When to plant Rhubarb in Johnson County, Iowa, United States
Rhubarb can be planted after April 29, when air temperature is consistently in a range between 40°F and 80°F and soil temperature is above 45°F.
Growing Rhubarb in Johnson County
Days suitable for growing Rhubarb in Johnson County, Iowa
Johnson County has on average 61 continious days, suitable for growing Rhubarb. Rhubarb needs on average between 56 and 70 days to mature and produce harvest.
Growing season for Rhubarb in Johnson County is quite short, with only 61 continious days suitable for growing, so it is really important to time your planting activities, and choose varieties with shorter time to harvest requirements.
Rhubarb seeds can be planted between April 29 and May 03. Planting before April 29 without any additional protection is not advised because cold streaks can damage or kill off young plant. When planting after May 03, Rhubarb will not have enough time to mature and produce harvest.
Growing season extention
In order to maximize chances for a good harvest of Rhubarb in Johnson 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 Rhubarb to sprout, and grow big enough to be ready for transplanting.
Johnson County has 2 distinct seasons for growing Rhubarb
In order to get plants ready for April 29 seeds should be started indoors bwetween March 18 and April 19
Seeds started after April 19 are not likely to mature and produce harvest.
This Rhubarb growing season in Johnson County is quite short, with only 61 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 August 31 seeds should be started indoors bwetween July 20 and August 07
Seeds started after August 07 are not likely to mature and produce harvest.
This Rhubarb growing season in Johnson County is quite short, with only 47 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 80°F, which is in top of tolerable range for Rhubarb, 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 | |
| Dates with suitable conditions | April 23 April 29 to June 28 (61 days) July 01 to July 02 (2 days) July 07 to July 13 (7 days) July 16 to July 17 (2 days) July 22 July 31 August 02 August 05 August 07 to August 09 (3 days) August 12 to August 18 (7 days) August 21 August 31 to October 16 (47 days) October 18 to October 26 (9 days) November 06 November 09 to November 10 (2 days) |
| Total days ideal for growing Rhubarb in Johnson County | 0 |
| Total days suitable for growing Rhubarb in Johnson County | 147 |
| Days needed for Rhubarb to mature and produce harvest | 56 - 70 |
| Seed can be planted directly into soil | no |
| Seed has to be started indoors | yes |
Notable temperature facts for growing Rhubarb in Johnson County, Iowa
Table with days suitable to grow vegetables in Johnson County, Iowa
Tolerable temperature range for Rhubarb: 40°F to 80°F
| Week | Average temperature | Possible min and max temperature | Suitable for Rhubarb | |
|---|---|---|---|---|
| 1 | January 01 - January 03 | 19°F to 34°F | -7°F to 50°F | |
| 2 | January 04 - January 10 | 20°F to 34°F | -9°F to 52°F | |
| 3 | January 11 - January 17 | 23°F to 35°F | 0°F to 54°F | |
| 4 | January 18 - January 24 | 13°F to 28°F | -11°F to 38°F | |
| 5 | January 25 - January 31 | 9°F to 23°F | -29°F to 37°F | |
| 6 | February 01 - February 07 | 15°F to 31°F | -13°F to 51°F | |
