It's only the beginning of August, but time is wasting for sowing seeds now to harvest greens and other vegetables up to—and after—frost. Below is a customized version of a useful calculator provided by Johnny's Selected Seeds available here. We've customized it for Evanston, broken out the seed starting and planting out dates, and then sorted it by seed starting date.
It assumes the hard-frost date for Evanston (28 degrees, 10 year median) from:
http://www.isws.illinois.edu/atmos/statecli/Frost/frost.htm
Note that crops marked TP need to be started 4 weeks ahead and planted out on the date shown in the last column.
| Fall-Planting Calculator | ||||
| This calculator will help you determine the planting date for crops that will be planted outside, without additional protection, for harvest in autumn. All are crops that tolerate frost and taste great in cool weather. If planting in an unheated hoophouse or low tunnel, you can plant 2-3 weeks later than the date recommended. If planting inside a hoophouse with an additional layer of hoops and row cover above the crop, you can plant 4-5 weeks later. | ||||
| Enter your average first frost date: |
10/21 | |||
| Crop** | direct or transplant date | note | When to Plant Out | When to start |
| Celeriac | TP | 15-Jun | 18-May | |
| Brussels Sprouts | TP | *** | 23-Jun | 26-May |
| Cabbage, storage | TP | 28-Jun | 31-May | |
| Leeks | TP | 28-Jun | 31-May | |
| Celery | TP | 5-Jul | 7-Jun | |
| Parsnips | DS | 8-Jun | 8-Jun | |
| Cabbage, fresh eating | TP | 23-Jul | 25-Jun | |
| Collards | TP | 25-Jul | 27-Jun | |
| Broccoli | TP | 29-Jul | 1-Jul | |
| Cauliflower | TP | 30-Jul | 2-Jul | |
| Chicory - Radicchio | TP | 2-Aug | 5-Jul | |
| Fennel | DS | 5-Jul | 5-Jul | |
| Peas | DS | frost-sensitive | 11-Jul | 11-Jul |
| Cabbage, Chinese | TP | 15-Aug | 18-Jul | |
| Rutabaga | DS | 23-Jul | 23-Jul | |
| Chicory - Endive, Escarole | TP | 22-Aug | 25-Jul | |
| Kale | DS | 25-Jul | 25-Jul | |
| Carrots | DS | 27-Jul | 27-Jul | |
| Onions | DS | 2-Aug | 2-Aug | |
| Beets | DS | 9-Aug | 9-Aug | |
| Greens, Asian, full size | DS | 14-Aug | 14-Aug | |
| Lettuce, heads | DS | 14-Aug | 14-Aug | |
| Radish, Daikon | DS | 17-Aug | 17-Aug | |
| Swiss chard, bunching | DS | 18-Aug | 18-Aug | |
| Turnip, purple top | DS | 18-Aug | 18-Aug | |
| Kohlrabi | DS | 22-Aug | 22-Aug | |
| Lettuce, baby | DS | 24-Aug | 24-Aug | |
| Spinach | DS | 28-Aug | 28-Aug | |
| Turnips, salad | DS | 29-Aug | 29-Aug | |
| Radish, round | DS | 15-Sep | 15-Sep | |
| *Dates are the same from year to year, but this table requires a year for computation simplicity. | ||||
| **The date calculated is the date to plant outdoors; crops that should be direct sown are marked (DS). Those marked (TP) should be set out as transplants on the date shown, so seeds should be started four weeks before the planting date. | ||||
| ***Brussels sprouts should mature after frost, so no additional time is added for harvest period or fall factor. | ||||
| The calculator uses this formula: Days to Maturity (we used varieties recommended for fall/winter) + Average harvest period + Fall Factor (takes into account the slow growth that results from cool weather and short days in fall, and amounts to about two weeks.) = Days to count back from first frost date |
||||
| © JOHNNY SELECTED SEEDS. ALL RIGHTS RESERVED | 955 BENTON AVENUE WINSLOW, MAINE 04901 JOHNNY'S SELECTED SEEDS IS A PRIVATELY HELD, EMPLOYEE-OWNED COMPANY |
||||