Hi Lispeth-

Congratulations on your new house! Here are my thoughts on your questions:

1. How long after I dig them up and then transplant to the temporary bed(s) do I have to wait before digging up again and moving to their permanent beds? Can I do that this fall? I always thought you needed to wait at least a year.

If you can wait a year, I would wait a year. The plants will already be going through transplant trauma with the first dig - let them get settled a bit and regrow roots. Unless you are talking about a very short period of time where the first bed is simply a "holding spot" (1 week or so) before you're moving it over.

2. Can I just make a frame/box from some wood boards (we have loads of scrap wood) and line it with landscape fabric then dump some dirt/compost mixture in and plant in that?

You can. Instead of landscape fabric, you could also just use old newspaper.

3.My old rule of thumb for transplanting was my Grandmother's-as long as the plant is not in bud or bloom you can move it. If it's more than 6" tall, cut it back so that it's energy can go to the roots to get established. Also, it's better to do it on a cloudy/cool day or in the early morning/evening than afternoon. Is this still accepted?

that's how I do it.

Good luck!
Rini

Thanks again for the great advice!

Hi Lispeth,
A new house and a clean garden slate......how great is that! Congratulations.
If you are going to plant in the fall, I would just leave them in the pots making sure there is room for the summers worth of growth and that they get watered. You could either fill around the pots with soil and mulch or make a lasagna bed and sink it in that.
If you thought you could dig in the fall you could still just dig a temorary bed and sink the pots in the bed and mulch....they should overwinter fine.You may want to think about the possibility of lasagna beds anyway seeing you believe the digging is going to be difficult.Good luck and please keep us posted .

Here is a link that might be useful: Our pond and gardens

I break lots of garden rules, and mostly about transplanting. I also created a temporary bed when I moved here. I know when you SHOULD transplant, but I transplant whenever I have time. (sorry, I can't wait for cloudy days after they bloom next year. I have time now, so they get moved now.) I do it in bright sunshine. I do it in bloom. I do it twice in the same year. I have never had any problems as long as I take a good chunk of dirt with them and water thoroughly for weeks after transplanting. In summer I also cut back the foliage quite a bit to avoid them losing too much water. You may sacrifice one season's blooms, but it shouldn't kill the plants. I have had complete success with perennials, the only exception is trees. They do not like to be moved in the heat of summer, and they are quite unhappy if moved more than once in a year.
Most of those rules are to ensure you don't lose this year's flowers, but if you don't mind that, they can be moved anytime the ground isn't frozen.

When I created a transplant bed, since it was only temporary, I jammed them in side by side, way too close for an ordinary bed, in order to save work creating the temporary bed. This required me to water more often, but the plants were fine. Don't leave them more than a year in these crowded conditions.

I would plant them as soon as possible. If you can't, then wait till next spring. In our zone, plants planted in Autumn don't have time to set down good roots before winter. They can heave during those freeze-thaw cycles the next spring, and die.

Yes, you can make a temporary raised bed garden, but put it where it gets shade during the hottest part of the day. Raised gardens dry out and freeze faster, thaw later than plants put into the ground.

Grandma's still right, but you don't have to cut down the leaves unless they are full grown.

Keep the moisture right.