My new garden has a terrible crabgrass infestation - I have around 20% grass and 80% crabgrass both on my front and back lawn!
I tried a 'moss killer' lawn product in the autumn that turned some patches brown but they soon bounced back. I read that a pre emergent herbicide was the best thing to use so I have bided my time until the spring approaches.
However, now when I come to try and buy a pre emergent herbicide I can't find them anywhere. I am in the UK. I can see lots of American products (surflan, Pendulum etc) that do the job but they are not sold here. Can anyone suggest a suitable product that is available in the UK?
Do you know what surflan or Pendulum are? Do you know the consequences of using them?
Pre-emergent herbicide
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A pre-emergent is a chemical that prevents seed from germinating or prevents seedlings from growing to maturity.
There are many different pre-emergent herbicides. Most are used on lawns to prevent weeds.
Synthetic chemical ingredients include benefin, isoxaben, pendimethalin, atrazine, dithiopyr, trifluralin and others.
The only organic pre-emergent available at this time is corn gluten meal.
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-- Wikipedia Pendimethalin - American Cyanamid Co. Pendimethalin is a preemergent herbicide used to prevent crabgrass from germinating. It inhibits cell division and cell elongation. It must be "watered in" so that the chemical reaches the seeds deep in the soil.
Pendimethalin was included in a biocide ban proposed by the Swedish Chemicals Agency [2] and approved by the European Parliament in January
13, 2009.[3]
-- Wikipedia Dithiopyr- Dow AgroSciences LLC Dithiopyr is a chemical used as an herbicide. It is an ingredient in many products[1] including Dimension.[2]
ECOTOXICITY Based largely or completely on information for the active ingredient, material is highly toxic to aquatic organisms on an acute basis (LC50/EC50 between 0.1 and 1 mg/L in the most sensitive species tested). Based largely or completely on date for major component(s), material is slightly toxic to aquatic organisms on an acute basis (LC50/EC50 between 10 and
100 mg/L in the most sensitive species tested). Dithiopyr is considered toxic to bees.
You may not care, but if I was your neighbor, I'd be in your face.
Thanks for the reply. I am comfortable with using chemicals in a controlled and appropriate manner, as are my neighbours. I would happily try an organic alternative, but even the Corn Gluten Meal seems impossible to obtain from British suppliers.
Has anyone used a pre emergent in the UK and could comment on its effectiveness / suggest a place to buy them?
I'd also be happy enough to try other methods for controlling the crab grass, but short of digging up my entire lawn, what options do I have?
If you've got real crabgrass, not different species:
You can get rid of your crabgrass with a bit of fertilizer, patience and some better mowing techniques -- an old faq of mine:
Easy once you understand the biology of crabgrass, _Digitaria sanguinalis or D. ischaemum_, annual species that germinate in bare soil in cool temperatures, then doesn't grow much until the heat of summer comes. It is intolerant of shade.
1) Fertilize and lime your lawn in spring and early fall, to help thicken it. Best to get a soil analysis from your local master gardeners or extension service, but you can probably wing it a bit with the help of someone who knows the soils in your neighborhood well. If the grass forms a nice, thick mat, it doesn't allow weed seeds to germinate. (Lime helps correct the soil pH to 5.5 to 6.5, which allows the other grass plants to take up nutrients easily.)
2) Obtain a wooden stake and put it in the ground someplace where you can see it easily. If you've got the standard bluegrass/fescue lawn of most of the northern states, make a mark at 3.5" and 4" from soil level. Set your lawnmower blade to 2.75-3". When the grass hits the 3.5" stake mark you should mow. At 4", you *must* mow. No cheating. If you remove more than 1/4 to 1/3 the length of a grass plant in a single mowing, it weakens the plant, possibly opening the soil for weed seed germination. Because the grass stays comparatively long, it also shades the crabgrass seedlings that have germinated and keeps them from developing.
Some times of the year, you'll mow a couple of times a week. Some times (when it's hot), you won't mow for weeks.
The original research on this method of crabgrass control was done back in the 40's or 50's -- the fertilizer used was chicken manure, and the reported success was something like 70% reduction in crabgrass in the first year, and 95% in three years. I tried it myself in a badly abused lawn in a house I moved into... formerly a feedlot, more than 40 species of weeds in the lawn. I used 10-10-10 fertilizer, the cheapest I could find, a little glyphosate (roundup) on thistles and quackgrass (a rhizomatous perennial) and some good quality bluegrass and fescue seed as an overseeding in the fall.
I had virtually NO crabgrass in the lawn the following year, and, in contrast to the neighbors who kept scalping their lawns "to avoid mowing", I was down to 3 species of weeds within 5 years -- without major pain, strain or suffering. The time I spent in the cooler months mowing was certainly no greater than the time and effort the neighbors spent hauling pesticides, spraying, cussing, digging, etc. And I was collecting specimens for the weeds class I was helping with from their lawns, not mine, because I had so few weeds, and so few species of weeds.
The lawn quickly reverted to a weedy mess after I moved out and the new owners went back to scalping the lawn, opening up all sorts of bare soil for weeds to flourish in.
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