Damping Off - a warning

[teakdesk]

This is more of a warning to newbies (OK...... an admission of my own failings) that watering weak seedlings from above really does cause damping off (ie kills the seedlings dead without any hope of rescue!! ).

I've always watered my seedlings from above and in the past 35 years I've never had a noticable problem with damping off. In fact I didn't really believe it happened!!!!

This year I have had a table in our dark-ish hallway next to the radiator as an extra area for germination. Due to lack of space many have stayed there long enough to become a little leggy (some not even noticably leggy, just "well germinated").

After joining my other seedlings that were germinated in better light I watered them all exactly the same (ie from above) but the "hallway" seedlings succumbed to damping off and died; the others continued to grow strongly.


I hereby apologise to all those sages I have poo-pooed about top watering and damping off... if seedlings are strong then maybe top watering is ok but if not then water from below.... and do not over-water!!!!




Humble pie mode now switched off.... arrogant mode resumed

[BumbleB]

Thanks for this teakdesk
I have potted on 45 tomato seedlings today into 3 inch pots from their original yogurt size pot. I have then had to hunt for trays or saucers in order that I could water from the bottom. I have just checked them all this evening and they seem happy and settled after their move :-)

Moral: They are babies, and need treating with kid gloves !

[Two_Sheds]

Also, don't water seedlings with old water butt water, that might contain fungals *
Tap water or fresh rain water is best.


* is that a new word I made up?

[stupot]

* yes I think so.

[smallblueplanet]

...This year I have had a table in our dark-ish hallway next to the radiator as an extra area for germination. Due to lack of space many have stayed there long enough to become a little leggy (some not even noticably leggy, just "well germinated").

After joining my other seedlings that were germinated in better light I watered them all exactly the same (ie from above) but the "hallway" seedlings succumbed to damping off and died; the others continued to grow strongly.

Perhaps the 'damping off' was due to the 'fungals' that grew whilst the seedlings were in the dark hallway, rather than down to the top watering? Else all seedlings would have succumbed? Surely you should stop using the hallway for seedlings, not stop top watering?

[snohare]

* is that a new word I made up?

No, 'fraid not Two Sheds. The NTS around here regularly conduct "fungal forays". But if it's any consolation, I think it might be a scientific word so I'm still impressed !
Speaking of fungi, it is pretty simple. The spores are swept up high into the atmosphere by upwellings of air from the ground, and come back down to earth in rainclouds; in fact, they may act as nuclei for rainclouds to form. If there is sufficient UV and warmth, they will not reproduce successfully; a spore is basically an Ultraviolet, temperature and chemical-proof coating for a seed, in some species more effective than in others. If there is not enough UV, heat or whatever will kill them, and if the right humidity and temperature is there - basically, if it is warm and damp - then after a certain time, which again varies by species, the spores give birth to the active mould, which attacks cells on the plants, sucks out nutrients, grows, reproduces...we all know the rest. Spores in the soil often get onto leaf surfaces, which are extremely vulnerable because of pores etc, via raindrops that land on soil and splash back up onto the plant.
Plants of course do have defenses against fungal diseases, they absolutely need to have Willows are prone to hundreds of fungal pathogens, and roses are not far behind; an infectious burden that eventually kills. But if the plant is struggling to absorb nutrients it can't fight off the infective spores so well (possibly due to lack of trace elements) and so will succumb when a healthier plant in the same circumstances won't. Hence, some happy plants and some dead plants...

Autolecture mode off, bumbling gardener mode back on...

[ckfe]

watering from the bottom?

how do you water seedlings from the bottom if they're in a peat pot?

[FionaH]

how do you water seedlings from the bottom if they're in a peat pot?

Carefully? I dont to be honest I start seedlings off in modules then transfer to peat pots when they are bigger, and water from the top. Probably the wrong thing to do though!

[SarzWix]

Peat pots soak up water, so you can still water them from underneath...

[FionaH]

See I knew a clever clogs would be along soon! But but but dont the peat pots go all soggy and yukky if you do that Sarz?

[Florence Fennel]

See I knew a clever clogs would be along soon! But but but dont the peat pots go all soggy and yukky if you do that Sarz?

Hi Fi, I have just been on another thread where people are sick of seed trays and 3" pots and I had a moan about learning the lesson of watering from the bottom instead of being able to do it quite quickly with a watering can. I bought two large gravel trays from Wilkinson that I keep outside. They fill with rain water (or tap) and I stand the trays in that. The peat pots I put closely together in brown plastic mushroom cartons and water into them. The peat pots have been remarkably resilient. They take up the water and you can really see when they need more. They didn't break up and I was able to pot on very easily.

[FionaH]

Great, thanks for that Florence