Re: Fertilizer -- What & When

What kind to use?  My first concern is to "feed" the soil.  I test it, and
compensate for deficiencies in preparing the beds for planting.  Next, I think
in terms of feeding the plant.  For iris, that means a mixture with at least as
much potash as nitrogen -- usually more.  Save the high-nitrogen fertilizer for
the veggies.

When?  By the life cycle of the plants, not the calendar.  Late summer/early
fall, when the plants break their summer dormancy.  Late winter/early spring,
when they break their winter dormancy.  Periodic foliar feeding through the
spring growth spurt.

Notice how I dodged the question of how much?  My soil test kits came with
excellent instructions -- too much to post here.  Plants, like people, benefit
from a balanced diet.  

Too much nitrogen is said to make iris susceptible to rot.  This seems quite
logical to me, although I haven't been able to prove it in our naturally
nitrogen-poor soil.

Too much phosphorus is said to lead to bloomout.  I have to agree with this,
because I've had much less bloomout even in the TBs since I stopped using
superphosphate in our naturally phosphorus-rich soil.  

Too much potash produces large rhizomes and a massive root system, which does
make digging rather hard on the gardener's back.  

Sharon McAllister (73372.1745@compuserve.com)
Southern New Mexico
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