Allotment bloggers are looking for signs of spring, and for my part I've seen my first snowdrops of the year in the wild. I'm itching to get started. Prompted by other blogs I've already been panicked into buying seed potato far earlier than I intended. At least I got what I wanted. But now I see blogs where seeds are being popped into modules and I'm scurrying off to check whether I should be in full sowing mode yet. Let's be a bit scientific about this.
Here I must point out that I am a fan of outdoor sowing. My plot is several miles accross town and doesn't have an operational greenhouse. At home I do have an unheated mini greenhouse that amounts to a glorified transparent Wendyhouse. There isn't much windowsill space either. And given that I have to transport any homegrown seedlings, wherever possible I sow seeds straight into the soil at the plot.
I've got a god idea of the order of sowing (parsnip, broad bean etc)but how soon can I get started?
The key factors has got to be (a)the seeds' germination requirement and (b)how warm can I rely on it being here in Edinburgh and when. So here goes.
How warm does it have to be before seeds germinate?
There's a cracking table circulating on the internet that results from some experimentation done in the eighties. The only problem is that the information is a bit too concentrated. Here's the chart:
note - click on frame to expand charts
Not clear is it (and there are 3 gaps with no data)
So extracted from the chart here's the information about "% germination" at different teperatures:
and here's the information about days taken to emerge at different temperatures:
The dark green boxes indicate the best germination rates, but the light green boxes indicate enhanced germination rates. The white boxes inicate unfavourable conditions and the blank boxes indicate that it's a waste of time even trying under theses conditions.
When you've got maximun % germination and quickest emergence then you're on a surefire winner. But another factor has to be added that is 'earliness' because its all very well germinating beans at the height of summer but if there is not enough time for them to grow beanspods before the first frost kills them So generally there should be a bias to the left most green shaded boxes.
How warm is it in Edinburgh at this time of year?
Crikey this is bad news. The average Max temperature is 18 whereas my Optimum Germination charts suggest you need at least 20, better still 25 to get the best results. The record high in the last thirty years is less than 30 degrees. Conclusion, in theory I shouldn't be getting a return off my plot at all?
I'll have to return to this after I've had a lie dow. But in the meantime I can see that it's far too early for me to start sowing.
Song of the week: Wonderful World (Don't Know Much)~ Sam Cooke