What are the raised beds made of? Lasagne layering results in considerable shrinkage of the material over the growing season and omits any mineral based soil (ground soil or topsoil), which is necessary for good plant health. Most bagged soil providers will sell a raised bed mix that should work well, provided it has a mineral soil component. If not, just include a bag of topsoil in the mix. The weight of the soil mix, even wet, is usually not an issue with the structure of a properly constructed raised bed frame. But it could be an issue for roof loads :-))

Thanks so much for your response. This is the planter. I have 2:

Raised Planters

They aren't fancy and aren't made of cedar. I was going to put plastic underneath to protect against rot with holes in the bottom for drainage, of course.There is no cross bracing, which worries me.

They are made of fir, which is a very strong wood. And they are intended to be filled with soil so should be able to support that weight easily. They get decent reviews so they must be working out well for others.

Oh, good! So, please forgive my ignorance but what soil(s) would you recommend?

IDK what's available in your area, but as I stated previously, any bagged raised bed soil should work, along with a little garden or topsoil. Maybe a 50-50 mix. Even a potting soil would work well, considering these beds have a bottom and are more like an elevated container rather than a ground level raised bed.

Thank you so much for your help! I really appreciate it!

If growing any sort of veggies in these beds, the OP will want them filled only with planting mix. The box is only 24" deep so will accommodate most veggies. If deeper than required, just don't fill as full :-))

I wasn’t sure how that box measures. It’s 70” long x 24” D x 29” H. I decided that 24” depth didn’t really mean depth, but width. I think the box depth and legs are included in the 29” height. I think the true depth of the box might be around 10-12 inches, because the legs look longer than the box depth. Does that make sense?

As long as you aren't trying to grow long roots like full sized carrots or parsnips.

Yes, it’s a good depth.