When to plant Leeks in Mercer County, Illinois, United States
Leeks can be planted after April 28, when air temperature is consistently in a range between 40°F and 85°F and soil temperature is above 45°F.
Growing Leeks in Mercer County
Days suitable for growing Leeks in Mercer County, Illinois
Mercer County has on average 91 continious days, suitable for growing Leeks. Leeks needs on average between 80 and 150 days to mature and produce harvest.
Growing season for Leeks in Mercer County is quite short, with only 91 continious days suitable for growing, so it is really important to time your planting activities, and choose varieties with shorter time to harvest requirements.
Leeks seeds can be planted between July 29 and August 08. Planting before July 29 without any additional protection is not advised because cold streaks can damage or kill off young plant. When planting after August 08, Leeks will not have enough time to mature and produce harvest.
Growing season extention
In order to maximize chances for a good harvest of Leeks in Mercer County, some extra steps can be taken to extend growing season.
Start seeds indoors
When starting seeds indoors, it is possible to guarantee best possible conditions for young seedlings. Consistent temperature range, adequate watering and ample light (natural, supplemented with artifitial grow lights) will ensure you have strong and healthy seedlings just in time for transplanting into soil.
It takes 42 days on average for Leeks to sprout, and grow big enough to be ready for transplanting.
Mercer County has 2 distinct seasons for growing Leeks
In order to get plants ready for April 28 seeds should be started indoors bwetween March 17 and April 15
Seeds started after April 15 are not likely to mature and produce harvest.
This Leeks growing season in Mercer County is quite short, with only 68 days suitable for growth so it is really important to time your planting activities, and choose varieties with shorter time to harvest requirements.
In order to get plants ready for July 29 seeds should be started indoors bwetween June 17 and August 08
Seeds started after August 08 are not likely to mature and produce harvest.
This Leeks growing season in Mercer County is quite short, with only 91 days suitable for growth so it is really important to time your planting activities, and choose varieties with shorter time to harvest requirements.
Use a cold frame
When using a cold frame in a beggining of growing season You can protect young plants from possible temperature drops, this way growing season can start up to 2 weeks earlier.
Use an additional shading
On days, when air temperatures are expected to raise above 85°F, which is in top of tolerable range for Leeks, consider using additional shading to prevent heat shock.
| Total frost free days | 173 |
| Last frost expected date | April 28 |
| First frost expected date | October 18 |
| Dates with ideal conditions | May 18 to May 19 (2 days) May 24 to May 27 (4 days) May 29 to June 02 (5 days) September 12 September 21 to September 22 (2 days) September 24 to September 27 (4 days) September 30 to October 02 (3 days) |
| Dates with suitable conditions | April 07 to April 08 (2 days) April 13 April 22 to April 25 (4 days) April 28 to July 04 (68 days) July 06 to July 18 (13 days) July 20 to July 26 (7 days) July 29 to October 27 (91 days) November 06 November 08 to November 10 (3 days) |
| Total days ideal for growing Leeks in Mercer County | 21 |
| Total days suitable for growing Leeks in Mercer County | 190 |
| Days needed for Leeks to mature and produce harvest | 80 - 150 |
| Seed can be planted directly into soil | no |
| Seed has to be started indoors | yes |
Notable temperature facts for growing Leeks in Mercer County, Illinois
Table with days suitable to grow vegetables in Mercer County, Illinois
Tolerable temperature range for Leeks: 40°F to 85°F
