| Plant | Zone 5a | Zone 5b |
|---|---|---|
| Zinnia | Plant outside: May 10 to Jun 14 Start seeds indoors: around Apr 12 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Apr 10 |
| French marigold | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 29 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Mar 27 |
| Petunia | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 1 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Feb 27 |
| Cosmos | Plant outside: May 10 to Jun 14 | Plant outside: May 8 to Jun 12 |
| Sunflower | Plant outside: May 10 to Jun 14 | Plant outside: May 8 to Jun 12 |
| Impatiens | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 15 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Mar 13 |
| Wax begonia | Plant outside: May 10 to Jun 14 Start seeds indoors: around Feb 15 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Feb 13 |
| Zonal geranium | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 15 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Mar 13 |
| Snapdragon | Plant outside: Apr 5 to May 3 Start seeds indoors: around Feb 8 Fall planting: Aug 17 to Sep 14 | Plant outside: Apr 3 to May 1 Start seeds indoors: around Feb 6 Fall planting: Aug 22 to Sep 19 |
| Pansy | Plant outside: Apr 5 to May 3 Start seeds indoors: around Jan 25 Fall planting: Aug 17 to Sep 14 | Plant outside: Apr 3 to May 1 Start seeds indoors: around Jan 23 Fall planting: Aug 22 to Sep 19 |
| Sweet alyssum | Plant outside: Apr 5 to May 3 Fall planting: Aug 17 to Sep 14 | Plant outside: Apr 3 to May 1 Fall planting: Aug 22 to Sep 19 |
| Celosia | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 29 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Mar 27 |
| Scarlet sage | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 15 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Mar 13 |
| Lantana | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 1 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Feb 27 |
| Madagascar periwinkle | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 1 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Feb 27 |
| Nasturtium | Plant outside: May 10 to Jun 14 | Plant outside: May 8 to Jun 12 |
| Sweet pea | Plant outside: Apr 5 to May 3 Fall planting: Aug 17 to Sep 14 | Plant outside: Apr 3 to May 1 Fall planting: Aug 22 to Sep 19 |
| Larkspur | Plant outside: Apr 5 to May 3 Fall planting: Aug 17 to Sep 14 | Plant outside: Apr 3 to May 1 Fall planting: Aug 22 to Sep 19 |
| Pot marigold | Plant outside: Apr 5 to May 3 Fall planting: Aug 17 to Sep 14 | Plant outside: Apr 3 to May 1 Fall planting: Aug 22 to Sep 19 |
| Coleus | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 1 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Feb 27 |
| Garden verbena | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 15 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Mar 13 |
| Spider flower | Plant outside: May 10 to Jun 14 | Plant outside: May 8 to Jun 12 |
| Floss flower | Plant outside: May 10 to Jun 14 Start seeds indoors: around Mar 15 | Plant outside: May 8 to Jun 12 Start seeds indoors: around Mar 13 |
| Moss rose | Plant outside: May 10 to Jun 14 | Plant outside: May 8 to Jun 12 |
Zones measure winter cold, not season length, so your own frost dates can be a week or two off the zone median. Look up your frost dates by ZIP code, or read all about zone 5a.
Hardiness ranges, light and size are typical figures from university extension services and botanic garden plant records; a named variety can differ, so check its tag. Planting dates come from each zone's median frost dates (NOAA 1991 to 2020 climate normals) and the timing rules in how we check.