What plants are you referring to?

Assuming you mean tomato plants then a single plant is all that can even tolerate only 5 gallons. And even then it is heavily stressed. So what and where have you been reading differently?

Now whether you prune that plant to a single stem or not is your choice. It sure isn't required in any way.

A single un-pruned plant with multiple stems - which is normal for most tomato plants - is not the same thing as putting multiple plants in the same container regardless of the container size.

Have you been pruning your plants in 15 gallon containers to single stems too? If so, why?

Dave

I know the cherrys for sure I will be trying - BC, SG and Lucky Tiger.

For the pinks, blacks, - Brandy, Prundens, Cherokee, etc - I'm thinking I might try a pot and doubling up and see the cause/effects, Just need to make sure it's just supported right. Last year, I had some heavy winds topple 2 containers that broke the stem around the 2-3 feet mark.

I plant out tomato seedlings in multiples. Usually in pairs. As far as I've ever been able to figure, the behavior of those two plants in that space is pretty much what a single plant in that space would do. That is, productivity wise, they act like two stems on one plant. I guess it might be different for containers, though.

My motivation for doing this is simple. If something happens to one plant, the other is there to fill the space. If something happens to a singly-planted plant, you've got a big hole in your garden.

Single stem for 5 gal sounds about right. For 15 gal it's kind of a waste, you could put two plants with single stem there or more stems, etc.

Double/triples in 5G pots? They must have been talking about micro/mini toms. 2-3 full sized toms, even dwarfs, isn't going to work well IMO. If nothing else, putting big plants into a container so small makes them topheavy and prone to toppling.

I use a 20G party tub for a single indet tom. And I plant my toms singly in the garden beds too. I've never had a problem with losing any of them.

But they don't get to be full sized. You get two half-sized plants, which look a lot like one plant with two stems, and they add up to one whole plant.

So kind of like stunting two plants instead of having one unstunted plant? That is an interesting approach.