apply for a certain type of seeds that need stratification and the like.

[WestHamRon]

Dear Primrose, if they are seeds that just need normal growing conditions to germinate, i just give them a set time to do their job, depending on what type of seed they are. Then it's just use, what has germinate, or chuck the lot if no germination is showing.

Of course this does not apply for a certain type of seeds that need stratification and the like.

I've never seen this word used on a gardening forum before,OH. What, in a gardening context, does it mean?
Thanks in advance.

[oldherbaceous]

Evening WestHamRon, it sounds more technical than it really is.
It just means to put seeds through a freezing, thawing process before germination will take place.

A lot of tree seeds and certain plants need this to germinate.

[Geoff]

We grow seeds each year that we get from the RHS Harvested Seed Distribution Scheme. These are all sorts of trees, bulbs and herbaceous plants. Each year they send out an interesting little booklet of hints and instructions to help you get the best out of the seeds. They tell you how to get pots ready how to sow and some comments on covering. They say don't cover fine seed, if seed is expected to germinate within 30 days cover with 2 to 10 mm of vermiculite depending on size, for long germination times cover with 6 mm of coarse grit. They tell you how long germination is expected to take. Some need cold moist stratification - up to 12 weeks in a fridge, they might need cold or warm soaking, or warm stratification - several weeks in an airing cupboard.
Some are complicated like Lilium - pre-soak in cold water, warm stratify for 4 weeks, cold stratify for 12 weeks, may take more than a year to germinate.
Strange one this year was Meconopsis Napaulensis which required cold moist stratification so they went in the fridge 21st February, when I took them out today they were already germinating disproving what you would expect.
Some of last year's sowings (Rudbeckia and Gladiolus) are just germinating showing you have to be patient.

[alan refail]

Hi Primrose

To get back to courgettes and cucumbers. These often rot internally if the compost is too cold. Did you sow them on heat?
You have plenty of time to start again. I never sow courgettes, squashes or cucumbers till about 24 April and find that plenty early enough for planting out in polytunnel or outdoors.

[Geoff]

If I am sowing in the propagator I fill the pots / trays the day before, water them with Cheshunt compound and put them in the propagator to warm up. I also have a water spray in there so they are watered with water at the same temperature.

[Catherine]

Or you could have done something like I did last month. I filled 24 pots with compost and wrote the lable for sun flowers, I must have got distracted because I looked after these pots for at least two weeks without seeing anything. SO I dug down in one pot and could not find a seed, then dug down several more pots, no seeds silly me will now have to start again. (numpty)

[glallotments]

Large seed like cucurbits tend to do better if sown on their side rather than flat but regarding amount of time. If the seeds don't germinate in the time expected we sow more even if we end up with two lots.

Courgettes eyc don't take long to germinate and if others have started then I'd sow again.

[Monika]

I am wondering, like somebody else on another thread, whether there is some contaminated seed compost about this year. I have had almost nil germination from some of my brassicas which I sowed about three weeks ago. Normally, they come up like mustard and cress. They are in the greenhouse, only heated to remain frost free this time of the year, and are shaded from the direct sunlight during the day. Still, hardly anything has come up.

Having bought and used different potting composts from different sources recently, I can't really pinpoint what make it was, but I wonder if anybody else had problems, too, like Primrose and Chantal's tomatoes.

[Primrose]

I confess to being really foxed on the seed compost issue because there seems to be no industry standard or kite marked product to rely on. Unless you're relying on your own home grown compost, which for many of us is probably too rough and thickly fibred for seed sowing, there seems to be nothing in garden centres which differentiates one product from another in terms of quality. On several occasions I've actually used surplus product from growbags for seed sowing, rather than specific "seed compost" and sometimes had better results. Some seed compost I find becomes really sodden when watered, doesn't dry out sufficiently and probably causes a lot of seeds to rot.
I have absolutely no idea what the difference is between these two products and the desirability of using one over the other.
Perhaps we need Johnboy's many years of experience here to enlighten us please?

[John]

Hello Primrose
I agree with you. There is a bewildering array of composts in the garden centres of variable quality and quite a lot of it is not much good.
I keep trying different ones till I find a good one then stick with this until the quality changes. That's another problem - a particular compost can vary a lot from time to time and from year to year. At the moment I'm on B&Q multipurpose. It has good texture, seems to be all peat and holds water well.
Sowing compost needs to have low nutrient levels, neutral pH and a fine texture.
For seed sowing I sieve this multipurpose compost and sow into small quarter trays, small pots or small modules. When the seedlings emerge I pot on using compost straight from the bag. This way I use very little compost for actual sowing. I start everything this way except carrots and parsnips which I sow directly.
It will be interesting to hear what JB has to say on composts as I know he used to produce small plants commercially.
John

[Chantal]

Hi Primrose

I pregerminated all my courgette seeds last year and they started sprouting within 3 days. I potted them up and they all grew beautifully. It certainly took the guess work out of it.

As for the comment about the compost and my tomatoes, my brassicas were in the same stuff and are growing well, so I don't think this can be an issue.

[Primrose]

Chantal - I think pregerminating might be a good idea to avoid the time delays of possibly having to resow. Do you do it in the same way as parsnips, i.e. putting them on damp tissue paper?
Do they just need normal house temperatures, or higher temperatures such as an airing cupboard?