We've had pumpkins and tomatoes by the barrow full. Even the odd potato, which ironically did decide to volunteer in a "barrow" this year. Thus my experiment began for growing potatoes. By chance, another potato came up in a bed I topped with our compost, and it has since joined the barrow potato.
I've not had much luck growing things in wheelbarrows, but I'm not one for giving up after the first failure (or two) as I keep learning the more I experiment. Like some pumpkin seedlings which sprouted in another barrow. Rather than throw them all out, I tried transplanting some instead.
Kent pumpkin volunteers
I took a group of three which came up together, and planted them behind a shrub. One has taken off, another is waning (the yellow leaf above) and the second may survive. My strategy to plant them behind a shrub, is finding a "niche" I've seen them develop in the wild as their tendrils search for places to root. They always take root in shady, moist places, which allows their tendrils and leafs to expand out into the sun for photosynthesis.
As you can see, the shrub has shade behind it, which is normal for this time of year. By using a semi mature shrub, I don't have to worry about the pumpkin vine shading it out or strangling it. I have other plants in the garden which are still young, which I have to constantly prune the pumpkin vines away from. I also won't remove the grass or weeds. It all counts towards cover and reducing evaporation. The cool of autumn doesn't evaporate so much, but it can still kill tender seedlings.
I had another single pumpkin I tried transplanting in a more exposed site, but it died within 48 hours. So it helps if you can plant groups of seedlings which volunteer together, as well as finding a semi-shaded site to move them to.
We've been experimenting a lot in the garden, based on what we observe volunteers doing. Next time you see something sprout from the compost, ask yourself - where can I put this in the garden which would mimic optimum growing conditions? It might be that shady side of the house where nothing ever grows. Try planting a pumpkin vine which can travel into the sunlight, and it won't get in the way. Most out-of-the-way places we avoid because of the terrain or reduced sunlight, isn't a problem for plants which can travel by tendril.
Even though I cannot really eat potatoes (avoiding the nightshades) the rest of my family still does. I also want to see if I can tolerate home grown ones. I found that out with dairy. Whenever I eat it, I develop a cough. The exception is when I eat raw milk. I'm hoping its the same with the humble spud!