A temporary ledger is a straight board fastened level to the wall so a course of panel siding can rest on it while you fasten off. It is the most common way crews hold a full sheet, and on new construction at ground level it works fine. The cost shows up everywhere else: you level and fasten the board, hang the course, back the fasteners out, patch what they left in the sheathing or the weather barrier, and rebuild the whole thing one course up on every wall. On a re-side the board has to bear on finished material. Over a block or foundation base there may be nothing to fasten it to at all.
What a temporary ledger is
Snap a level line where the bottom edge of the course needs to sit. Fasten a straight board just under it, usually a scrap 2x4 run flat, using screws rather than nails so it comes back off. Rest the sheet on the board, get your edge spacing, fasten the panel off, then pull the board.
It is a good instinct. It turns a two-person balancing act into a two-person placing job, and the material is already on the truck. Panel manufacturers recommend it themselves, either as a board or as a couple of fasteners left standing proud on the line.
Where a ledger is genuinely the right call
Be honest about this before reaching for anything else. A temporary ledger is hard to beat when you are working on new construction at ground level, the sheathing below the line is going to be covered by the next course anyway, nothing below the line is finished, and you only have a wall or two to run.
In that situation the board is free, it is fast, and the holes it leaves end up buried. There is no argument for buying anything.
Where it starts costing you
1. The rebuild, on every course, on every wall
The ledger is not one setup. It is a setup per course. Level it, fasten it, hang the course, unfasten it, move it up, level it again. On a tall wall with several courses, that is the same twenty minutes repeated until the wall is closed in, and it happens while the rest of the crew waits on the line.
2. The holes, once anything below the line is finished
On new work the fastener holes disappear behind the next course. On a re-side they do not. The board has to bear on siding somebody already paid for, and every screw is a hole in a finished face that has to be filled and touched up. If the weather barrier is already detailed and taped, each fastener is a penetration through the one layer whose job is to keep water out, and the barrier manufacturer's guidance governs how that gets treated.
3. Nothing to fasten to
This is the one that stops crews cold. If the first course laps over a block or concrete foundation, there is often no nailable base where the ledger needs to sit. You are drilling masonry for a board you are going to throw away, or you are giving up and holding the sheet.
4. The nails-left-proud version has its own failure
The quicker variant is to drive a couple of fasteners on the line and rest the sheet on those. It is faster to set and faster to pull, and it fails in two specific ways that crews report consistently: set the sheet down hard or too far out on the fastener and it bends under the weight, and the head marks the back edge of the panel where it lands. On a pre-finished or engineered panel that mark is not always hidden.
What changes with a row of hooks
A row of support hooks does the same job with a different trade. Each hook takes one fastener instead of a board spanning several studs. The panel's bottom edge rests down in the foot rather than balancing on a flat edge. When the course is fastened off, you tap up on the exposed bottom of each hook and it releases from the fastener, so there is no backing anything out and the fastener itself ends up behind the finished panel rather than in front of it. Moving up a course is a tap and a reset on the next line, not a rebuild.
It is not free and a scrap board is. That is the actual trade, and it is worth making honestly: you are buying back the setup and teardown on every course, and you are avoiding holes in anything that is already finished. If you are siding one shed on bare sheathing, the board wins. If you are running walls for a living, or re-siding over finished material, the arithmetic goes the other way.
See the full comparison in EZpanl vs cleats vs panel clamps, or the wider set of options in how to hold a siding panel while you fasten it.
What does not change
None of this changes the crew. Panel siding is a minimum two-person job because a full sheet has to be lifted and positioned, and no support method changes that. A ledger, a clamp or a row of hooks all do the same narrow thing: they hold the sheet once it is up, so the hands that were holding it can fasten it instead. See why panel siding is a two-person job.
Your panel manufacturer sets the fastening schedule, the clearances and the gaps, and their current printed instructions govern over anything here. See how to read a nailing schedule and clearance and gap basics.