Potatoes and tomatoes- some experiments, and some questions

In lock down this year I have been able to really get on with my vegetable garden in a meaningful way. It's been super fun, and has taught me a lot. Mostly, what doesn't work in my area due to pigeons and rabbits, but it is still useful stuff!

Anyway, my big new experiment this year is tomatoes - I've never really grown them in quantity before. Usually a couple of plants in a pot somewhere, that ended up with me due to someone elses surplus seedlings. I've never germinated my own before.  The seedling were a success, despite starting fairly late, and I now have about 30 plants out in the garden. I'm hoping they get enough warm weather to ripen. I have another dozen in the greenhouse as well.

I was doing my reading about spur pruning, and discovered that you could root the spurs in a glass of water for later planting out.
Experiment 1 - will spurs, taken at the end of June (28/06/2020) and rooted in water indoors, have enough time to bear fruit? I think this would be a really useful thing to determine for future years.

Shortly after my spur pruning I was walking around the garden and realised that potatoes are both closely related, and also have some spurs - albeit no where near as many as tomatoes! It set me thinking, could I root them in the same way? And if they root would it give me a way to do a late season planting of potatoes to get an extra crop going into Autumn?

Question 1- has anyone tried rooting potato spurs?

Question 2 - If you have, what were your results like? Did you get a crop?
I wonder if this might be a way to extend both the growing season, and the number of plants from a given set of seed potatoes.

Experiment 2 - I took half a dozen potato spurs, and put them in water in the same conditions as the tomatoes. If they root successfully I will plant them out in a new bed in a few weeks time.

Potato stems will root very easily as long as you take them before flowering/tuber induction.  You will get a single stemmed plant that will have a smaller yield than a multi-stemmed plant started from a tuber.

How did your experiments do Michael? I'm thinking the end of June is probably a bit late in the UK to start a tomato plant....

The tomatoes grew to large plants and set some flowers, but didn't have time to form proper fruit. I got hit hard by blight towards the end of the summer which stopped everything dead.

The potatoes were a "sort-of" - thing. Of the 6 or so spurs I set in water, 5 rotted, one grew some short roots, but then never got going.

Thanks Michael for the update.
It sounds like that rooting the tomato spurs would still be worth doing if possible at the start of the season - particularly if you only had a few plants.

Hi Michael,
Your premise is solid, but those of us in the northern climates do not have a long enough season to take advantage of it.

I know of people in the southern US who grow tomatoes in the spring and harvest tomatoes. When it gets too hot, they take cuttings and root them in doors. By the time the tomatoes are ready to be transplanted it is cool enough for the plants outdoors again. They get a to harvest a second batch of tomatoes. There is just not enough time in the north, without serious greenhouses.