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Grow/Kill

The Garden will be using "grow/kill" as a prescribed method of weed control in the Meadow Revival Project. 

We will perform a series of "grow/kill" weed eradication treatments throughout the late spring, summer and fall of 2013 and 2014, targeting weeds that germinate in different seasons.

What is Grow/Kill?

Grow/kill treatments can be an effective way to both kill standing weeds and reduce the amount of weed seed stored in the soil.  Tilling, plowing, or turning over the soil in some way, damages plant leaves, while also burying them and depriving them of sunlight.  Tilling also kills plant roots by severing them and exposing them to air. Young plants are easier to kill with this method than older, tougher ones.  By continually destroying new growth and damaging the root system, regular tilling exhausts the weed's food stores until it can no longer re-sprout. 

Typically, only seeds in the top few inches of soil will germinate, but many others lay dormant in deeper layers of the soil. Repeated grow/kill cycles are used to deplete the "seed bank" of dormant weed seeds in the soil. 

Method for Grow/Kill:

  • Start with bare soil: make an effort to remove as much existing seed on plants as possible before the first tilling takes place.
  • Water generously until seeds at the soil surface sprout: this is a usually much higher rate of watering than you would use for a normal landscape. Stimulating new seedlings, regardless of the weather, is the goal.
  • Let soil dry out a bit: tilling wet soil will result in compacted and less workable soil
  • Till to kill seedling weeds and to bring buried new seed to the surface: turning about 4-6 inches of soil is adequate for this purpose.  Tilling should happen before the weeds begin to develop flowers.
  • Repeat

Grow/kill cycles should be used as a weed control treatment only on very weedy, hard to manage sites, as it will effectively kill ALL seeds, even seed of native or desirable plants. Also, give sufficient thought, before the process begins, as to what to plant afterwards, when the cycle is judged successful. Seeding of desired plants or planting of perennials needs to be done at the appropriate season for greatest success.