Broad bean help needed.

P.S. Depends a bit on variety - not all are as hardy as the others - see back of packet for details, I sow Aquadulce which are about the hardiest you can get I think

Not familiar with either variety, but I think if it was as hardy as Aquadulce the packet would suggest Autumn planting as well.

We're pretty much out of February without snow and severe cold, so I don't think you are going to have a problem in a draughty greenhouse ...

Last year I started some off in toilet tubes and sowed some direct at the same time(mid march) ... cropping difference was a matter of days

Starting them off in pots is not going to speed them up, per se, its starting them early that does that - or am I missing something?

We are a couple of weeks from mid-March (Hooray!) but starting now in pots would gain two weeks (albeit probably not start cropping much earlier) compared to sowing outside in mid March, and some people will have started them in pots back in January

Ah, sorry, I misunderstood.

I was thinking that I would plant a couple of seeds on the end of the row when I plant mine out to see what the difference between the two is (although I started mine in mid January, so there might be a bit more difference).  But if the difference is "days" I agree that there is no point.

Folk are always saying "Those sown later catch up" but I think it would be more convincing if there was a side-by-side trial. Not sure that I have time to perform a full double-blind trial, but two seeds on the end of the row won't be hard (I'd prefer a couple sown at fortnight intervals, in pots, and then all of them recorded for sow-to-first-harvest duration - that might make the case that sowing from 7-Jan to 21-Jan gives a week or two over a mid-March sowing, but after that its a matter of days - folk who missed the "sweet spot" for indoor sowing would then be well advised to do nothing until the outdoor sowing period

Folk are always saying "Those sown later catch up" but I think it would be more convincing if there was a side-by-side trial.

Yes, I always wondered the same thing, so last year I tried it with tomato plants. Some I started off indoors in February, and some I sowed into a pot in a cold greenhouse in May. The later sown plants did catch up and I'd say overtook the indoor sown plants. The two batches of plants cropped at about the same time but the outdoor sown plants just seemed stronger and healthier plants.