"Mike Miller" wrote in message
news:M4s_a.136000$Ho3.16961@sccrnsc03...
The marginals never grow well. The lilies I fertilize, and the WH seem
fine, but the irises, arrowroot, blue pickerel, equisetum (dwarf
horsetail),
all in pots of clay + pebbles, never grow well. Leaves are puny, older
leaves yellow. I remember a thread a year or so ago about nitrate-limited
ponds and adding potassium nitrate, which can't be legally purchased in my
area. If these plants were in the soil, I'd say they're missing nitrogen.

If the marginals are planted in clay, then they need the fertilizer tabs,
since they cannot get the nutrients from the water readily. Take them out
of the clay, and just plant them in pebbles, so that the pond water is
readily available to them and they might do much better. I am having
problems this year with my iris, and a couple of years ago, I couldn't grow
pickerel, and for the last two years, parrots feather is weaker than it was.
I attribute this to the plants consuming some micronutrient from the pond,
until they won't grow anymore. This year the pickerel is doing fine. I
think it might be like the farmer having to rotate crops.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html