| Week | Average temperature | Possible min and max temperature | Suitable for Leeks | |
|---|---|---|---|---|
| 1 | January 01 - January 03 | 23°F to 37°F | -4°F to 56°F | |
| 2 | January 04 - January 10 | 22°F to 36°F | -7°F to 54°F | |
| 3 | January 11 - January 17 | 25°F to 36°F | 2°F to 54°F | |
| 4 | January 18 - January 24 | 16°F to 31°F | -6°F to 41°F | |
| 5 | January 25 - January 31 | 12°F to 26°F | -27°F to 38°F | |
| 6 | February 01 - February 07 | 18°F to 34°F | -12°F to 53°F | |
| 7 | February 08 - February 14 | 16°F to 31°F | -7°F to 53°F | |
| 8 | February 15 - February 21 | 18°F to 36°F | -12°F to 57°F | |
| 9 | February 22 - February 28 | 24°F to 40°F | 5°F to 56°F | |
| 10 | March 01 - March 07 | 27°F to 46°F | -2°F to 64°F | |
| 11 | March 08 - March 14 | 32°F to 48°F | 11°F to 65°F | |
| 12 | March 15 - March 21 | 33°F to 50°F | 13°F to 67°F | |
| 13 | March 22 - March 28 | 36°F to 50°F | 25°F to 61°F | |
| 14 | March 29 - April 04 | 37°F to 55°F | 25°F to 75°F | |
| 15 | April 05 - April 11 | 42°F to 60°F | 29°F to 74°F | TRUE |
| 16 | April 12 - April 18 | 39°F to 57°F | 26°F to 74°F | |
| 17 | April 19 - April 25 | 42°F to 60°F | 29°F to 77°F | TRUE |
| 18 | April 26 - May 02 | 45°F to 62°F | 32°F to 78°F | TRUE |
| 19 | May 03 - May 09 | 47°F to 64°F | 38°F to 80°F | TRUE |
| 20 | May 10 - May 16 | 50°F to 67°F | 33°F to 85°F | TRUE |
| 21 | May 17 - May 23 | 55°F to 69°F | 43°F to 80°F | TRUE |
| 22 | May 24 - May 30 | 57°F to 74°F | 41°F to 84°F | TRUE |
| 23 | May 31 - June 06 | 60°F to 77°F | 49°F to 86°F | TRUE |
| 24 | June 07 - June 13 | 60°F to 78°F | 48°F to 87°F | TRUE |
| 25 | June 14 - June 20 | 62°F to 80°F | 52°F to 88°F | TRUE |
| 26 | June 21 - June 27 | 64°F to 79°F | 50°F to 90°F | TRUE |
| 27 | June 28 - July 04 | 66°F to 82°F | 57°F to 87°F | TRUE |
| 28 | July 05 - July 11 | 66°F to 80°F | 56°F to 91°F | TRUE |
| 29 | July 12 - July 18 | 65°F to 80°F | 57°F to 90°F | TRUE |
| 30 | July 19 - July 25 | 67°F to 82°F | 59°F to 91°F | TRUE |
| 31 | July 26 - August 01 | 66°F to 82°F | 58°F to 92°F | TRUE |
| 32 | August 02 - August 08 | 65°F to 80°F | 56°F to 90°F | TRUE |
| 33 | August 09 - August 15 | 65°F to 80°F | 58°F to 86°F | TRUE |
| 34 | August 16 - August 22 | 64°F to 79°F | 56°F to 87°F | TRUE |
| 35 | August 23 - August 29 | 67°F to 82°F | 57°F to 92°F | TRUE |
| 36 | August 30 - September 05 | 62°F to 78°F | 53°F to 86°F | TRUE |
| 37 | September 06 - September 12 | 61°F to 76°F | 53°F to 87°F | TRUE |
| 38 | September 13 - September 19 | 60°F to 76°F | 50°F to 84°F | TRUE |
| 39 | September 20 - September 26 | 58°F to 73°F | 46°F to 86°F | TRUE |
| 40 | September 27 - October 03 | 56°F to 72°F | 43°F to 83°F | TRUE |
| 41 | October 04 - October 10 | 51°F to 66°F | 37°F to 78°F | TRUE |
| 42 | October 11 - October 17 | 47°F to 62°F | 36°F to 76°F | TRUE |
| 43 | October 18 - October 24 | 45°F to 61°F | 30°F to 76°F | TRUE |
| 44 | October 25 - October 31 | 39°F to 51°F | 28°F to 67°F | TRUE |
| 45 | November 01 - November 07 | 38°F to 55°F | 23°F to 69°F | |
| 46 | November 08 - November 14 | 37°F to 51°F | 10°F to 70°F | |
| 47 | November 15 - November 21 | 33°F to 48°F | 19°F to 64°F | |
| 48 | November 22 - November 28 | 31°F to 45°F | 12°F to 55°F | |
| 49 | November 29 - December 05 | 30°F to 44°F | 21°F to 57°F | |
| 50 | December 06 - December 12 | 29°F to 43°F | 17°F to 57°F | |
| 51 | December 13 - December 19 | 28°F to 39°F | 16°F to 67°F | |
| 52 | December 20 - December 26 | 27°F to 41°F | -9°F to 57°F | |
| 53 | December 27 - December 31 | 28°F to 41°F | 1°F to 59°F |
Days with suitable temperature for growing Leeks in Mercer County, Illinois
All data is provided “as is” without warranty or any representation of accuracy, timeliness or completeness.
© 2024 Plan and Plant. All rights reserved.
Average daily temperatures were calculated using
