Lift them every 3 or 4 years in order to clean them up and thin them out for the best blooms.
Also, keep in mind that if you do not lift them and you have a colder year, wetter year, snowier year, you might indeed lose those tubers, bulbs, corms ... that you have grown for years.
This post details dahlia's and glads, but the same technique applies to all the various tender bulbs that you would lift in fall... Canna lilies, Calla lilies, Colocasia's, Crocosmia's, Anemone's, Begonia's, Freesia's, etc...
It also applies to hardy bulbs like tulips and daffodils, that you want to lift in order to move to another location or from pot to garden, garden to pot, etc...
Leave the tubers in the ground until the first frost has blackened and killed back the foliage.
Cut the stem back to 6 inches tall.
Loosen the soil in a large circle around your dahlia, about 8 inches all around the crown.
Then lift the tuber carefully from the bed with a garden fork.
Shake off the excess soil.
How to dry your corms, bulbs, rhizomes, and tubers...
After carefully lifting them...
Remove any that are wounded, mouldy, soft, or have spots of rot, toss into the compost bin.
Lay them out on newsprint in a dry, cool, airy area to dry for about two weeks.
I use a table in the carport or the greenhouse floor under a table.
A furnace room, garage or store room is a great place to spread them out to dry.
Do not expose them to moisture, rain, or direct sunshine.
Do not place right on the cold concrete floor, always use newsprint or cardboard underneath.
These dry dahlia's are now ready to be cleaned up.
Trim back the dry messy roots and the tops to about an inch long,
Clean off any remaining soil and take off any bits that have been damaged, are soft or mouldy.
Sometimes the mother plant or tuber dies and dries up and sometimes it stays alive.
This mother tuber will be a darker colour and can be removed, as it will not bloom again.
Save the fresh new tubers.
If the clump is very large, you can cut it into 2 or more new tubers,
as long as there is an eye on each piece.
(Looks pretty much the same as a potato eye)
Let the cuts dry before storing.
Glads (gladioluses, gladioli, or gladiolas)
After the first frost or once the blooms have completely finished,
cut back the stems to about 6 inches tall.
Carefully loosen the soil around the glads and lift from the ground.
Place in a cool, dry, airy place to dry.
See above for how to dry.
These glads are now ready to be cleaned up...
Removed the wee baby cormels that you see here in this picture.
Also, remove the dried up brown corm that was this years flower.
A nice, new plump corm will have formed above that dried up one, that is next years new flower.
The bigger and fatter it is, the better it will bloom.
The happiest, healthiest, biggest cormels can also be saved
and planted with the regular corms, and then lifted again in the fall.
They will size up in the garden bed, to bloom the following year.
Saving these and growing them on will provide you with great fresh stock
for great blooms each and every year.
for great blooms each and every year.
Cleaned up glad corms...
The cleaned up glads are placed into a cardboard box, an ice cream pail, paper bag,
mesh bag, some kind of storage container...
Add some peat moss, dry sand, or soil-less potting mix to the container, unless using mesh..
Store in a cool, dry, airy place.
I used to use my store room under the stairs, have also used the furnace room.
Now, I simply push my box under one of the greenhouse tables on the north side and forget about it till spring.
Every so often, pull out the box and make sure that they all are healthy.
Remove any mouldy, soft, dried out, or rotten corms.
To label your dahlias, you can simply write the name right onto the tuber with a sharpie.
This works fabulously if you have many different bulbs and want to store them all in a box together.
Or write it onto a plastic or wooden label and tuck that into the box or bag with the bulb.
I usually just write the name on the outside of the bag, box or ice cream pail.
When you check on them in late winter, early spring,
if you happen to see spindly white or pale green new growth starting,
you have no choice but to pot them up right away.
There is no way to stop the growth process once it has started.
Pop them into pots till you can get them into the ground,
and you will have bigger, better, and stronger plants.