In a9e253c1b1958e0212c28af7749e6e4a@TeraNews Shiva wrote:
You know, this echos the current trend in human nutrition science that
holds that "whole" foods have a greater overall benefit, although we
have only begun to understand what substances in them bring the
benefit. Roses fed only whole fertilizers may also benefit from the
lack of salt(s) found in synthetic fertilizers.

At the end of the day, feeding roses ANYTHING involves adding chemicals
to the soil they are growing in.

With artificial fertilisers you are feeding roses what we gather are the
main ingredients (NPK and trace elements).

Organics have the advantage of added extras, some no doubt yet to be
discovered by research. They can also have beneficial hormones and
microbacteria. Their downside is that they can miss some basic
necessities for plant growth and imbalance soil just as easily as
artificial fertilisers. Three examples:

(a) Blood 'n' bone (aka bone meal) is great for slow release nitrogen
and calcium. Hopeless for phosphorus, potassium, sulphur, magnesium and
other things roses need.

(b) Chicken manure has plenty of nitrogen and phosphorus. It's also
acidic enough to whack soil out of balance.

(c) Seaweed, by contrast, will never imbalance soil and it has trace
levels of just about every element including gold and selenium. It also
has a lot of plant hormones that promote root growth. But its nitrogen,
phosphorus and potassium components are also only at trace level, not
enough to sustain a rose bush.

I've therefore come to the conclusion that the best diet for roses is a
combination of artificial and organic. Relying on either exclusively
creates gaps, either in the main elements or in trace elements and
hormones.