Stem damage to seedlings - what's the cause?

General tips / questions on seeding & planting

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Pawty
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Hi,

Hoping someone can help me! A few days ago I noticed all my kale seedlings (young) had pretty much died. I had transplanted them and figured they didn't like it. I noticed on the stem at the soil interface there was damage to the stem but didn't think too much about it. When watering my fennel (photo below) and lettuce seedlings today - neither of which have been transplanted - the same thing has happened. Will have to bin the lot.

All were potted in a fine seed compost, which I noticed did dry out quickly. Wrong soil? Not enough water? Too much water? The germination of lettuce in this (we'll know branded) seed compost was slow and rubbish.

Any help much appreciated so that I can start new seeds off and do the right thing!

Thanks

Pawty
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Westi
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Blimey Pawty!

Can't help with what it is as not experienced it before - but it is weird. How many more challenges to face, poor germination & mutant seedlings. The only thing I can think of did the seed case get stuck for a bit?
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I've been blaming the seeds, could be the compost as the growing conditions I have this year is way better than last year, but have worse results. Not everything has failed, but the percentage is disappointing.
Been gardening for over 65 years and still learning.
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peter
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It looks like "Damping Off", see www.edinburghgardenschool.com and here's a picture I nicked off the page.
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Pawty
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Thanks Peter - yep, that looks like it!

I've heard of damping off but never looked into. Just googled causes and there are so many (looking at the rhs website). Suggests using commercially bought compost .... dare I say thar this may have been the common factor?? Maybe combined with the weather conditions.

I'll replant in different compost - may also explain rubbish germination as it says it can attack before any growth.

Thanks again.

Pawty
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Primrose
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I think the trouble with some composts is that they simply get too wet and it causes rotting or dampening off in too many cases. Especially when sowing very tiny seeds. . It has happened really badly with my climbing beans , and once the compost is that wet the damage gets done to tiny seedlings all too quickly.

For my sowings going forward, especially as we,ve had such dry weather I'm adding a small proportion of ordinary fine soil from my garden borders to my growing compost and mixing it in well. This seems to make a thicker, more controllable growing medium which retains the moisture but doesn seem to remain sodden and boggy in the same way that 100% compost from a commercial bag does. I don,t know whether this will resolve dampening off problems but my latest batch of resown climbing beans in this mixture looks as if they might be starting to germinate instead of rotting as most of them did previously
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Always water seedlings with tap water to reduce the risk of damping off. Water from water butts is far more likely to carry the fungal spores.

I have started covering seeds with vermiculite instead of compost and this works very well. I can't remember the last time any collapsed.

I did have the bean problem but will soak the seeds for a couple of minutes in a very dilute bleach solution as Sally Wright suggests.
I wonder if anyone has tried watering their newly sown seeds with dilute bleach solution? I don't think I'd be brave enough to risk killing my seeds.
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Geoff
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I thought damping off, good picture Peter's found to prove it. Used to be easy to avoid with Cheshunt compound but that has gone the way of most copper fungicides, I wonder if the new stuff they are using on grapes will prove useful.
Don't know what causes you found by Googling but the easiest way to avoid is well spaced out seedlings. With vegetables you only usually want relatively few plants so use a module tray that suits the quantity you want to raise and sow two or three seeds per module and thin to one as soon as they emerge (or single seeds for expensive F1's).
This year, as I have said before, I've used the peat based Clover Professional Seed Compost and had excellent results. I part fill the modules either with multi-purpose or home made and top them off with the seed compost. Again my routine is fill the trays, water them, let them drain and acclimatise to where they are going to be sown, sow and either dibber bigger seeds in a little or cover with fine vermiculite or a 50:50 compost vermiculite mixture. Try not to water them before germination, mist them if the surface starts to dry. Really big seeds like peas and beans push into the damp compost and cover with more compost straight from the bag and again only mist before they emerge.
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I have heard cinnamon powder sprinkled on the top of the compost stops damping off. I tried it for the first few trays but then forgot, so can't comment on success as they all got mixed up.
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