Changing the type of seed on a shady lawn
I would like to switch my lawn to fine fescue, creeping red. If I cut the current lawn short, put down compost, seed, fertilizer and peat moss, may I expect pretty good results. I am trying to avoid poisoning old lawn. I do not know the seed composition of current lawn. May I do this through November or should I wait until March? I have already bought the seeds and assume they will still be good in March. Thank you.
If you do not want to kill the old lawn, the current grass will compete with the new fine fescue. Whichever one is happier and more suited to the location with grow the best. Both may do well. This is fine. Most lawns in semi-shade are a combination of tall and fine fescues. In fact, that is how many seed mixes are composed (most tall fescue with some fine fescue). If you mow the current grass low, that should give the fine fescue a chance to get sun for warmth.
Grass seed must contact soil. You'll need to scratch up the debris from the mowing so that soil is exposed. Ideally, the soil is roughed up. Spreading a thin layer of compost over the seed is a common tactic. Peat moss is not necessary and can be problematic. Watering is the most crucial component. Read below.
Please read through our publication which gives steps for overseeding:http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG102%20Lawn%20Estab...
We do not recommend seeding after mid-October, because the new seedlings must get established (i.e. have good roots) before harsh winter weather hits. Some years, it's warm like last year and not a problem. Other years a new lawn could be killed. However, since you are in eastern Maryland, you have a longer time period in which to plant. Do so a quickly as possible. The sooner the better.
If you cannot plant this fall, you can plant in spring, but the best time to plant grass is fall. Spring seedlings are often killed by summer heat and drought. (See the publication above.)