Potting up Dahlia Tubers - Starting Indoors - April 2026

Just a few days, I posted a 'musings' post on starting my dahlia tubers and talked about the  when/how/what/where of starting the flower farming season here in the garden. 

Last year, I potted up the stored tubers right at the beginning of May and this year, I talked about trying to get it done a little bit earlier.  Today marks a few days shy of two weeks earlier.  That's pretty good, right?  

The 10-day forecast shows ZERO days below freezing, but I'm not holding out hope that the last freezing temperature is behind us.  The State Climatologist Office for Illinois has a last/first frost table up on their site that I tend to use more than the Old Farmer's Almanac version.  

On the Illinois version, they have a map up showing the "earliest" last Frost date (for us, it was April 9th).  And the latest (May 28th).  The map showing the median lists April 28th for DuPage County.  And, that's just ten days away.  

So, time to get busy dahlia'ing.  

Last November, I dug up all the tubers we had around the garden and used the "Saran Wrap Method" to preserve them.  Some of the clumps were BIG.  Some were smaller.  I did NOT divide them last Fall.  So, I began that process this week.  Below are some photos.  First is one of the 'smaller' clumps in plastic wrap.  I stuck a coffee filter in the bottom of the one-gallon nursery pots to try to keep the potting mix from running out of the bottom.  That seemed to work well last year. 

I started with the 'stored' tubers, then moved on to the new ones from Longfield Gardens.  After a while, I began to have a small colony of nursery pots that I had filled-up to varying degrees.  I wrote out a little plant marker and stuck it in each one so I know which ones are viable and which aren't.  

A few hours later (and another trip to the hardware store for some additional one-gallon nursery pots), I hauled all of them out of the garage and put them on the driveway to water.  Here's where we landed after the initial planting push:  91 tubers potted up.  NINETY-ONE.  Eeek.

Last year, it was just two weeks before most of the tubers had sprouts that emerged, so if that pattern holds, that means that right around May 1st, I should have some green tips.  

That's also when I will know the viability of these tubers.  I certainly don't expect a perfect hit-rate in terms of viability.  After all, I had never divided tubers before.  I'm thinking that between some of the tubers being 'blind' (not having eyes), rot and difficulty from being divided too harshly, I'll get something closer to 50% success-rate.  

Even so, that's more than I can use in our garden.  My family and friends will be the benefactors of any overage(s).