Question
I have a lot of cedar trees around my lawn, and the 'leaves' get on the grass. The lawn is also moderately shaded. There is also a moss problem. I have heard that applying lime to the soil will help grass grow by reducing the acid pH due to the cedar tree 'leaves'. Is this true? I have heard regular 'barn lime' will help if spead on the lawn. But how to apply and how much?
Thank you for your response.
Tom  

Answer
Good afternoon Tom:

In regard to the shade problem:
Successfully growing turf in shady sites can be difficult. Reduced light and air movement, competition for water and minerals, and stressed turf that is intolerant of traffic or disease are common problems in shade. Most cool season turfgrasses perform best when grown in full sun. Shade tolerance, however, is greatest in the fine-leaf fescues and least in Kentucky bluegrass. Tall fescue and perennial ryegrasses have intermediate shade tolerance.
Shade-tolerant turfgrasses reportedly tolerate reduced light situations better than other turf species. They still require 2 to 4 hours of direct sunlight per day to perform acceptably. In areas where there is not adequate light duration or intensity to support acceptable turf growth, a ground cover may be a better choice.
Plant ground covers that tolerate shade, such as Japanese spurge, English ivy, hosta, periwinkle, or purpleleaf wintercreeper. Another option is to simply cover the shady area with a landscape mulch such as wood or bark chips.
Turfgrasses growing in shade require somewhat different management than those growing in full sun. Avoid overfertilizing with nitrogen, and maintain adequate phosphorus and potassium. In addition, avoid overwatering. Overfertilizing and overwatering in shady areas can lead to disease problems. Reduce foot traffic in shaded areas. Mow at the highest recommended height for the turfgrass species. Encourage light and air movement into shaded areas by pruning low-growing limbs and removing shrubs.

In regard to the moss problem:
Moss in the lawn is a common problem. Moss signals that grass is weak and has thinned for some reason, allowing the moss to take over. There are many causes, including excessive shade, compacted soils, poorly drained soils, low soil fertility, high or low soil pH, and poor air circulation. Poor lawn care practices are another source of moss problems. Lack of care, including irregular mowing and little or no fertilizer applications are common problems leading to poor turf growth.
Adding limestone is a common "remedy" mentioned for moss control. It is not suggested unless a soil test has shown the pH needs to be raised. Many soils have already have high pH values; adding limestone will make this pH go even higher, adding to the lawn's problem. Your local Cooperative Extension can help you obtain a soil test. (See below)
Ferrous ammonium sulfate or ferric sulfate (iron sulfate) can be used to control moss to some extent. The moss will temporarily burn away, but usually returns fairly quickly. Raking out moss and reseeding is another option. Make sure the proper grass for the conditions are being used.
Changing the conditions to favor lawn grasses and discourage moss is a good way to manage the problem. Too much shade for acceptable grass growth is a common cause for moss invasion. Pruning trees and shrubs to improve air circulation and light penetration is a good way to start.
Take a look at the soil conditions. Reduce soil compaction by core aerifying. This may also help correct drainage problems. Serious drainage problems may require more extensive work to correct.
Evaluate your lawn care procedures, especially fertilizing. Lawns need adequate fertilization, in particular nitrogen. Lawns in shady areas need less nitrogen than in full sun. About 1 to 2 pounds of actual nitrogen per 1,000 square feet per season is all that is needed in shade, compared to 2 to 4 pounds in full sun.
Excessively short mowing may be a source of the moss problem; a range of 2 ?to 3 inches is ideal for most lawn grasses. Mow regularly to avoid removing more than one-third of the leaf blade at each mowing. Also avoid excessive watering, as this may also contribute to moss problems. Water deeply and as infrequently as possible, based on lawn needs.
How to take a soil test:
Testing the soil is the best way to determine the nutrients your soil may be lacking and the amounts required to provide for your new lawn. A soil test will also indicated the soil pH (acidity or alkalinity) that may need to be adjusted. Soil testing information and services are available through private testing companies or your County Extension office. When you send your soil sample in to be tested, request that the testing service provide you with fertilizer and other amendment recommendations for your lawn.
To take a soil sample for testing use a spade, trowel or bulb planter to remove a plug of soil six inches deep. Obtain similar cores from other random locations in the area of your lawn. Mix the soil thoroughly in a clean pail. Remove about a half pint of the well mixed soil and let it dry at room temperature. Remove debris such as leaves, vegetation, sticks and large stones. Fill the soil test container to the amount required. Either mail or deliver to the soil test facility.   

General notes:
All conifers such as cedars will add acidity to the surrounding area. This does not mean that you should lime the area until you are sure that it is required and in what amount. Grass will not grow under conifers because of the dense shade not so much because of the acid conditions.
If the soil test indicates the use of lime, I would use a good agricultural lime not "Barn Lime" used for white washing.   
Have a good lawn!
Floyd McMahon