When to plant dahlias
tender tuber
The short answer
Dahlias are planted out after the last frost. Start them indoors 6 to 8 weeks before the last frost.
Zone 5: plant out from Apr 30. Zone 7: plant out from Apr 5. Zone 9: plant out from Feb 20. See every zone or your state.
When to plant dahlias by USDA zone
Dates are worked out from each zone’s typical last frost, using the number of weeks the cited extension services give. Find your zone on the zone map. Zones 11 and above are frost-free, so timing there depends on heat and rain instead.
| Zone | Typical last frost | Pot tubers indoors | Plant out |
|---|---|---|---|
| Zone 3 | May 15 | Mar 20 – Apr 3 | from May 15 |
| Zone 4 | May 10 | Mar 15 – Mar 29 | from May 10 |
| Zone 5 | Apr 30 | Mar 5 – Mar 19 | from Apr 30 |
| Zone 6 | Apr 15 | Feb 18 – Mar 4 | from Apr 15 |
| Zone 7 | Apr 5 | Feb 8 – Feb 22 | from Apr 5 |
| Zone 8 | Mar 20 | Jan 23 – Feb 6 | from Mar 20 |
| Zone 9 | Feb 20 | Dec 26 – Jan 9 | from Feb 20 |
| Zone 10 | Jan 30 | Dec 5 – Dec 19 | from Jan 30 |
Rule used: plant out after the last frost; pot tubers indoors 6 to 8 weeks before the last frost.
When to plant dahlias in your state
Same rule, applied to each state’s typical last spring frost. States marked * span very different climates, so use your own frost date for the exact day - click a state for its frost dates.
| State | Typical last frost | Pot tubers indoors | Plant out |
|---|---|---|---|
| Alabama | Mar 25 | Jan 28 – Feb 11 | from Mar 25 |
| Alaska * | May 17 | Mar 22 – Apr 5 | from May 17 |
| Arizona * | Mar 15 | Jan 18 – Feb 1 | from Mar 15 |
| Arkansas | Apr 3 | Feb 6 – Feb 20 | from Apr 3 |
| California * | Feb 20 | Dec 26 – Jan 9 | from Feb 20 |
| Colorado | May 5 | Mar 10 – Mar 24 | from May 5 |
| Connecticut | Apr 25 | Feb 28 – Mar 14 | from Apr 25 |
| Delaware | Apr 14 | Feb 17 – Mar 3 | from Apr 14 |
| District of Columbia | Apr 10 | Feb 13 – Feb 27 | from Apr 10 |
| Florida | Feb 12 | Dec 18 – Jan 1 | from Feb 12 |
| Georgia | Mar 25 | Jan 28 – Feb 11 | from Mar 25 |
| Idaho | May 10 | Mar 15 – Mar 29 | from May 10 |
| Illinois | Apr 20 | Feb 23 – Mar 9 | from Apr 20 |
| Indiana | Apr 24 | Feb 27 – Mar 13 | from Apr 24 |
| Iowa | Apr 25 | Feb 28 – Mar 14 | from Apr 25 |
| Kansas | Apr 15 | Feb 18 – Mar 4 | from Apr 15 |
| Kentucky | Apr 18 | Feb 21 – Mar 7 | from Apr 18 |
| Louisiana | Mar 5 | Jan 8 – Jan 22 | from Mar 5 |
| Maine | May 14 | Mar 19 – Apr 2 | from May 14 |
| Maryland | Apr 14 | Feb 17 – Mar 3 | from Apr 14 |
| Massachusetts | Apr 24 | Feb 27 – Mar 13 | from Apr 24 |
| Michigan | May 10 | Mar 15 – Mar 29 | from May 10 |
| Minnesota | May 6 | Mar 11 – Mar 25 | from May 6 |
| Mississippi | Mar 20 | Jan 23 – Feb 6 | from Mar 20 |
| Missouri | Apr 15 | Feb 18 – Mar 4 | from Apr 15 |
| Montana | May 15 | Mar 20 – Apr 3 | from May 15 |
| Nebraska | Apr 30 | Mar 5 – Mar 19 | from Apr 30 |
| Nevada * | Apr 20 | Feb 23 – Mar 9 | from Apr 20 |
| New Hampshire | May 13 | Mar 18 – Apr 1 | from May 13 |
| New Jersey | Apr 20 | Feb 23 – Mar 9 | from Apr 20 |
| New Mexico * | Apr 20 | Feb 23 – Mar 9 | from Apr 20 |
