Yes you can cut back the sprouts.

Are you going to put them in pots for a while? or in zone 8, can you plant them out soon?

Here (WI), I start them in pots either under lights or on a window sill so I can get a bit of a head-start. If they are still at the sprout stage when I plant them outside, I cut the sprouts back to an inch when planting. However some of them are actually 12-18" plants by the time I get them out.

With the longer sprouts you could actually cut them and try rooting them. Its a common way to propagate Dahlias.

I won't be trying to wake mine up for another month. I cant plant Dahlias here until the end of May.

Thanks for answering my post! I could possibly plant outside but we do get a bit of springtime rain. I'm new to growing dahlias so I'm following guidelines from the San Francisco chapter of the dahlia society. They recommend starting them indoors and moving them in April. The sprouts don't have any green leaves yet so I was thinking if I cut for trying to propagate they may not survive...is that correct? All the pictures of the sprouts on the dahlia society page are so green and vibrant. Mine are sad and sickly looking. I'll take your advice and trim them down a bit. Maybe that will help them become healthier? Thanks!

So I've got all my tubers set up in little beds under lights. Lots of little sprouts are showing. I've got a few questions. I'm using some trays that have humidity domes and these covered ones seem to keep their moisture better than the uncovered ones. When the sprouts really get growing do I take the domes off? The uncovered ones seem to be really dry and need spritzing a lot. And my next question is how do most keep their mediums moist? Spray can? For me, this seems to only moisten the top bit. The tubers seem pretty dry. I'm worried they will get too dried out. I did notice on a couple tips of my tubers that are sticking out, there has been a tiny bit of fuzzy mold. What is the best way to deal with that?

Thanks David in SF. Yes, it is a challenge gardening in the sunset. I did not dig up my tubers from last year and most of them rotted. I maybe have 1 tuber that might give me something. My son was pretty upset that everything was lost so I'm going to put more work into it now. Everything I'm starting now are new purchases. I am starting indoors early because I want blooms earlier than I had last summer. I know it's a lot of work, but I need a hobby:-)

Hello Grace

That is very odd. I don't know WHERE you live but of my 77 dahlias last year, only one rotted. And it was actually no good from the get go because the dahlias planted near it are fine and producing dozens of 'offspring' tubers. It was a first year dahlia also.

Living in the Sunset, my soil is obviously mostly sand, which drains well. Last year, though we had more rain in Spring, it was just as dry from Nov to March as this year, so I can't believe you lost all but one.

In any case, good luck. If you ever are on Noriega this summer, drive by 27th Ave and look at the center divide where the City installed some cement planters. Some of my extras wandered over there and somehow planted themselves and they should be blooming by summer.

I know! You would think they would have survived. This is my theory, they were all planted in containers, I think the soils couldn't fully dry out even when I spared them from the rain. Secondly, I used soil mainly purchased from sloat. I have found that their soil is way too heavy and water retaining for the sunset. I had a huge problem with root fungus last summer. I have switched soils and have been amending with sand and things seems to be better. It was my first summer having dahlias and luckily I only had about twelve. This year I have multiplied to about 36, so we'll see how it turns out. The digging up and storing makes me feels like I'm in college biology again. The 3 tubers I tried to save from last year still have no sprouts but I am hoping something pops up soon. I also have a terrible slug problem that even sluggo doesn't seem to take care of. Another reason I'm scared of letting them sprout outside. Do slugs sprout wings in the middle of the night??
I will look for your Dahlias on 27th.

Oh and one of my dahlias became a nest for ants. Have you ever seen or heard of that before? They were living in the center of a clump. A very large clump that definitely needed dividing.

Grace

Of my 90 some dahlias, at least 20-25 are in containers. I had a Rip City rot in a container a couple years ago and found the holes draining the water were plugged. It is something you have to watch for. Most of the time it can 'seem' dry on top or a few inches down but go 7-8 inches down and it is ALL WATER.

As for snails, don't get me started. When I first cleared my weed invested yard, I found everything living back there - rats, ants, even a small white mouse - but especially snails. Sluggo will NOT work (IMHO) and even though many people disdain using Deadline, it is the only product I found that would kill the snails. And I had hundreds. Now, I find or see 5-6 per year in the whole yard.

What I also noticed was when you put a ring of deadline within the container edges, those particular dahlias do not do as well as others or in ground dahlias. Despite what deadline says about it being safe for plants, that has not been my experience. But it's a catch-22: if I DON'T use it, the snails will eat the shoots right away and if I do use it, I might get blooms that look half strength.

(I think the only answer is to stand guard every night once the sprouts break ground and grab'em before they make it to the plant!)

Ants I have never had a problem with but if you PLANT a tuber within an ant colony, it makes sense they would be all over the tuber. If you planted the tuber where NO ANTS were, I'm not sure what to say - I've never heard of ants being a problem for dahlias or attracted to them. Earwigs, yes. Ants, no.