Mike wrote:
"Emerald" wrote in message
oups.com...

What plants like potassium?



Banana plants

Seriously, Wolf, do you have any sources for Potassium, Nitrogen or
phosphorus besides chemicals at the store?

Firstly, my list of what's good for what was in error: fast typing, I
guess. I apologise. Here's the real scoop:

Nitrogen: stems and leaves
Phosphorus: roots
Potassium: flowers and fruits.

The sequence of numbers of fertiliser labels is N-P-K (nitrogen,
phosphorus, potassium). Or "shoots, roots and fruits."

Secondly, um, er, all fertilisers are chemicals. In fact, you and me are
made of chemicals. :-)

Compost is a low-level source of pretty well everything (on the order of
0.5-0.5-0.5). But the main value of compost is that it loosens the soil
and increases water retention, as well as introducing all kinds of
beneficial critters into that sandy patch you're trying to change into a
rose garden. :-) Compost is essential for a good garden. But bewa
compost sold in bags at your friendly local box store may be sterilised,
which is both good (doesn't introduce strange critters into your garden)
and bad (doesn't introduce any critters into your garden.) (BTW, peat
moss is nutrionally empty and acidifies the soil. Use it only to improve
water retention, and add limestone or dolomite if necessary.)

Composted manure is somewhat better as a fertiliser source (in the range
of 1-1-1 to about 3-3-3, depending on source). Straight manure tends to
be high in nitrogen, so use it carefully. Fish emulsion is high in
nitrogen and phosphorus. (I've used smelts as fertiliser here - one
year, I grew marigolds in pure gravel laced with dead smelts.)

Downside of composts is that some seeds survive the composting process,
and you will have to do a lot more weeding.

Potassium and phosphorous sources in artificial fertilisers are usually
ground up minerals: crushed rocks, actually. (Potash is mined in
Saskatchewan - most of the potash in North American fertilisers comes
from there. It's dissolved, pumped up as a brine, which is evaporated to
retrieve the mineral for shipment.) Guano (bird s**t) is still a
significant source of phosphorus worldwide, as are bones from our
hamburger animals, and fish, in addition to minerals. Nitrogen sources
in artificial fertilisers are usually ammonia compounds made from
petroleum, but animal byproducts are also used (eg, blood in
blood-and-bone mneal.) Rain (esp. during a thunderstorm) is a
surprisingly significant source of nitrogen.

The major drawback of artificial fertilisers, especially the cheap ones,
is that they tend to be poor in micronutrients. NB that fertilisers
made for agricultural use may have micronutrients (mostly metals) added
- farmers know what they need. MiracleGro is one of many fertilisers
with micronutrients added, which is why it works so well. But you pay
extra for its brand name. Housebrands are just as good. Read the
ingredients.

The notion that "organic sources" are better for plants is a myth.
Plants are mineral eaters. The only advantage (minor, IMO) of organic
sources is that they may contain enzymes, which are sometimes
beneficial, and they may contain those micronutrients. The downside of
organic sources is heavy-metal concentration, especially in animal sources.

But the nitrogen, phosphorus and potassium have to be broken down into
pure mineral salts before the plant can use them. Some plants can do
this to a limited extent themselves, but most rely on bacteria and/or
the effects of water and oxygen to do the decomposition, hence the need
for a healthy soil. If you feed a plant a diet of pure minerals
dissolved in water, it will be very, very happy. Just ask the growers of
hydroponic tomatoes. :-)

HTH