Following my remark in answer to Rose.mary's post, we have done quite well this year with Lettuce. Here are 6 stages. The topmost row is regrowth on the old stumps. Worth remembering?
But there is always the time - as with Carrots at present - when I fail & the Family go out & stock up & then, in a week's time - we are double booking!
And things sown weeks apart will cross over because of growing conditions - as the middle 2 rows show.
PS The lodgers in there are self sown Verbascum. I haven't the energy to take them out!
I have some Sunflowers that did that.. and they are taller than the ones I set!
;D