Early sowing gamble

There are six crops that I really value in the garden - they're quite easy to grow, given the right conditions, and prolific croppers. 
Tomatoes
Cucumber
Courgette
Mangetout
DFB
Salad leaves. 

Every year I sow early tomatoes in January BUT why don't I sow the others at the same time? Mangetout and salad leaves should be OK if sown in January and I have done this previously. Cucumbers, Courgettes and DFB are more of a gamble............but, hey, if it doesn't work all I've lost are a few seeds. 

Guess what I'll be doing this weekend?

I sowed an early cucumber 2 weeks ago. It's got its first true leaf already

Thanks for the reassurance, Martin.
I've just dug out my Beth Alpha seeds and the packet says "Sow Feb- May".

All set! Tomorrow I'll sow:-
Cucumber - Beth Alpha
Courgette - Early gem & Sure thing
Mangetout - Bijou
DFB - Orinoco
Salad leaves - Mixed lettuce

I'm sowing lettuce leaves today, just a few out of each packet into a 1/4 seed tray.

Do tell where you are growing these early sowings, indoors, cold gh, warm gh, in propagator, etc.

I'll be starting most of them in a heated propagator in my bedroom! Lettuce and peas won't be heated though and will probably be started in the GH (cold - none of them are heated).

EDIT, they all ended up in the propagator as there was enough room!

I thought you were sowing peas, beans & salad leaves every month anyway? Or is that an old scheme that’s been scrapped? Or did I imagine it?

You may be right but I wouldn't be sowing cucumbers and courgettes every month (although I do remember having 12 little bags each containing the same assortment of seeds that I intended to sow each month to see if I could trick the seasons.). Don't ask what happened to that nutty plan!

All set! Tomorrow I'll sow:-
Cucumber - Beth Alpha
Courgette - Early gem & Sure thing
Mangetout - Bijou
DFB - Orinoco
Salad leaves - Mixed lettuce

The lettuce, Mangetout, DFB and Courgettes have germinated. Just waiting for the cucumbers. Let the fun begin.