| 7 | February 08 - February 14 | 14°F to 29°F | -9°F to 51°F | |
| 8 | February 15 - February 21 | 15°F to 33°F | -11°F to 55°F | |
| 9 | February 22 - February 28 | 21°F to 37°F | -2°F to 56°F | |
| 10 | March 01 - March 07 | 24°F to 44°F | -9°F to 61°F | |
| 11 | March 08 - March 14 | 30°F to 46°F | 10°F to 65°F | |
| 12 | March 15 - March 21 | 32°F to 49°F | 11°F to 67°F | |
| 13 | March 22 - March 28 | 35°F to 50°F | 23°F to 61°F | |
| 14 | March 29 - April 04 | 35°F to 54°F | 24°F to 71°F | |
| 15 | April 05 - April 11 | 41°F to 60°F | 26°F to 73°F | TRUE |
| 16 | April 12 - April 18 | 37°F to 55°F | 23°F to 74°F | |
| 17 | April 19 - April 25 | 41°F to 59°F | 27°F to 75°F | TRUE |
| 18 | April 26 - May 02 | 44°F to 62°F | 29°F to 78°F | TRUE |
| 19 | May 03 - May 09 | 46°F to 63°F | 37°F to 80°F | TRUE |
| 20 | May 10 - May 16 | 49°F to 67°F | 32°F to 84°F | TRUE |
| 21 | May 17 - May 23 | 53°F to 68°F | 41°F to 79°F | TRUE |
| 22 | May 24 - May 30 | 56°F to 72°F | 40°F to 83°F | TRUE |
| 23 | May 31 - June 06 | 58°F to 76°F | 47°F to 83°F | TRUE |
| 24 | June 07 - June 13 | 59°F to 76°F | 47°F to 86°F | TRUE |
| 25 | June 14 - June 20 | 61°F to 79°F | 53°F to 89°F | TRUE |
| 26 | June 21 - June 27 | 62°F to 78°F | 48°F to 90°F | TRUE |
| 27 | June 28 - July 04 | 65°F to 81°F | 57°F to 86°F | |
| 28 | July 05 - July 11 | 65°F to 79°F | 54°F to 88°F | TRUE |
| 29 | July 12 - July 18 | 64°F to 80°F | 56°F to 89°F | TRUE |
| 30 | July 19 - July 25 | 65°F to 81°F | 58°F to 92°F | |
| 31 | July 26 - August 01 | 65°F to 81°F | 57°F to 90°F | |
| 32 | August 02 - August 08 | 63°F to 79°F | 55°F to 90°F | TRUE |
| 33 | August 09 - August 15 | 63°F to 79°F | 56°F to 86°F | TRUE |
| 34 | August 16 - August 22 | 62°F to 78°F | 54°F to 88°F | TRUE |
| 35 | August 23 - August 29 | 66°F to 81°F | 57°F to 93°F | |
| 36 | August 30 - September 05 | 61°F to 77°F | 51°F to 89°F | TRUE |
| 37 | September 06 - September 12 | 59°F to 75°F | 48°F to 87°F | TRUE |
| 38 | September 13 - September 19 | 59°F to 76°F | 48°F to 83°F | TRUE |
| 39 | September 20 - September 26 | 57°F to 72°F | 46°F to 85°F | TRUE |
| 40 | September 27 - October 03 | 56°F to 71°F | 41°F to 85°F | TRUE |
| 41 | October 04 - October 10 | 50°F to 66°F | 35°F to 78°F | TRUE |
| 42 | October 11 - October 17 | 45°F to 61°F | 34°F to 74°F | TRUE |
| 43 | October 18 - October 24 | 44°F to 60°F | 28°F to 76°F | TRUE |
| 44 | October 25 - October 31 | 37°F to 50°F | 27°F to 68°F | |
| 45 | November 01 - November 07 | 37°F to 54°F | 21°F to 69°F | |
| 46 | November 08 - November 14 | 35°F to 50°F | 9°F to 69°F | |
| 47 | November 15 - November 21 | 32°F to 47°F | 18°F to 64°F | |
| 48 | November 22 - November 28 | 30°F to 44°F | 15°F to 55°F | |
| 49 | November 29 - December 05 | 29°F to 43°F | 19°F to 54°F | |
| 50 | December 06 - December 12 | 28°F to 41°F | 15°F to 56°F | |
| 51 | December 13 - December 19 | 25°F to 37°F | 13°F to 68°F | |
| 52 | December 20 - December 26 | 24°F to 39°F | -10°F to 57°F | |
| 53 | December 27 - December 31 | 25°F to 38°F | -5°F to 58°F |
Days with suitable temperature for growing Rhubarb in Johnson County, Iowa
All data is provided “as is” without warranty or any representation of accuracy, timeliness or completeness.
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Average daily temperatures were calculated using
