RE: CULT: Preparing for an iris garden

I'm not sure how useful my "bed" preparation technique will be for
anybody else, but this is what I do.

My soil is deep, loamy gravel valley alluvium, up to 90% coarse
fragments bigger than1/2 inch in some places, mosty clay loam in
others.  Most is more gravel than soil, and the gravelly areas are
nearly impossible to dig except when moist.  Sets up in dry weather like
aggregate concrete, especially if there's been any livestock or other
traffic on it.

First, I kill any existing vegetation with Roundup.  Sometimes several
applications over several months.

I grow most of my iris in rows, first laid out with the tractor and
subsoiler.

Subsoiler is a massive, flat metal bar pulled edgewise thru the soil
that busts up the rock/gravel/soil mass down to about two feet deep.  In
the process of busting things loose, the surface of the soil is raised,
sometimes as much as 8 inches.   Because of the rocks, once this slot is
opened in the soil, if I don't drive over it or walk on it, soil and
rocks usually stay fairly loose in and around the original opening for
many years, even when totally saturated with 1 or 2 inches of rain/day
several days in a row.  The raised area also persists for several years.

Depending on various factors (energy, enthusiasm, functionality of
tractor, number of plants I need space for), I then either go back over
the row with a 'set of plows'/one row cultivator with the tractor or dig
by hand.

The cultivator I use has a set of 6 little plowpoints at the end of
curved spring steel arms, 3 on either side of the center line busted up
by the subsoiler.

They aren't designed to go as deep as the subsoiler, and in my rocky
mess, only can loosen the soil to about 6 or 8 inches, unless it's
really wet (by which point I lose traction).  By design, they tend to
'throw' dirt towards the middle, towards the line plowed by the
subsoiler.

If all goes well, this results in a slightly raised bed of loose soil
(the important thing), as much as 8 inches above the middles, and 12
inches or more wide, with a channel of loose soil in the row middle down
as deep as 2 ft.

If I dig by hand, I use a heavy duty spade fork and heap soil towards
the middle to get a similar result.

If I'm planting somewhere other than in the rows, I loosen soil as deep
with the spade fork as I can manage & now and then empty out a big hole,
fill the bottom with fresh horse manure, then re-fill with soil.  The
manure provides a moisture reservoir, & gravel all around ensures good
drainage.

When re-using areas previously lined out with the tractor subsoiler, I
dig by hand, mostly just loosening soil on either side of the center
line, moving some of it towards the center to compensate for settling,
digging, and weeding.

I then add a generous amount of crushed dolomitic limestone, following
Barry Blyth's catalog suggestion of looking like a light snowfall, plus
N-P-K mineral fertilizer.  I've been using high phosphorus tobacco
fertilizer - can't remember the exact formulation 5-15-10? -  the last
couple of years and like the results better than 6-12-12 or 10-10-10,
but it may be weather related benefits more than fertilizer diffs.

If the spot is new to iris, I bury a handful of alfalfa pellets in the
planting hole for adult plants, if I remember.  Soil tests showed boron
deficiency in my gravelly loam, and I have arbitrarily decided alfalfa
pellets are an easy safe way to add a miniscule amount of boron.

Otherwise, I just dig a hole and plant.  Water immediately if it isn't
raining, mulch mature rhizomes with lawn clippings and cover with a
little tent of leafy tree twigs in hot dry weather, add water if/when it
doesn't rain for several weeks.

Char, I dont' know how useful all this is for a typical gardener, but
maybe it will help.  Not very useful for 'blueprinting' but maybe
helpful for concepts.

--
Linda Mann east Tennessee USA zone 7/8
East Tennessee Iris Society <http://www.korrnet.org/etis>
American Iris Society web site <http://www.irises.org>
talk archives: <http://www.hort.net/lists/iris-talk/>
photos archives: <http://www.hort.net/lists/iris-photos/>
online R&I <http://www.irisregister.com>

---------------------------------------------------------------------
To sign-off this list, send email to majordomo@hort.net with the
message text UNSUBSCRIBE IRIS
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index