Sidecaring a crib - What to shove behind mattress?

[BeckC]

I know that when you take the side off of a crib and sidecar it, you need to shove something on the other side of the mattress to close the gap.

My question is, what does one use?

I've heard of craft foam, and I can see where that would work. But I'm going get a natural mattress specifically because I don't want that kind of foam in the mattress, so why would I then stick more in the crib?

What would be a good and also natural alternative?

[Snapdragon]

We use pillows and it works great. but also, the type of crib we got has an extra bar you can attach to firm up the whole crib rather than leaving a whole side empty- I guess they call it a day bed conversion. At any rate, the crib we had before this didn't have that so it was wobbly- so maybe that makes a big difference.
At any rate, we tried the foam and I hated having that foam next to our faces! Pillows work fine for us because the crib being sidecarred is also tied onto the bed so it is secure.
I love the sidecarred crib set up.

[Llyra]

I used tightly rolled cotton bath towels.

[LionessMom]

i used a pool noodle. baby stays near me anyway, but the other things i though of was a body pillow. roll it up tightly the long way and wedge it in there. i also used bungee cords to lash the legs of the crib to the bed. i love the side car set up as well. you could also use a blanket. again roll it up tightly and make sure the ends are tucked down away. it should go the whole length of the matress. towels too.

after almost 4 years of use i need to strengthen the side of the crib that i removed the drop side from. it has gotten all wobbly and no longer feels safe. so that is something to think about too.

[moondiapers]

I went to Michae's and got some really dense cushion foam, covered it in flannel and shoved it in. I also used metal water heater straps to attach the crib to our bedframe.