| New York * | May 1 | Mar 6 – Mar 20 | from May 1 |
| North Carolina | Apr 5 | Feb 8 – Feb 22 | from Apr 5 |
| North Dakota | May 15 | Mar 20 – Apr 3 | from May 15 |
| Ohio | Apr 25 | Feb 28 – Mar 14 | from Apr 25 |
| Oklahoma | Apr 1 | Feb 4 – Feb 18 | from Apr 1 |
| Oregon * | Apr 20 | Feb 23 – Mar 9 | from Apr 20 |
| Pennsylvania | May 1 | Mar 6 – Mar 20 | from May 1 |
| Rhode Island | Apr 25 | Feb 28 – Mar 14 | from Apr 25 |
| South Carolina | Mar 25 | Jan 28 – Feb 11 | from Mar 25 |
| South Dakota | May 10 | Mar 15 – Mar 29 | from May 10 |
| Tennessee | Apr 10 | Feb 13 – Feb 27 | from Apr 10 |
| Texas * | Mar 15 | Jan 18 – Feb 1 | from Mar 15 |
| Utah | May 5 | Mar 10 – Mar 24 | from May 5 |
| Vermont | May 14 | Mar 19 – Apr 2 | from May 14 |
| Virginia | Apr 15 | Feb 18 – Mar 4 | from Apr 15 |
| Washington * | Apr 20 | Feb 23 – Mar 9 | from Apr 20 |
| West Virginia | May 5 | Mar 10 – Mar 24 | from May 5 |
| Wisconsin | May 10 | Mar 15 – Mar 29 | from May 10 |
| Wyoming | May 20 | Mar 25 – Apr 8 | from May 20 |
What extension services say
- Pot dahlia tubers indoors 6 to 8 weeks before the date you intend to plant them outside. Iowa State University Extension ↗
- Iowa plants dahlias outdoors in mid-May in central Iowa, about a week earlier in southern Iowa and a week later in the north, to avoid frost or freeze damage. Iowa State University Extension ↗
- Tender bulbs such as dahlias are planted in spring for summer bloom, outdoors once the danger of frost has passed. University of Minnesota Extension ↗
- Growing from seed instead of tubers: Colorado's table says to start dahlia seed indoors 8 weeks before the average frost-free date (6 weeks in a cold frame). Colorado State University Extension ↗
- Minnesota's seed-starting calendar puts dahlia seed in early March, about 10-11 weeks indoors. University of Minnesota Extension ↗
The table counts the 6-8 weeks back from the zone's typical last frost date, which is the earliest sensible outdoor date. If you plant out later, pot up later by the same amount.
Questions gardeners ask
When do you plant dahlias?
Outdoors after the danger of frost has passed. Iowa State gives mid-May for central Iowa as its example. To get a head start, pot the tubers indoors 6 to 8 weeks before your planned outdoor date.
How deep do you plant dahlia tubers?
Iowa State says to dig holes about 6 to 8 inches deep and lay the tuber horizontally, with the shoots appearing in about two weeks.
Can you plant dahlias too early?
Yes. Iowa State times outdoor planting to avoid frost or freeze damage, so wait until the last frost has passed.
Sources
- Iowa State University Extension: Planting and Caring for Tender Perennials
- University of Minnesota Extension: Planting bulbs, tubers and rhizomes
- Colorado State University Extension: Growing Annual Plants from Seed
- University of Minnesota Extension: Starting seeds indoors
Extension advice is local to the state that wrote it. Where the sources differ, both are shown. Dates in the tables are estimates from typical frost dates; your garden’s own last frost can differ by a week or more. How we source data.