Any photos?

My thoughts are: Have you been feeding them?  Are all the leaves yellow and have they changed at the same time or just the ones at the base? When were they last potted on? Was potting on into a new batch of compost?

If they are standard varieties might be worth getting some from a garden centre as a back up.

If it is snapped off below the seed leaves it's done for. Above seed leaves but below the true leaves, likely done for, but some hope.  Above sets of true leaves, there is a much better shot at the plant recovering.

John is working very hard to get the balance right, so please be patient with him.  It’s not an easy job 

We've spent hours on it so far. Every time I remove from one section they are popping up in another. Google did a big update/change and so many sites have been hit badly. Even large ones such as the Daily Mail, who will have their own dedicated staff to handle it, are unable to sort out the new AI placements and swamping.

For now I've removed all ads from the main chat sections landing page and removed another chunk of sections within topics and posts. Now to see what the new AI ad monsters decide I need to fix tomorrow!

This is my first year growing cucumbers after my husband bought some plug plants. One of them came with the top half snapped off. May be a dumb question but will it still grow or have I lost the growing point?

Planted out a courgette plant I've had in the cold frame. Planted some peas out that were in modules in the cold frame too. Found a packet of pumpkin seeds so sowed them in pots and placed in the empty space that the peas and courgette left. Went over the grass areas with the push mower