Why Weeds Win -  A Brief Tribute

Weeds in charge. Photo by I.  Stephens

When you see a garden out of control and its vegetables are hidden among the weeds, it's easy to suspect a "lazy gardener." But, as experienced gardeners know,  the odds are really in favor of the weeds to win. New gardeners generally just don't realize  how much the deck is stacked against  them.  

As soon as any  gardener starts spading and clearing a plot for vegetables, that gardener actually is creating  ideal conditions for many plants (in this case, weeds) whose seeds have just been patiently waiting - maybe for a few days, a month, a year, ten years or even decades to get started.  Plants have evolved their reproductive patterns to accommodate  the vagaries of climate, soil and the flora and fauna in their environments. Our backyard environmental disturbances in the soil just  fit nicely into their coping strategies. Although gardeners may occasionally curse about  weeds, the resourcefulness of these plants to cope with whatever Mother Nature or homo sapiens throws at them deserves a lot of respect. --  And, knowing what I'm up against also does provide  me with some solace... occasionally.

FWIW:  Most of our common garden weeds were introduced by the early colonists, i.e. the Puritans et al, whose saved garden seeds and animal fodder also contained the seeds of our familiar weeds. 

Most plants rely on   the shotgun approach when it comes to seed production - the more seeds produced, the better chance that at least 1 seed will survive and be able to grow. The following two factoids  clearly  delineate  what gardeners are really up against and why weeds will out live us:

Common purselane - 2,000,000 seeds per plant.    Seeds viable for 20 - 25 years

Eastern black nightshade - 800,000+ seeds per plant.  Seeds viable for 40+ years

I could cite more, but it would get repetitive and be more depressing. Plants use various strategies to get their seeds dispersed such as  wind, water, edible fruit  and even exploding pods. Many plants also employ other propagation methods:

• Stolons, commonly called runners, - these are above ground stems that can set roots, e.g. crabgrass (yuck) or strawberries (yum); 

• Rhizomes - underground stems that can sprout above ground stems, e.g. quack grass, wild morning glory,  and bindweed;

• Spores - a complicated cycle used by some non-flowering plants such as  ferns. [Conifers, however, (i.e.  evergreens) are also non-flowering, but do develop seeds in cones.]                                       

The seeds naturally  found in  soil are referred to as the "weed seed bank." Although some plants also use stolons or rhizomes to reproduce, they chiefly rely on seeds; and it's the seeds that we are up against.  The Iowa State U. diagram of the "weed seed bank" below shows what the weed cycle looks like.  

Iowa State University

What  the diagram does not convey is the cycle's real complexity.  Some seeds need to be buried first under the soil and be dormant for varying periods of time. They will not sprout until they are uncovered.  Others need to be exposed to cool temperatures or to specific moisture levels before sprouting.  Still others, need to stay on the surface and experience warm temperatures to become dormant for next year. 

Seeds in the soil bank get moved around by different means such worms, insects, burrowing animals and  human cultivation. Birds  and  other animals eating a fruit and/or an entire plant will distribute seeds away from the mother plants after the seeds pass through their digestive tracks.  

Strategy for Weed Control Without Herbicides

Unfortunately, the strategies for controlling weeds boil down to two that gardeners naturally do:

• Plant removal before  seed cycles develop, and      

• Sprout suppression.      

Reducing the  weed seed count in your garden plot is achievable, but entails a multi-year effort.  Landscaping cloth (sometimes now called "weed cloth") is effective in suppressing weeds, but may complicate your efforts to use compost.  Using just mulch will do the job, but can take a number of years to become an effective  barrier assuming your mulch is weed seed free.  Probably the best approach is to use a landscape cloth or black plastic either  at the end of a season or in early spring (10 - 12 weeks before planting time) to suffocate most of the weeds.  When you are ready to plant, remove the cloth or plastic, add your compost and/or mulch; and,  if you happen to remain  motivated, you can reinstall the cloth [not the plastic] to the garden for the growing season.

And remember:

"The richest soil, if cultivated, produces the rankest weeds." - Plutrach