m0useanswered grow question 10 months ago pre-fertilized medium be is soil or soilless potting mix or won't need any activation or anything.
If its mixed with amendments or slow release fertilizers it will last up to 3 weeks.
If its mixed with salts like readily available nutrients it will last till they get watered out. Putting to many of them in the mix will burn plants though.
I used a soil mix comprised of compost, coir, peat moss perlite and dry amendments. It works out well for me.