As a gardener, weeds are a fact of life.   Some weeds are worse than others.  My current battle is with burclover in the front lawn.  It has a velcro spiral seed following the pretty tiny yellow flowers.  At first glance the foliage looks like other clovers, until it sets seeds.  My next door neighbor has a lawn full of it, so I continually find it sprouting in mine in spots.

Some of the weeds found in my yard:

• dandelion Taraxacum officinale
• burclover Medicago polymorpha (prolific throughout our neighborhood and spread by pets and kids.)
• morning glory imopoea (the neighbors have it in epic proportions and let it crawl over the block wall)
• Bermuda grass Cynodon dactylon
• Bermuda buttercup oxalis pes-caprae (I like this one and leave it is some areas)
• Creeping Woodsorrel Oxalis corniculata
• Lawn burweed soliva sessilis (spurweed)
• Sowthistle Sonchus oleraceus
• Creeping Spurge Euphorbia serpens
• Crabgrasses Digitaria spp.
• Nutsedge cyperus spp. – was a problem when I first started gardening here, but through diligent removal of the tubers and the rhizomes, I managed to eliminate it.

UC Davis has a photo gallery for identifying weeds as part of their integrated pest management program:  http://www.ipm.ucdavis.edu/PMG/weeds_intro.html

Organic Weed Control

• My favorite weed killers are my chickens, but they are indiscriminate.  They scratch up any newly sprouted seed in the garden beds they have access to.  If they are enclosed in a fenced pen over the area, there are effective.  They did seem to enjoy eating the few patches of burclover that sprouted in backyard.
• Hand Pulling and digging out tap roots works for things like dandelions.
  
• Boiling Water essentially cooks the existing plants and their roots if it goes deep enough.  I like it because it is cheap, is readily available, and no long term side effects.
• Vinegar sprayed on plants works best on the surface areas, but not always on the root systems.  Use vinegar during daylight hours for best results, the sunnier the day, the better.  Adding a tiny bit of biodegradable dish soap acts an anionic surfactant, thus making the vinegar wetter and stick better. I have read some folks on the internet recommend mixing salt in with the vinegar. I generally would not recommend using salt in the garden. Most yards around here have heavy clay soils, and adding sodium causes decreased fertility and impermeability in clay soil.  Vinegar is less effective on plants with tap roots like dandelions or rhizomes like Bermuda grass.  Vinegar can lower the pH of the soil and if you have alkaline soil that isn’t usually a big problem, but if it is acidic already, you could be causing other issues.
• Corn Gluten or Corn Meal doesn’t kill already growing weeds or plants, but it works as a pre-emergent organic herbicide on the seeds.  I buy a big bag of corn meal and spread it out in the fall where I don’t want annual weeds to come up.  I usually use this on the lawn.  The bagged commercial versions of corn gluten sold specifically for the garden aren’t cheap.  Also, as it breaks down, it helps to amend the soil.
• Newspaper– A thick layer, sprayed with water, and then covered with mulch is very effective at smothering weeds. As it decomposes it actually helps to improve the soil underneath.  This is my favorite long term solution for large areas and I typically do it to areas where I am starting a new bed.  In addition, it can be planted in immediately by cutting a hole, big enought to accommodate a root ball, through the paper and planting in the gap.
• The only organic solution I have found for getting rid of Bermuda grass, is digging deep and slowly sifting out every piece of the rhizomes. Unfortunately, it is a necessary lawn grass at our home because it is less thirsty than fescue type grasses, but because it is so invasive I have a hard time appreciating its good qualities.  As soon as I turn my back, it creeps back over the edging and into the flower beds.  If there really are levels in Hell like in Dante’s Inferno, Bermuda grass will be on the level where evil gardeners are sent.

My feelings on Chemical Herbicides

I typically don’t recommend the use of them and I prefer to use organic methods, but I understand there are situations that chemical herbicides are necessary.  Glyphosate based broad spectrum herbicides (like Roundup) are very effective in killing plants, but they are toxic to birds and fish.   This type of herbicide stays tied up in the soil, especially soils high in organic matter, for as long as 6 months.  Rain and irrigation do not leach it from the soil.  It has to be broken down by microbes over time.  Based on these factors, I choose not to use Roundup.

If someone told me their only effective option is to use a chemical herbicide on an area, I would suggest they follow the directions very carefully, wear protective clothing and mask, and after applying it make sure to keep pets and kids off the area twice as long as instructions on the bag recommends, just to be safe.  Any shoes that walk on the area should also be left outside, rather than come in the house and track the chemicals on to the floors and carpets.