Welcome to my blog

I like to know if anyone is looking at my blog so please comment, if you can think of something, to say or e-mail me at madsmckeever@eircom.net

Tuesday, March 4, 2014

Soil temperature is the best indicator of when it is the right time to sow vegetables


Norfolk farmers allegedly dropped their trousers, and sat on the soil to see if it was warm enough to sow crops. A soil thermometer is probably as accurate.  

Below are the Met Eireann soil temperature figures for Sherkin Island which is the closest weather station to Brown Envelope Seeds. Although soil temperatures differ a little from year to year, especially in spring and autumn, they are fairly predictable between May and September differing by only a degree or two on average. Met Eireann statistics can be found here By looking up the nearest station to you, you can see when soil temperature is suitable for the sowing of crops in your area, or you can use a soil thermometer - or you can use the Norfolk method. 

Mean 10cm soil temperature for Sherkin Island

Year
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
2014
7.0
6.7
7.0









6.9
2013
7.5
6.8
6.3
8.9
12.3
15.5
18.8
17.6
15.3
13.7
8.5
8.0
11.6
2012
9.0
9.0
10.0
9.7
12.6
15.2
16.1
16.8
14.8
11.5
8.4
7.7
11.7
2011
5.5
8.1
8.5
12.6
13.4
15.7
16.7
16.2
14.5
12.5
10.9
8.1
11.9


The figures for Mullingar show more variation than Sherkin which is to be expected, as Mullingar is further inland and both higher summer and lower winter temperatures occur, as the temperature of the sea buffers the climatic changes near the coast. 

Mean 10cm soil temperature for Mullingar

Year
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Annual
2014
4.4
5.0
5.2









4.7
2013
4.7
4.6
4.8
8.3
12.6
16.6
20.1
18.1
15.0
12.5
7.2
6.0
10.9
2012
6.1
6.7
8.9
9.7
13.4
15.8
17.3
17.7
14.6
10.4
6.8
4.5
11.0
2011
2.7
6.0
7.1
12.3
13.0
15.5
17.4
16.3
14.4
12.1
9.2
5.1
10.9


Broad beans, rocket, kale, parsnips, peas, radishes and spinach can germinate at temperatures as low as 5ºC but may take up to a month to do so. At 10ºC a higher proportion of seeds will germinated and maximum germination of crops will be a lot faster than at 5ºC. As soil temperature reach 10ºC sometime in April or May crops such as beet, cabbage, lettuce, onions and leeks, will germinate but growth will be slow and the plants will be subject to more pressure from slugs and other leaf eating pests.  At 15ºC degrees, french beans, carrots and sweetcorn will germinate, and plant growth will be a lot faster,  so crops will have a better chance of competing with weeds. Soil temperatures in a polytunnel will be several degrees higher and so plants started under cover will get a head start. Corn, courgettes, pumpkins, cucumbers, tomatoes and aubergines are happier at soil temperatures of 20ºC or more and will do a lot better under cover. In a good summer they will have a chance outside and by choosing cold tolerant short season varieties chances of success are improved. 

The next table shows the germination of different vegetables at different temperatures. 
The number in brackets is the number of days to reach the level of germination. Most seeeds will germinate between 15 and 25



Crops
0ºC
5ºC
10ºC
15ºC
20ºC
25ºC
30ºC
35ºC
Asparagus
  0
  0
 61(53)
 80(24)
 88(15)
 95(10)
 79(12)
 37(19)
Beans, lima
  0
  0
  1
 52(31)
 82(18)
 90(7)
 88(7)
  2
Beans, snap
  0
  0
  1
 97(16)
 90(11)
 97(8)
 47(6)
 39(6)
Beets
  0
 53(42)
 72(17)
 88(10)
 90(6)
 97(5)
 89(5)
 35(5)
Cabbage
  0
 27
 78(15)
 93(9)
  0(6)
 99(5)
  0(4)
  0
Carrots
  0
 48(51)
 93(17)
 95(10)
 96(7)
 96(6)
 95(6)
 74(9)
Cauliflower
  0
  0
 58(20)
 60(10)
  0(6)
 63(5)
 45(5)
  0
Celery
  0
 72(41)
 70(16)
 40(12)
 97(7)
 65
  0
  0
Cucumber
  0
  0
  0
 95(13)
 99(6)
 99(4)
 99(3)
 99(3)
Eggplant
  0
  0
  0
  0
 21(13)
 53(8)
 60(5)
  0
Lettuce
 98(49)
 98(15)
 98(7)
 99(4)
 99(3)
 99(2)
 12(3)
  0
Muskmelon
  0
  0
  0
  0
 38(8)
 94(4)
 90(3)
  0
Okra
  0
  0
  0
 74(27)
 89(17)
 92(13)
 88(7)
 85(6)
Onions
 90(136)
 98(31)
 98(13)
 98(7)
 99(5)
 97(4)
 91(4)
 73(13)
Parsley
  0
  0
 63(29)
  0(17)
 69(14)
 64(13)
 50(12)
  0
Parsnips
 82(172)
 87(57)
 79(27)
 85(19)
 89(14)
 77(15)
 51(32)
  1
Peas
  0
 89(36)
 94(14)
 93(9)
 93(8)
 94(6)
 86(6)
  0
Peppers
  0
  0
  1
 70(25)
 96(13)
 98(8)
 95(8)
 70(9)
Radish
  0
 42(29)
 76(11)
 97(6)
 95(4)
 97(4)
 95(3)
  0
Spinach
 83(63)
 96(23)
 91(12)
 82(7)
 52(6)
 28(5)
 32(6)
  0
Sweet Corn
  0
  0
 47(22)
 97(12)
 97(7)
 98(4)
 91(4)
 88(3)
Tomatoes
  0
  0
 82(43)
 98(14)
 98(8)
 97(6)
 83(6)
 46(9)
Turnips
  1
 14
 79(5)
 98(3)
 99(2)
100(1)
 99(1)
 99(1)
Watermelon
  0
  0
  0
 17
 94(12)
 90(5)
 92(4)
 96(3)

