Question
Hi Ffloyd, I live in South Wales UK where we have a fair amount of rain. I have a few areas on the lawn that seem to be slightly more wet than other parts and take longer to drain or dry off. Is there any way I can aid the water in it's drainage without damaging the lawn itself. There are also a few bare patches where worms have lifted the soil and there is no grass. Can I repair these places? Finally any tips on feeding to give me a thicker, more lush lawn? Any help would be gratefully received. Many thanks Tim

Answer
Greetings Tim:
I would suggest top dressing. It will take a number of years depending upon the depth of the depressions in your lawn.

First I would aerate the entire lawn area. Aeration removes plugs of soil from the lawn, which loosens areas that may have become compacted by heavy use, and lets air get down to the roots. Whether you use a power machine or a hand tool, keep in mind that an aerator that removes plugs is more effective than one that just pokes holes (which can actually make soil compaction worse).

Top dressing means adding organic material to the surface of the turf. This material is usually a mixture of good-quality soil, sand and a source of humus. The purpose of top dressing is to fill in all the minor low areas that have developed over a period of time, and to build up a soil layer over the years.
The benefits of top dressing are:
Grass growth is denser because the formation of new shoots is stimulated and it promotes the development of runners. Minor depressions are filled in so that a better surface is obtained.
The soil surface is gradually built up and thatch tends to decompose. The water-holding capacity of sandy soil is improved. Drainage in heavy soil is improved, especially if aeration is done prior to top dressing.
There is no best top dressing material for your lawn. Some people use mushroom compost, some people use peat moss, some use composted cow manure, some use their own compost.
A good top dressing  consists of the right mixture of peat, loam and sand. The ingredients should be fairly dry; It should be mixed thoroughly and if it is lumpy it should be passed through a ?inch mesh sieve before applying. I do not suggest the use of garden compost as weed seeds can be a problem.
You can also purchase a quality lawn soil that has been sterilized in place of the loam.
For lawns on heavy soil mix 1 part Peat, 2 parts Loam, & 4 parts Sand
For lawns on loamy soil mix 1 part Peat, 4 parts Loam, & 2 parts Sand
For lawns on sandy soil mix 2 parts Peat, 4 parts Loam, & 1 part Sand
When applying top-dressing, make sure that the crown of the turf is not covered with more than about one and a quarter centimeters of material. If more top-dressing material is applied, the crown can be damaged. The main objective is to promote existing grasses and fill in the depressions over a period of time.
Spread the top dressing mixture at the rate of one and a half kilograms. per square meter, using a shovel to put down small piles over the depressed surface. This top dressing must be worked in with a garden rake so that it is knocked off the grass blades. At no time should the grass be smothered. Using a hose, wash the top dressing off of the grass blades.
It is essential to spread the top dressing so that the deepest part of the depression receive the maximum depth of one and a quarter centimeters and be feathered out from there so that depressions are filled in over time.

Now in regard to the lawn repair areas. Spring or fall are good times to tackle reseeding; the cooler temperatures help the grass grow. First, loosen the top 20 centimeters of soil in the affected area. Then, work seven centimeters of peat moss into the soil. Scatter grass seeds on the soil and water with a fine spray. Keep the area moist until it germinates.

One of the best ways to maintain a good lawn is proper mowing practices.
The two most important facets of mowing are mowing height and frequency. The minimum height for any lawn is 2 inches (5.08 cm). The preferred mowing height for all cool season grasses is 2 1/2 to 3 inches (6.35 to 7.62 cm). Mowing to less than 2 inches (5.08 cm) can result in decreased drought and heat tolerance and higher incidence of Insects, diseases and weeds. Mow the lawn at the same height all year.
Mow the turf often enough so no more than 1/3 of the grass height is removed at any single mowing. If your mowing height is 2 inches (5.08 cm), mow the grass when it is 3 inches (7.62 cm) tall. You may have to mow a bluegrass or fescue lawn every three to four days during the spring when it is actively growing but only once every seven to 10 days when growth is slowed by heat, drought or cold.
If weather or another factor prevents mowing at the proper time, raise the height of the mower temporarily to avoid cutting too much at one time. Cut the grass again a few days later at the normal mowing height.
Let grass clippings fall back onto the lawn, unless they are used for composting or mulching elsewhere in the landscape. Grass clippings decompose quickly and provide a source of recycled nutrients and organic matter for the lawn. Mulching mowers can do this easily. Side-discharge rotary mowers also distribute clippings effectively if the lawn is mowed at the proper frequency. Grass clippings do not contribute to thatch accumulation. If herbicides are applied to the lawn, do not use clippings in the vegetable or flower gardens. Keep them on the lawn.
During the season, regularly check mowing equipment for sharpness and adjustment.
Sharpen rotary mower blades every fourth mowing, especially when mowing fescue or ryegrass lawns. A dull mower blade will shred and fray leaf blades instead of cutting them cleanly. The result is a brown, unattractive lawn.
Check reel-type mowers for proper blade-to-bedknife adjustment before each mowing to avoid shredding and tearing of the grass leaves.

