"Do they really prefer slightly acidic or alkaline soil."

Yes, they really prefer acidic or alkaline soils. Or Neutral soils.

Dandelions will grow just about everywhere. Trying to gauge soil conditions by the weeds that are growing is inexact, to say the least. The concept is that certain weeds indicate the conditions of the soil, and these weeds are called indicator weeds. I've seen indicator weeds growing in conditions that are very different from what they're supposed to indicate.

I 'mostly' agree with bpgreen about your weeds. Though dandelions much prefer an alkaline pH, they will grow just about anywhere. ;-) Rather than using indicator weeds to try to determine the pH of your soil, why not call your local extension office and ask them where the most reasonable place would be for a simple pH test. Just the pH.

Anyway, I tend to think that a weedy lawn is more a symptom of maintenance issues. Improper mowing, watering, and fertilization practices can set your lawn up for a major weed takeover. Does that make sense?

My neighbor is a perfect example. She scalps her grass when she mows, with dull blades no less. She waters three or four times a week for about 5 minutes.

I water 5 days a week at least for 5 minutes. If I don't they turn pale green or yellow. You might ask me I have fertilized. Yes I have twice this year with Whitney farms lawn fertilizer even then I have clover now and during spring there was moss in some areas.
I stopped mulching my grass a year ago, someone told me to since my lawn was thining out.

I am seriously considering adding lime. Do I have anything to loose.:)

-lg

If you have a proliferation of one or
two types or weeds then you can draw
some conclusions about your soil but
a dandelion or plantain here or there
really doesn't say much.

Watering "5 days a week at least for 5 minutes" isn't doing much good for the grass. I suspect that your lawn is thirsty because the roots are very short.

The goal for a lawn is to get the water down at least 8 to 10 inches. To know for certain just where the moisture is in your lawn, dig a test hole, or simply probe with a trowel. How deep does the moisture go?

Try watering once a week for 25 minutes. Then test as above.

If the water runs off before the end of the 25 minutes, try several on-off cycles -- perhaps on for 10 minutes, off for 10 or more, then repeat as needed the same day.

What do you mean by "I stopped mulching my grass a year ago, someone told me to since my lawn was thining out." Do you mean that you stopped leaving the clippings on the lawn?

If so, grass-cycling (keeping the clippings on the lawn) is a wise practice as it substitutes for about 1/4 of the fertilizer a lawn needs during the year. Either mow often enough that the clippings are short (for me, that's about every 4 days) or use a mulching-mower.

Or is it that you add compost to the lawn area? If so, know that a number of people in our region do add compost and are successful.

As for lime, in your location, it's suggested that you lime the lawn every 2nd or 3rd year. The stuff is quite inexpensive.

If yours is a clay-based soil, use the regular agricultural lawn for gardens/grass. Don't bother with dolomite lime unless your soil is sandy.

When it comes to moss -- well, know that moss is a common thing here in the NW. Some folks enjoy it, others consider it as gross. But its presence indicates that you have good quality air, also that the soil where it is growing is moist and/or compacted and/or shaded.

Jean001, thanks for the advice. I definitely intend to improve
my watering habits and apply compost and compost tea also.

In the long run, if I resort back to mulch mower and periodic compost tea application, will these two methods, suffice my fertilizer needs. It is difficult for me to
add compost every year and coffee ground do not seem to have
enough punch.

Regarding mowing did you mean if mulching mower is not used then mow very often otherwise
use the mulching mower.
I mow regularly every 2 weeks, should I be using
mulching mower. Could this not lead to thatch formations?

Regarding lime, I read that areas that get more than 30 inches of annual rain, liming is essential. Especially over use of fertilizers would tend to make the soil acidic over time.

-lg

Grasscycling or using a mulching mower has been proven to reduce thatch rather than encourage it. I'd consider mowing more often - weekly - but at a higher setting, leaving at least 2 1/2 - 3 inches intact. FWIW, I use a mulching mower and have not fertilized my lawn in years - it simply isn't necessary IME.

PNW soils are naturally slightly acidic as is the rainfall. If you want a pristine lawn, liming may be advised, but I haven't found that to be a requirement also. Moss formation is typically the motivation behind frequent liming in the PNW but lime really doesn't adequately address the issue. Mosses grow in NW lawns primarily as a result of shaded conditions and soil compaction. Selecting something other than turf grasses for shady areas and aerating annually then topdressing with a thin layer of compost will help. I consider aerating one of the most important things you can do to encourage a healthy lawn. That and the correct watering practices Jean outlined.

lazygardener,

First, you need to know that compost tea is not a fertilizer. (I don't know how/where the notion that it's fertilizer occurred.)

Part of the problem may be that you're mowing every 2 weeks. The general guideline is to remove a max of 1/3 the blade length. The mowing frequency for my lawn (just a few miles north of where you live) is once every 4 to 5 days. (My mower is a basic manual sort -- you push it or nothing happens!)

As has been explained, clippings don't create thatch.

When it comes to rainfall, our area gets about 40 inches in a normal year.

