Compost is an amendment. You have to evaluate your native soil and then amend it with compost if you think it is subpar. Topsoil is just dirt amended with compost and allowed to age, and the aging is important.If you are growing in sand or clay you might want to bring in some topsoil to mix with your compost and the native soil. If you’re starting with good loamy Soil you probably don’t need it. One of the things with compost is that it takes a while to break down. So It is usually tilled in in the fall after your harvest so it has all winter to break down. One of the things I have experienced, because I have to hammer my holes in Rocky, hard, dirt with poor drainage, is that the roots will be happy just staying in the hole and not migrating into the surrounding medium. The plants will grow tall but in the fall when you get a windy rain storm you can come out to find your Plants have topple over or have started to topple over because the roots don’t have a solid foundation to anchor in. So returning at least 50% of the dirt you’ve dug out of the hole and throwing in your amendments and stirring it all up helps too mitigate So returning at least 50% of the dirt you’ve dug out of the hole and throwing in your amendments and stirring it all up helps too mitigate that problem but it can still happen. But if you have good draining soft substrate that the roots grow into then you’re probably golden. But if you are looking up at the Colas in September I would stake them just to be safe. It’s no fun Being out in the middle of the night, in a Gale, With rain pounding, trying to keep your girls from going over or falling apart. Done that too.