[gremlin]

I sow chitted sweetcorn indoors weekly from 1st May. So my last sowing is beginning of June.   Plant out June/ July when they are 6" high.  And I am in the soft South.

I don't know how many weeks later you tough northerners can start sowing. 

[Beetroot Queen]

My sweetcorn had to go in the coldframe they were too big, today they have moved to the unheated greenhouse. Not sure if we will lose them but they aint slowing so far.

[3 allotments]

Sown my sweetcorn last week not through yet,just sown melon courgettes and marrow today

[Headgardener22]

BTW after last year's success, I'm going to chit my sweetcorn. The best solution I found was to chit them for about 3 days by when they would be showing growth then pot the chitted seeds singly into 7 cm pots of compost to grow on. No questions as to whether the seeds would germinate or not, chitted in the warmth at high density then grown on in the polytunnel until big enough to plant out.

To me it was the best way of handling them.

[DD.]

That's what I do with mine!