Dandelions much prefer to grow in a slightly acidic soil, about the same soil pH as most of our turfgrass does, 6.2 to 6.8. They also prefer to grow in sandy soils that are moist, which often seems to be a contradiction, but they will grow anywhere there is ample soil moisture and sunlight, your lawn, and not much competion from any other plant, most grasses. You will seldom find dandelions in tall meadow grasses, or forests, but they are very often found in pastures.
While many weeds can give a somewhat close indication of soil conditions the single best way to find out about your soil is with a good, reliable soil test, which while it may appear expensive could save you money in the long run by keeping you from buying and applying material that is not needed, or could create more problems if applied in excess quantities.

The number one job of biology is survival. So to see weeds thrive in varying environments is no surprise.

Two weeds are part of a system so you need to look at the whole picture. Is it shady, lawn or planter, sandy soil/clay soil, low or high traffic? There is science but field research is long and arduous enjoy the processes.

Lastly they are indicators not precise instruments.

While I have no idea why we are revisiting a 14 year old thread, I would just add that dandelions are not an indicator plant at all!! They will grow anywhere other than boggy ground, tolerating a soil pH of 4.3 to 8.3. They are also found in nearly every country in the northern hemisphere, from subtropical climates to the arctic circle.

Dandelions have redeeming qualities though they have long tap roots that help break up compacted soil and pull up nutrients from very deep in the soil so planting the plants you want to grow around them benefits those plants that then get a mass quantity of nutrients that they wouldn't have been able to pull up themselves. The dandelions make great spinach substitutes they are a nutrient powerhouse, you can make jelly from the flowers, or eat them on salads

"pull up nutrients from very deep in the soil so planting the plants you want to grow around them benefits those plants that then get a mass quantity of nutrients that they wouldn't have been able to pull up themselves."

While this may seem true, it is nonetheless incorrect. The bulk of soil nutrients are contained in the top layer of the soil profile. That's why the feeder roots of trees and shrubs are located right below the soil surface. The deeper you go, the less nutrients available. And while tap rooted plants - like dandelions - can help to loosen compacted soil, they have NO ability to pull up nutrients from deep in the soil profile. They are not even that very deeply tap rooted......12 inches is nothing compared by the roots produced by alfalfa or daikon radishes, which can produce roots that extend anywhere from 6 to 20 feet deep.

A lot of wild plants in yard indicates grass is in soil at or below 6.3 Ph. These weeds are taking in the nutrients faster than grass at that Ph, because it's so far below the optimum nutrient uptake Ph value of Grass, which is 6.8 to 7.0.

Grass will do fine between 6.0 and 7.0 BUT if you don't use pre-emergent herbicides to keep the weeds out, these weeds will steal nutrients from the soil, malnourishing the grass. It's like saying, grass will do fine between 6.0 and 6.3 if its the only plant there.

With that low of a Ph, you'll see the cool season loving Clover and violets, the warm loving Dandelions, the heat loving Crabgrass, Plantain, Creeping Charlie, Nimblewill, Sedge

Do a soil Ph test 5 inches down to determine soil Ph. Consult back of bag of lime to look at its chart to see how much lime to use. The chart will tell you how much to use to obtain a 6.5 Ph based on your current Ph.

Once obtain 6.5 Ph, use 12 pounds of lime per 1000 sq foot every year for maintaining Ph. No less often than 36 pounds every 36 months.

If you're dead set against doing a Ph test, use 14 pounds of lime per 1000 sq foot every year until you see the type of grass health you're looking for, then switch to 12 lbs per 1000 sq foot.

Since moss will die out from malnutrition past a 6.5 Ph, you can keep adding lime to your yard every year at the rate of 14 lbs per 1000 sq foot until the moss dies out., then go to 12 lbs per 1000 sq foot per year.

Keep at least a 6.5 Ph so the grass is healthy enough to become and remain established.

Consider also, grass height. At 4 inches, lawn grass goes into down and out growth mode, focusing more on roots and side stems called a stolon, than on vertical growth (blade growth). At 4 inches and at least a 6.5 Ph, you have your self maintaining lawn, you won't have to water as often, or mow as often. 4 inch has the best weed suppression, the best insect suppression. Grass won't go dormant in the heat of the summer at 4 inches because it is only prone to dormancy when the heat comes if its focusing on blade growth, and grass is susceptible to dormancy to the extent that its focusing on blade growth (the lower the grass, the more prone it is). The grass blades will be thicker together and will be a darker green all year.

At 3.5 inches or lower, one must use a pre emergent herbicide such as Haltz or Killz to keep weeds out, and overseed at least every three years to keep the grass lush and thick, and use nitrogen rich fertilizer such as turf builder to keep it dark green.

Your maintenance is to use lime to first obtain then maintain at least a 6.5 Ph, using no less often than every three years, ideally every year. If the grass is 4 inches, use pre-emergent herbicides in trouble spots like fence posts, flower beds, side of buildings. Below 4 inches use pre-emergent in entire lawn, use Turfbuilder, and overseed at least every 3 years for thickness.