If you want to do a low mainteance non CO2 plant tank, do it right.
PO4, KNO3 etc are for CO2 enriched tanks as a rule.

The growth rate is much faster when you add CO2, so you need to add the
nutrients without adding all the NH4 from fish waste that would be
required which will cause algae(NH4= algae).

If you your goal is to improve plant growth/health, you will need to
use CO2 or perhaps something like SeaChem Excel.

You are not going to improve growth by adding something that is non
limiting like PO4/NO3/Traces, the tank is heald back/limited by CO2,
not these other nutrients.

A plant is 40+ % Carbon, and only 1.5% nitrogen, so adding CO2 will
help far more than anything else you might want to add.

Non CO2 method need a good substrate with a fair amount of organic
material. I use Onyx sand, 3-4" and about 1" ground peat and then some
mulm from an established tank.

Some folks use potting soil in place of the peat and sand in place of
the onyx. Soak the soil or peat for a few days first.

Don't do water changes(add for evaporation only), pack the plants in
the tank, add algae eaters also, some floating plants as well(10-20%
surface coverage), 1.5-2w/gal.
Method works quite well.

Regards,
Tom Barr