5 days old cuttings in coconut withered and do not grow, thank you very much

without roots it can't maintain enough turgor pressure to hold up the leaves properly A humidity dome will solve this problem. You want transpiration to be minimized until some roots form. This is accomplished with high humidity (or low vpd is probably a better metric). make sure light is 1/3rd to 1/4th of typical vege light over 18hours... or if on a different light schedule from normal, make sure light intensity is further proportionally adjusted from your normal vege light intensity. You won't see above ground growth in 5 days beyond something very, very minimal - if you took pictures from above from same location each day you might see the leaves very slightly expand in surface area, but above ground growth is not necessarily what we want at this point at all... in fact it's more likely a bad sign this early in the process because the plant can only cannibalize itself at thsi point with no roots. At best you might have a root or two that is nowhere near enough to supply proper nutrition to the plant, yet, and more likely just some white nubs that will eventually grow out as roots (unseen below surface). Patience... when you do things right, most will root within 7-14 days, but even then you have to wait longer before it's a properly growing vegetative plant. Some cuttings may not root even in optimal conditions. Always take extras as insurance. the resources needed for them is so low it's pennies of expense to do so.