Tuesday, May 19, 2026

Bringing Dahlias Out of Storage and Planting

 This is one of those projects that can drag out over days or weeks.  In the past, I have planted all of my Dahlia tubers in one fell swoop.  That's no fun.  That's a lot of work.  This time I have stretched it out over several stages and days and I'm not done yet.  And I have found it to be very enjoyable.  I also stored the Dahlia tubers in more than one place in more than one way.  For several years now I have stored them in deep tubs with coarse Vermiculite either in the workshop or the big garage with a thermometer sensor to ensure that the temperature stays between 45F and 50F.  I am still doing that, but I am also experimenting with some other methods and locations.  One of the other possible locations is our basement.  The basement is "unheated" except for the furnace being physically located there.  It stays about 65F to 68F all year 'round.  I have seen on the Facebook Dahlia group that other people have successfully stored in these temperatures as long as it is dark, humid enough, and constant.


Last year I wrapped a spare tuber in Saran Wrap and stuck it in a basement cupboard and it did just fine.  It did not dry out, and it sprouted about the same amount as Dahlias stored in other conditions.  This year I stored quite a few tubers in the basement.  I wrapped some in Saran Wrap and put the rest in shoebox containers with coarse Vermiculite.  I tucked them all in a corner against the rubblestone wall beside the pantry cupboard where they would be humid and be as far as possible from the furnace.  This is the same place that I store my potatoes.  And they all kept just fine.


The tubers closest to the surface sprouted a little.  The tubers wrapped in Saran Wrap also sprouted just a little and they stayed nice and firm.  The only thing with the Saran Wrap method is that you have to trim them down to single tubers.  You cannot properly wrap an irregular clump.


The tubers stored in a dark corner in the Garage at a constant 50F sprouted the same amount.


I have several different planting beds for the Dahlias.  My main bed is rectangular, and to ensure that every plant gets enough sun exposure I have to carefully plan their locations by height.  The tallest ones have to go in the Northwest corner.  I have highlighted my layout in grayscale with the tallest being the lightest gray and the shortest being the darkest gray. Sometimes, I know a varieties growing habit is not going to be as tall or vigorous as the internet reports, and I adjust their location.


It is really easy to get mixed up when planting a grid of tubers.  Years ago a friend asked me "when you plant your tulip bulbs, how to you remember where you planted the bulbs as you are planting?"  Well there are two schools of thought.  Either you lay out your bulbs first and then dig a hole under each one.  Or you dig all of your holes and don't fill them in until you have them all dug.  ...and he was an engineer!  I have struggled to figure out the best way to get a neat grid of Dahlias in the ground.  It doesn't work well to put support stakes in at a later date because you risk piercing the tuber with the stake.  So this year I carefully laid out string lines, measured, and placed the first stake for each tuber.  I then wrote out tags for each variety and placed them on the stake.  Then all I had to do was plant each tuber on the east side of its designated stake.


The single tubers are easy to plant.


Some of the larger clumps are not so easy.  Each Dahlia tuber should be covered with 4 to 6 inches of soil.  In the past, I have occasionally had Dahlia plants that would wilt every day when they were a foot or two tall.  Eventually, the hair roots would catch up and keep the plant looking fresh all day.  Each time I dug one of these up at the end of the season, I found that they were planted too shallow.  There was not enough soil to protect the tuber from the heat of the sun.  Once the whole bed grew in and provided some shade for the soil, they would be OK.  But you risk losing the tub to too much water as you try to keep it from wilting.  If this starts to happen to one of your Dahlia plants it would be better to throw a mound of soil on top of it and up the stem to attempt to bury it to a safe depth.  **see note below regarding "hilling" like potatoes....


As I plant, I add a second and maybe even a third stake depending on the variety.  They may not be as straight as I'd like, but a safe location is marked and I can drill a straighter hole later.


After the tubers are all planted, I can plant the border plants - my Marigolds and Zinnias.  At first I keep them covered to slow down casual nibblers and curious diggers.


I am very pleased with the orange Profusion Zinnias.  Most of the flowers have dark highlights.  Some people may complain that they are not a pure, even color, but I really like it.


They will look great along side my carefully curated palette of copper, bronze and peach Dahlias.

I got most of the pink and purple bed planted on a hot sunny day.  I decided to wait on the full sized plants that I "woke up" in a tray of soil.  They hung out in the protection of the cold frame until the 90F and windy days passed and then came out of hiding this afternoon.  The one I did plant early I protected with a trash can.  In fact, when I finished planting the Marigolds and Zinnias on this side such a stiff, hot wind kicked up that I put trash cans over them too because they immediately looked wind blown.


I finished planting this bed this afternoon, bringing the sprouted tubers out and planting them as I would any other potted plant.  You can bury the stem quite deeply to support it, and, apparently, according to the Dahlia Growers Facebook page, the plant will send out additional tubers along the stem at the buried leaf nodes. Some people actually hill them like potatoes.  None of mine really need to be supported by a mound, but if it comes to that I will not hesitate to try it.


Now all that remains to plant are my Dahlias started from seed, both this year's plants, and last year's stored tubers.  I may even place some of these randomly in the landscaping for annual color.  This time of year my To-Do List every day is all plant...plant...plant.  Other chores, like weed....weed...weed, keep getting pushed to the bottom.   We are now expecting a week of cooler, wetter weather which will be better for transplanting my tomatoes and pepper plants than 90F (32C) and windy.  Today I seeded sweet corn and began warming the bed for pole beans.

a beautiful Aquilegia Songbird Blue Jay is flowering

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