damping off

[SuazMember]

Hello Charles,

I was wondering whether you might be able to help me with the following query. I sowed sugar snap peas in 1.5-inch modules in clumps of three 10 days ago, and they appear to be growing well. However, on one of peas that was sown closer to the surface I can see white fibres radiating from the base of the stem where it disappears into the soil. Also on another pea that is visible through the cracked compost surface there’s a reddish brown lesion. Are these sings of damping-off, and if so, should I throw away both the seedlings and the compost and start again?

I have a similar concern about my lettuce seedlings (sown in 1-inch modules a week ago). Again, there were white fibres radiating from the roots right from the moment they germinated, and I wasn’t sure this was a part of the normal root structure or a fungus. The roots look feathery like the ones in the following photo: http://www.sciencephoto.com/media/34025/view. The same is the case with some of my Rudolph purple-sprouting broccoli.

Have I killed my seedlings? What should I do with the module trays – are they safe to re-use, do they need to be sterilised? Bear in mind that they’re quite flimsy.

[charlesModerator]

 Suaz I think you are worrying for no reason, in fact your plants sound (and look) healthy to me. White fungal-looking fibres is part of normal root growth.

Damping off is a dramtic falling over of seedlings where the stem starts to rot quite quickly and seedlings can turn to almost invisible mush within a couple of days. It is caused by excess humidity (really excess!) and actually happened to some of my spinach and beetroot recently, where I had fleece on them in recent cold weather, on my new hotbed in the greenhouse. I had not appreciated the amount of humidity rising from the heap! Luckily everything else is fine after removing the fleece.

Trays which have had damped off seedlings in them are not ‘infected’. As for potato blight, it is the prevailing conditions which count, not (supposedly) existing spores. Even if they survived the trays drying out, which is unlikely to say the least, they still need perfect conditions to infect plants.

[SuazMember]

Thanks Charles for giving renewed hope to my first-time veg growing efforts! It was very disheartening to think that my seedlings were all sick and moribund. I’m glad I won’t need to throw out my newly bought module trays either. Almost everything else I’ve read on the subject advised to discard potentially ‘contaminated’ equipment and bin the compost! As a precaution, I think I might be more careful with ventilation as my south-facing windowsill can get quickly hot when it’s sunny and perhaps also spray chamomile tea on the seedlings from time to time as it’s reputed to held prevent damping off. Oh and takes the lid off the propagator before it steams up too much!

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