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Need help with my dahlia tubers I'm starting indoors

Posted by graceSF 8 (My Page) on
Wed, Mar 13, 13 at 15:58

I just got around to getting my tubers out to start inside. They've been sitting in their packages in the garage. I opened them up and some have quite large sprouts already. Most of the sprouts are white in color and some are even dying at the tips because they haven't been getting any light. A few have reddish stems (i believe they are the darker foliage types) and are really long. I'm wondering should I trim these sprouts down and let them regrow? If I leave thm will they turn green and healthy? Some shoots are quit long maybe five or more inches. Some shorter just 1-3 inches and very pale white. Not sure what to do. Can someone please advise?

Follow-Up Postings:

RE: Need help with my dahlia tubers I'm starting indoors

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.

RE: Need help with my dahlia tubers I'm starting indoors

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 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!

RE: Need help with my dahlia tubers I'm starting indoors

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?

RE: Need help with my dahlia tubers I'm starting indoors

Hi Grace

My answer may not help you at all but...

I live in Sf and have grown dahlias out in the sunset for years (which is one of the worst environments for growing flowers) and in my opinion, you are causing more work than you need to for yourself.

I NEVER have started my dahlias indoors, I never have dug them up for overwintering and I rarely even touch them after they bloom in year one. And I (just being honest) have a yard that is the envy of my friends and neighbors.

Even in heavier rain years, I never worry about my tubers and in years like this, I find I have to go out and water in the winter in order for them to get ANY moisture.

Do I lose dahlias? Sure do. But not often and usually only when I am lazy and allow the snails to have at em when they start sprouting. But if I lose a few (out of 90+ and counting), it gives me an excuse to buy more tubers the next year!

You may well grow beautiful dahlias with all the dedication you are showing but for my money, it is much ado about nothing. Dahlias are hardy and once they get used to their environments, they last forever. And you know well in the sunset we get up to 2-3 months of NO SUN and heavy fog. So if I can grow beauties with little maintenance, I am sure you can also.

If you prefer the high maintenance route, go for it. But I think you will find it a full time job because there will ALWAYS be something - mold, rot, lack of water, too much water, snails, too much heat (sun), not enough heat, freezing temps, long foggy months, staking, and maybe , just maybe, the tuber was no good from the get go DESPITE what you do!

Good luck. And if you live in the sunset and want to see my yard some time, I have dahlias from May to November but the best month is August. Come on by!

RE: Need help with my dahlia tubers I'm starting indoors

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:-)

RE: Need help with my dahlia tubers I'm starting indoors

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.

RE: Need help with my dahlia tubers I'm starting indoors

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.

RE: Need help with my dahlia tubers I'm starting indoors

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.

RE: Need help with my dahlia tubers I'm starting indoors


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.

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