What's The Weather for Salad?

NB I'm using that sparkly gold notebook to record everything and make notes about my 52 Week Salad Challenge :)

I've been looking into my local climate data this week to get an idea of when I can sensibly switch from indoor growing to outside. Previously I've found I can usually grow plenty of salad for us from April/May to October/November depending on how the weather's doing in a particular year.

I've looked at the Met Office website and printed off the 1971-2000 average climate information for my local area. I printed both the Lyneham and Boscombe Down weather station data because whilst Lyneham is the closest, it's quite a bit higher than where we are. In reality it turned out there's little to choose between them.

Many of our salad crops, particularly lettuce need 100C in order to germinate and will have some growth from around 50C. Therefore these are 2 key temperatures to look for in the climate data. I also looked at which months don't have an air frost on average because this gives an idea of when crops can be safely left without any protection.

From the data I found on average:
  • Months max temperature exceeds 50C: All year
  • Months min temperature exceeds 50C: May-Oct
  • Months max temperature exceeds 100C : Apr-Nov
  • Months min temperature exceeds 100C: Jun-Jul
  • Months with no air frost: Jun-Sept (and May and October have less than 1 night's air frost on average)
From this information I can see:
  • There is the potential for outside growth most if not all year - albeit this will be limited in the winter and crops will need protection
  • My ability to grow crops outside from April-May to Oct-November fits with when the average maximum daily temperature exceeds 100C. Also, seed sown outdoors at this time will germinate - indoor or protected sowing is needed in the other months
  • I can confidently grow without protection from June until September and take a little risk in May and October (though perhaps I should be on standby with the protective fleece just in case!)
Therefore it's a while yet before I should be sowing outdoors, but sowing indoors now means I'll have plants ready for when conditions are right for them in April/May. Autumn sowings will give me some salad over the winter which I can supplement with sprouted seeds/microgreens/pea shoots. It means I can build on the success of my personal salad challenge next winter and buy even less bags of salad than I've done so far :)

Of course the data I'm using only gives the average climate information. What our weather actually does is a completely different thing!

As well as temperature, light is an important growth factor. Its quality has been noticeably different this week: it's felt like the sun is shining on me rather than at me. So I also looked up the daylight hours information for nearby Bath. Yesterday was the first day we've had 10 hours of daylight since the 25th October last year. That's a good enough starting signal for me to commence indoor salad sowing in earnest this weekend :)

I hope this information is helpful for you to find out the potential length of your indoor/protected and outdoor growing seasons for where you live. NB next week is our second Salad Days gathering, so get ready with your salad blog posts to add to next week's Mr Linky.

If you have an interest in the weather - and what gardener doesn't - you might like to check out my ABC of Weather series.

How's the weather (or climate) with you for your salad growing?

Update: Mark at Vertical Veg has found a website which does all the hard work for you re frost dates. However, it's still worth checking to see if the Met Office has a weather station closer to you. The nearest site on the link for me is Bath, which has a slightly different climate to the Met Office data I've used.


  1. very interesting - I'm glad you have looked all that up so I don't have to!

  2. That is just the kind of information I find fascinating but never get round to digging out for myself! thank you.

  3. Lu and Elizabeth - it's all part of the service!

  4. I have presented you with a Versatile Blogging Award. See the details on my blog http://livingin22.blogspot.com

    You can see what you need to do now!


  5. How organized you are! The weather is so screwy around here...very chilled drizzly rain off & on all week (but nary a tornado, thankfully).

  6. Petoskystone - glad to hear you're safe. The tornados have started early this year haven't they?


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