permaculture

["Lawrence F. London, Jr." <lflj@bellsouth.net>]

I have had to develop a strategy for dealing with redroot pigweed over
the years. Facing serious colonization in fields and gardens have hand 
pulled hundreds of large plants. The number of seeds eliminated that way 
was uncountable and dramatically reduced annual reappearance.

From:
"A Manual of Weeds"
by Ada E. Georgia
The Rural Manuals
L.H. Bailey, Editor
Spiny Amaranth
amaranthus spinosus
[redroot pigweed]
"...like all its family, seed is possessed of long vitality in the soil"
Means of control:
Prevent seed production. ...cut or hand pull plants before flower
spikes develop...
...it is late blooming plants that usually seed the soil...
...cultivate/plow/harrow land after crop harvest and sow a winter crop
[cover crop]

My own thoughts on control and gradual elimination of pigweed from
gardens and fields:

Mow or scythe areas before the pigweed goes to seed or cultivate/harrow 
instead making sure it is tilled under.

1) pull or cut pigweed plants or mow or till soil to eliminate them,
well before they go to seed
2) cultivate ground to shallow depth (disk harrow or spring tooth
cultivator or even rototiller)
3) allow existing pigweed seeds to germinate and sprout
4) cultivate ground again, cut under pigweed or mow field
5) lime & fertilize plot as needed
6) plant cover crops
turnip greens or winter rye or both; pigweed will grow taller and will
be easy to spot and pull by hand
alternative crop: rye grain and clover (use less fertilizer)
7) repeat process in Spring, plant collards or more turnip greens or
turnips as cover/cash crop
turnip greens are medium height and grow very thick, shading the
ground, collards do same
kale might not work as well
8) Spring-Summer: follow greens crop with squash and cucumbers,
cantelope or watermelon

Winter rye will probably work just as well and is an exceptional soil
builder. Old timer farmers in my neighborhood,
specifically Mr. Charlie Thompson,  a legend in his own time :-),
frequently commented on this.

Turnip greens are an excellent cover crop to use for eliminating
weeds, they are good at outcompeting but you will need to
leave them in the ground to flower and further shade the ground; weeds
that otherwise would have germinated and sprouted won't
under these conditions. Be sure to cut them down before they set seed.
Use of this scheme will result in nearly complete elimination
of pigweed in your fields. The occasional plant that appears can be
pulled by hand. Feed the greens to livestock, especially poultry.