When to plant dwarf dahlia tubers in zone 4?

[zxcvbob]

Do they need to wait until the soil is warm, or plant as soon as it thaws and nights are usually above freezing? Or do they need to be started indoors in pots, then set out like tender annuals?

I almost bought a dozen bedding dahlias at Sam's Club today, but then thought it might be too early. I know they are day-length sensitive; that's why I've never tried starting 'em from seeds (days are long while it's still cold up here)

Thanks, Bob, in southern MN

[David E. Ross]

Dahlias are actually tropical or towards the tropical end of subtropical. Plant them about a month after the date of when the last expected frost might occur.

In the fall as they die down, dig up the tubers and store them in damp (not wet) sand, sawdust, or peat moss in a place where temperatures might be quite cool but never freezing. Cut the stalks to about 2 inches from the tubers, but do not divide them until you are ready to plant them again. When it is time to plant again next year, cut the stub of the stalk vertically to separate the tubers so that each tuber has a piece of the stalk. The new growth buds will be where the stalk meets the tuber.

[zxcvbob]

Thanks David. I know *how* to dig and store them, but I've never been successful at it up here. 7+ months is just too long for me to keep the dormant tubers from either drying out or rotting.

Wife buys a few 4" pots of dwarf dahlias every year, so I thought I might try planting tubers and see what happens.

So that would be end of June... ;-) (I'm really not exaggerating much)

Bob

[Moe DeLoughan]

If you want them to bloom before later summer/fall, start them indoors in pots right now.

If you live in the Twin Cities area or south of that, you can plant them outdoors around the end of May. Average last frost date falls within the first half of May, depending on specific location.

Also, if you're in southern Minnesota you're almost certainly in zone

1. Local rosarian Jack Flaker wrote an article about the changing climate zones in Minnesota and how the USDA documentation is outdated. You can read it here:

[Brooklyn1]

As with other plants usually dahlias are sold in their correct planting zone, and almost always directions are on the packaging material. There's plenty of info on the net, I suggest checking several sites to glean the facts that best pertain to your parameters:

[paullypaul]

Why not just go for it and grow them in the house like me. When they are big enough then hopefully the weather will be warm enough for them to carry on. My indoors nursery in following vid :)

[peas_22]

Dahlias are summer blooming tubers that are generally only hardy in USDA zones 7-11. Almost of the country, Dahlias must be planted each spring and then cut back and dug each fall after the first killing frost.

Dahlia plants grow and bloom best in full sun, tolerate most soil types, but prefer a sandy, well drained, slightly acidic soil with a pH of 6.2-

6.5.

If your soil is heavy or clay, adding sand and peat moss will help to lighten it.