I hope this will help people decide when to sow their seeds. 
Posted by at 3 comments:

Wednesday, January 29, 2014

Useful table of germination temperatures

Those of you who remember when summers were always sunny, and potatoes came in stones, will be able to convert Farrenheit to Centigrade, and be able to understand this. For the youth, 68 is the temperature of your living room when you are in need of a jumper, but not a coat. 32 is the temperature your shots come at, so you can't taste them, and 95 is almost body temperature. 

 I lifted this table off the internet somewhere and I apologise to whoever put it there for not acknowledging them.  It indicates what temperature seeds germinate best at. It is important to note that seeds like tomatoes, cucumbers, etc, need a nice warm place and will not come up in a cold greenhouse in early spring. Likewise, some seeds such as those of lettuce and spinach, land cress and winter purslane will not germinate at high temperatures and need to be chilled for a while. 


Crops
32ºF
41ºF
50ºF
59ºF
68ºF
77ºF
86ºF
95ºF
Asparagus
  0
  0
 61(53)
 80(24)
 88(15)
 95(10)
 79(12)
 37(19)
Beans, lima
  0
  0
  1
 52(31)
 82(18)
 90(7)
 88(7)
  2
Beans, snap
  0
  0
  1
 97(16)
 90(11)
 97(8)
 47(6)
 39(6)
Beets
  0
 53(42)
 72(17)
 88(10)
 90(6)
 97(5)
 89(5)
 35(5)
Cabbage
  0
 27
 78(15)
 93(9)
  0(6)
 99(5)
  0(4)
  0
Carrots
  0
 48(51)
 93(17)
 95(10)
 96(7)
 96(6)
 95(6)
 74(9)
Cauliflower
  0
  0
 58(20)
 60(10)
  0(6)
 63(5)
 45(5)
  0
Celery
  0
 72(41)
 70(16)
 40(12)
 97(7)
 65
  0
  0
Cucumber
  0
  0
  0
 95(13)
 99(6)
 99(4)
 99(3)
 99(3)
Eggplant
  0
  0
  0
  0
 21(13)
 53(8)
 60(5)
  0
Lettuce
 98(49)
 98(15)
 98(7)
 99(4)
 99(3)
 99(2)
 12(3)
  0
Muskmelon
  0
  0
  0
  0
 38(8)
 94(4)
 90(3)
  0
Okra
  0
  0
  0
 74(27)
 89(17)
 92(13)
 88(7)
 85(6)
Onions
 90(136)
 98(31)
 98(13)
 98(7)
 99(5)
 97(4)
 91(4)
 73(13)
Parsley
  0
  0
 63(29)
  0(17)
 69(14)
 64(13)
 50(12)
  0
Parsnips
 82(172)
 87(57)
 79(27)
 85(19)
 89(14)
 77(15)
 51(32)
  1
Peas
  0
 89(36)
 94(14)
 93(9)
 93(8)
 94(6)
 86(6)
  0
Peppers
  0
  0
  1
 70(25)
 96(13)
 98(8)
 95(8)
 70(9)
Radish
  0
 42(29)
 76(11)
 97(6)
 95(4)
 97(4)
 95(3)
  0
Spinach
 83(63)
 96(23)
 91(12)
 82(7)
 52(6)
 28(5)
 32(6)
  0
Sweet Corn
  0
  0
 47(22)
 97(12)
 97(7)
 98(4)
 91(4)
 88(3)
Tomatoes
  0
  0
 82(43)
 98(14)
 98(8)
 97(6)
 83(6)
 46(9)
Turnips
  1
 14
 79(5)
 98(3)
 99(2)
100(1)
 99(1)
 99(1)
Watermelon
  0
  0
  0
 17
 94(12)
 90(5)
 92(4)
 96(3)


The number in brackets is the number of days it took to reach this level of germination. So, as you can see in the picture, the tomatoes (on the left) are up before the peppers (on the right). I hope this helps.
Posted by at 3 comments:
Subscribe to: Posts (Atom)