Some web sites you may want to visit are: (Copy and paste to your browser)

Aeration and top dressing:
http://gardening.allinfo-about.com/articles/aeration.html

An article on lawn drainage problems:
http://landscaping.about.com/gi/dynamic/offsite.htm?site=http://www.landsteward....

I hope I have helped. Have a good lawn!
Floyd McMahon

Follow Up information on feeding your lawn:
Fertilization:
Nitrogen is the most important nutrient for promoting good turf color and growth. Do not overstimulate the turf with excess nitrogen, especially during the spring and summer.
Overfertilization can contribute to thatch buildup and increased mowing requirements. Avoid underfertilization of bluegrass and ryegrass. These species can become unhealthy if not fertilized properly. Turf that does not respond to nitrogen fertilizer may be lacking in other nutrients, such as phosphorus or iron. Get the soil tested to determine which nutrient(s) are deficient.
Balanced or complete fertilizers contain various amounts of phosphorus, potassium, iron and sulfur. They are a good safeguard against a potential nutrient deficiency. If you leave clippings on the lawn, these nutrients are recycled from the clippings. If you remove clippings, this type of fertilizer is appropriate.

Choose a fertilizer with the proper ratio of each of the nutrients to correspond to the soil test results. The fertilizer label must state the percentage by weight of nitrogen, phosphorus and potassium in that order. A 20-10-10 fertilizer has the mineral elements in the ratio of two parts of nitrogen, one part of phosphorus and one part of potassium (2-1-1), as does a 10-5-5. The difference is that weight for weight the 10-5-5 contains half as much fertilizer value as the 20-10-10, and twice as much would have to be used for the same results.
Two important factors to consider when fertilizing lawns are how much and when to apply. About 3 pounds of nitrogen per 1,000 square feet per growing season is suggested for most full-sun lawns (Kentucky bluegrass; Kentucky bluegrass mixed with perennial ryegrass and/or fine fescue). Split into 2 or 3 applications, with each single application of nitrogen being about 1 pound per 1,000 sq. ft. About half as much nitrogen is suggested for shade lawns. Percent nitrogen in the bag and size of the lawn (in square feet) are calculation variables as shown below.
To Figure How Much Nitrogen Fertilizer to Apply To Lawns:
a. Divide rate of nitrogen desired by percent nitrogen in bag (first number of 3 on bag, use decimal form)
b. Multiply answer found by square footage of lawn and divide by 1,000
EXAMPLE: 15-5-10 fertilizer, 7,000 sq ft, we will want to apply 1 lb. Nitrogen per 1,000 sq ft
a. 1 lbs. divided by .15 = 6.66, round to 6.7
b. 6.7 multiplied by 7,000 = 46,900; divided by 1,000 = 46.9, or 47 pounds
Therefore, we need about 47 pounds of 15-5-10 fertilizer to cover entire lawn
After calculating how much to apply, when to apply is the other important decision. Early fall (September 1-15) is a key time for fertilizing lawns in the north central area. The schedule below outlines when to apply based on how many applications are to be made annually and desired lawn quality. Use controlled-release nitrogen fertilizers in May and September and a fast-release source in late fall.
For a low quality lawn make one application a year in early September.
For a low to moderate quality lawn make two applications a year. One in early May and one in early September.
For a moderate to high quality lawn make three applications a year. One in early May, one in early September and one in late October or early November.
Have a good lawn.
Floyd McMahon