Brassica seedlings - really want to keep them alive this time

[electric landlady]

Hello
A new year and a new batch of PSB and calabrese seedlings. This year I am determined to get them to actually grow into little plants instead of shrivelling up and dying when they reach the two leaf stage.

I would be really grateful for any advice about how to treat them. So far I have sowed two seeds per module into a 12-module tray of peatfree seed compost, stood the tray by a sunny window in a fairly cool room (about 17 C) and covered it with a sheet of bubble wrap. I am keeping it moderately moist by watering from below. It's only been two days so obviously they haven't popped up yet but when they do I am planning to remove the bubble wrap, continue to keep moist and move out of the direct sunlight.

Is this right? Is there anything else I can do to avoid the dreaded 2-leaf shrivelled seedling death syndrome? Any advice very gratefully received 

[Tee Gee]

Is there anything else I can do to avoid the dreaded 2-leaf shrivelled seedling death syndrome?

Its sounds like you suffer from either one or both of the following.

1) Damping off! as a general rule this is caused by over watering.

2) Sun scorch they might be to near the glass and even winter sunshine will scorch them ( the glass magnifies the suns rays.)

So once germinated do not water (unless it is essential)and avoid direct sunshine and leave the bubble wrap off as this causes condensation which also encourages damping off!

As soon as you see signs of the proper leaves get them pricked out into deeper containers i.e. sunk up to their seed leaves.

http://www.thegardenersalmanac.co.uk/Data/Pricking%20out/Pricking%20out/pricking%20out.html

[Ian Pearson]

I comply with Tee Gee, coming down on the side of damping off.
Were you using multipurpose compost? Compost companies will deny it, but I'm convinced over-rich (ie "multipurpose") composts contributes to the problem. I believe the highly available nutrients are bread and butter for fungal spores landing on it - especially if it is well watered. The fact that it is sterilised when it went in to the bag does not mean that it is sterile when the seeds emerge through it.

I almost never get damping of of seedlings. I use spent compost with a bit of sand added to speed drainage.

Other advice would be:  sow thinly to avoid overcrowding, water only when required, ventilate, provide high levels of light (sunlight is a mild fungicide), and pot on as soon as possible.

[electric landlady]

Thankyou!
I'm using seed sowing compost so it shouldn't be too rich for them.

I will definitely keep them out of the direct sunlight and not too damp.

None of my other seedlings ever get damped off, it's always just the brassicas, but it happens every time and so now I'm paranoid about it. Also, I associate damping off with the stalk of the seedling rotting first, whereas with my brassicas the edges of the leaves go first and then it gradually spreads down to the stalk.

[Tee Gee]

I associate damping off with the stalk of the seedling rotting first, whereas with my brassicas the edges of the leaves go first and then it gradually spreads down to the stalk.

Your association with damping off is correct and now that you mention the leaves are shrivelling up .............then I would say 'sun scorch!!

I did think of this initially as I mentioned previously but was unsure so I mentioned both!

When they are affected with 'damping off' they flop over but they don't shrivel as such.