Good practice is not to add anything to individual planting holes. Spread amendments over the entire surface of the bed.

Really

Why?

Humus is what is left after compost is fully decomposed.....eg. completely finished. You really do not need to worry about it - it just happens naturally but in its own time.

Thanks floraluk2

I'll check it out

I see the point of what he is saying but i think, as he pointed out, the girdling will be more apt to happen in a tree or shrub

ill be planting annuals, for the most part

their root systems do not, i think, will venture far out of my very large planting hole thanks for the info, though. i will definitely use the info when im doing a larger scale project

thanks!

The current wisdom is not to amend any planting holes----including when planting annuals. https://artofstonegardening.com/no-more-amendments-to-planting-holes 

" Another reason compost doesn’t help the planting hole is because the new plant doesn’t have any motivation to venture out from the rich, amended soil it was stuck in. It is gaining all its nutrients from the enhanced soil so its roots don’t want to grow and settle into the surrounding natural soil. Why would they? "

“Roots react much in the same way as they do in containers: they circle the edge of the interface and grow back into that more hospitable environment of the planting hole.”

So if the roots are happy in the amended soil than why not let them be?

" So if the roots are happy in the amended soil than why not let them be? "

Because the driving force in a plant's vitality and ability to thrive is its root system so it makes sense that this is not limited or encumbered in any manner, even for less extensively rooted perennials and annuals and most especially when it comes down to any woody plants and their far extending root systems.

Also amending the soil for individual planting holes causes soil interface issues and water tends not to percolate through the soil profile evenly but instead creates pockets of excessively damp conditions that can create root rots.

Ok

2 things

ive always mixed granular fertilizer in the planting hole. that shouldnt effect the root mobilty, should it?

is it advisable to spread the compost and other ammendments around the drip line?

at planting time?

It is never recommended to fertilize new or newly planted plants. They are already heavily fertilized at the nursery and the planting or transplanting process stresses them and the ferts are not metabolized properly. Ferts should also not come into direct contact with plant roots - it can burn them.

Any amendments you want to apply should be used as a mulch or topdressing only, never added to the planting hole.

Im planting quite a few seedlings that have only been fertilized in their trays

should i top dress them with fertilizer

Wait to see how they do before applying anything. Most plants are able to get all they need from existing soil nutrients. Fertilizing is never a requirement.

Thank you!

Resist your urge to reach for stuff. I saw the zinnias you grew, and they were way overloved, stunted by something you applied. As gardengal said, you're better off putting the plants in the ground and watching how they like things. When you fertilize your plants in trays, which unlike ground plants have no access to nutrients, you should use a weakened solution and when you put the plants out, do not fertilize them unless you see them struggling in a few weeks. If you want to top dress them, use compost. I use compost, attract pooping worms, and rarely fertilize anything.