Managing Weeds Organically
Weeds (according to botanists): appear because of seed dispersal, & favorable soil nutrient conditions.
Weeds (according to herbalists): appear because you or your soil needs their medicinal qualities.
Invasive Weeds (according to herbalists): are actually offering a needed medicine for humans or Earth.
Weeds vary widely, so you’ll need to manage each differently.
HARD-to-REMOVE WEEDS: Some are very hardy, deep rooted, spread easily, etc. Examples: Quack grass, bindweed, horseradish. Hard-to-get-rid-of weed management methods include frequent cultivating, starving, hoeing, applying 20% commercial vinegar, etc. Often weed-blocking fabrics do not slow these weeds.
NUISANCE WEEDS: include chickweed, lamb quarters, horsetail, dandelion.
EDIBLE WEEDS: are greens typically far more nutrient-dense that garden vegetable cultivars, e.g. chickweed, lamb quarters, dandelion, nettles.
PLANTS FOR WEED CONTROL: crops that discourage weeds include kale, rape, Mexican marigold, potato, buckwheat, barley. These plants and also trees have an allelopathic effect. That means they exude a repellant substance that inhibits growth of other plants close by. Examples are quack grass and walnut trees. Powdered corn gluten, sold at garden stores, suppresses weeds in lawns on this principle, if spread JUST BEFORE weeds emerge. Corn gluten will kill your crop seedlings too, so your timing is tricky and crucial.
MINERAL NUTRIENTS FOR WEED CONTROL: You can use specific nutrients to deter specific weeds, e.g. apply calcium to suppress dandelions. See Weeds and Why They Grow, re-titled When Weeds Talk by Jay McCaman, 1994.
DROUGHT FOR WEED CONTROL: Minimize weeds by minimizing area that you irrigate. Restrict your watering to the crops only. Weed seed germination is slowed by dry soil.
SMOTHER FOR WEED CONTROL: French intensive methods, cardboard & tarps, and cover crop and green manure strategies work very well to crowd out weeds.
SHADE FOR WEED CONTROL: Crowd out and shade weeds by planting potatoes or a cover crop like buckwheat.
FLAME FOR WEED CONTROL: A quick pass of a propane torch is effective, for example, to kill tiny germinating annuals before carrot seed germinates in a bed. It will not kill roots of grasses, horsetail, or dandelion.
MULCH FOR WEED CONTROL: Apply heavy mulch of organic matter like leaves & grass (Ruth Stout’s method), or a weed block fabric, or newspaper & cardboard. The Verna Pratt Foolproof Method is to lay out 7 layers of newspaper for mulch. Not 8 layers. Not 6 layers. Use the plain black & white sheets, not magazine, comic, or ad pages. These will take 3 years to decompose, adding organic matter to your soil and feeding your soil microbes.
These mulches stop weeds and help retain soil moisture. They keep soil cooler than uncovered soil. They provide slug habitat. They do not stop horsetail or quack grass.
COMPOST YOUR WEEDS? Some weeds like chickweed & dandelions will die in the compost pile. Others like quack grass will survive the compost process and keep growing.
SUMMARY
Minimize soil disruption to avoid exposing buried weed seed. Use a mulch and drip irrigation. Direct your irrigation water to crops, not to paths and edges.
You’ll be removing most of your weeds physically by using a hoe or pulling roots. Find a style of hoe you like so it is comfortable and effective. Pull the roots of quack grass or horsetail, or use smother crops. Don’t rototill or cultivate these two because you will break the root or rhizomes into many sections and they sprout new plants from each segment. Also, do not compost roots of quack grass and horsetail, as they survive even the hot composting process.
Remember:
You will accomplish weed management.
You will never accomplish weed control.
Even with harsh chemical herbicides,
you will never control weeds,
because they will mutate,
develop immunity, and
become super weeds.