K.L.
You could take them to a shop that does upholstry, or a boat cover place and have them sew sturdy straps on the sides or where ever they need to be so you can tie them to the chair frame.
I bought a patio/table set from Kmart at a really good price. The only thing I hate about it is that the chair pads for the back do not have any ties on it so that they don't fly away. How can I fix this? I'm not really a sewing person but I need any advice because I don't want them to blow away! I'd like to be able to do it myself.
You could take them to a shop that does upholstry, or a boat cover place and have them sew sturdy straps on the sides or where ever they need to be so you can tie them to the chair frame.
Try just hand stitching some shoelaces to the cushions where they can't be seen & tie them to the slats ;)
I like the idea of velcro tape that someone mentioned. Also, you could maybe somehow use zip-ties if they will not be seen.
Not sure of the style of the furniture so I dont know if this is plausible, but they do make heavy duty velcro tape. Maybe use this on the underside of the cushions??