Damping off sprouting Tuber

Adriana

Hello everyone!
I’m a little in shock right now. I have had many tubers eyeing up/sprouting in pots, baggies and trays for a couple of months now. I am planning to plant them this week. This morning I noticed my sweet Nathalie sprout ( 1”) which is in a little plastic pot had fallen over. Upon further investigation I noticed the sprout was black and shriveled at the soil level. The soil was dry. Tonight, as I brought some pots in from outside I noticed two more sprouts in two different pots had fallen over at the soil level. They are Roque Starburst and Breakout. Those sprouts were about 2-4” inches tall. The soil was not wet nor even damp and I have been hardening them off outside.
I have never had this happen before with dahlias. I have been growing dahlias for about 5 years now. I had damping off with my tomato seedlings years ago but never with my dahlias.
I took off the sprouts from the tuber and sprayed the surface of the soil with hydrogen peroxide. Is there anything else I should do? Any advice would be appreciated.
Thank you! Have a good night!

Bessie

Adriana, I suggest removing the soil from one of the tubers and examining for tuber damage. You may find a pest or insect infestation. The tubers may be rotting, or the soil has gone dry. I've had a nightmare keeping fungus gnat larva away from my tubers. Perhaps the soil came with some pathogen? Post a few pictures! Let us see the wilted sprout and what the tuber and accompanying soil looks like unearthed.

Adriana

Thank you so much for your reply Bessie! The tubers seem fine and where the sprouts attached to tuber was still green and not rotted. I already detached and tossed the damped off sprouts last night. If there are any others that have it this morning I will take pictures. Could be something in the soil. Using mostly organic coast of Maine soil in pots. Months of growth down the drain.😕
I have a short growing season too.

SteveM

Adriana A couple of possibilities if the sprouts are only blackened above soil line:

Soil temp too hot at the surface and tender sprouts are burned (fried).
Snails (or some other critters) have chewed the sprouts at soil level.

Adriana

SteveM
Thanks for your reply Steve! I do think it may have been the heat. The tubers are still firm and intact. The pots were outside in the sun probably a little too long. The leaves were not sunburned at all but it just may have been too hot out and the soil too dry. Thankfully, I’ve had no other casualties since then.

blown_dry

If you have garden soil in the pots, instead of some sort of potting mix, that may be part of the problem. Sorry you are having trouble.

Adriana

blown_dry

Thank you blown_dry, I appreciate your reply. There is no garden soil in the pots just potting soil. Thank you, it’s disappointing to lose a sprout when you have a short growing season and you’ve been babying them for months and your house looks like a plant nursery but it could be worse. Lol

Krista

Adriana This happened to one of mine last year when we had an early spring heatwave in Seattle. I removed the sprout (also not sunburned, but very wilted) from the surface of the soil and can confirm the tuber generated a new sprout and the plant grew just fine!

Adriana

Krista
Thank you so much Krista! 😀
It seems like the consensus is the heat. I did have the pots in the sun and the maybe tender sprouts just couldn’t handle it especially since the soil was on the dryer side. I am planting in the ground this weekend, so hopefully they will all grow new sprouts and I’ll have beautiful blooms come July/August. You live and learn! Have a good day and thanks again.

MIDahlias

Is dampening off the same as the sprout burning and breaking at the soil level? If not, what is dampening off?

Adriana

MIDahlias

Hello MIDahlias! That’s a great question! It looked exactly like damping off to me. Damping off is caused by a fungus that thrives in cool wet soil and usually affects seedlings and young tender plants. I was confused because my sprouts were in dry potting soil and they were outside on a sunny day. I was hardening them off and probably left them out in the sun too long . That’s when I decided to post here and ask more experienced growers for advice. I have since learned that my sprouts most likely got too hot at the soil level and the stems were damaged. I am no expert but I hope this helps. Have good day!