Everything in the above post is true. My main question is, how much sun gets to the lawn in a day? Is the yard big enough that it isn't shaded all day from the oak trees? If you aren't getting at least 6 to 8 hours a day forget about a lawn. There are certain varieties of St. Augustine that can take some shade but they probably won't thrive. And forget Bahia grass in the shade. Moss and mushrooms are normal in dense shade, don't fight them. Sounds like you need to really think about mass shade planting beds all around the perimeter such as azaleas, camellias, gingers, philodendrons, ground covers, etc. You might be able to have a small center area of lawn. But this could be a spectacular landscape if you work with what you have and not try to fight it. Look around your area at the landscapes similar to yours and see what's working and what isn't. I've found that the more exclusive subdivisions have the best landscaping in the common areas, drive around in some of those. Don't try to fight the conditions, landscaping and turf are very expensive to replace.

If the lawn is not going to be high traffic I just saw a very interesting video on perrenial peanuts as a ground cover. It doesn't produce peanuts.

I am thinking of using it in part of our yard.

Bitter Blue is a good St. Augustine to grow in shade if you must have grass. Nurseries will tell you that all St. Augustine grows in shade, but ignore them. I had Bitter Blue under my oak trees, and it was beautiful with very little care, but once it hit the sun, it either had to be watered or it turned brown almost immediately. People with shade often have two varieties of St. Augustine in their lawns, but unless she is required to have St. Augustine by a homeowner's association, I'd go with ground cover. There are so many wonderful ground covers that do well in shade, I can't name them all, but like I said, we love our gingers and bromeliads in shade. Tropicals like Peace Lily and philodendrons do well in shade too.

Speaking of gingers, if all you want is something hosta-like that is low-maintenance, there is a variegated low-growing ginger that is popular. If you like to cook, you can grow regular ginger, turmeric and cardamom (all members of the ginger family) in shade. Plus, orchids grow easily in shade down here, if she'd like to get into something like that.

As for the mushrooms, the mycelium the spread underground is actually good for your soil, so I don't bother with them. They only pop up once a year or so, and then die quickly. The one you have to be careful of is Fairy Ring, because it is one that will kill your lawn.

One more thing. You can never get rid of all the weeds in your lawn without spending insane amounts of money and putting down insane amounts of chemicals which are harmful to our water table and environment. Don't try. If it's green, mow it. That's your lawn. Nature abhors a vacuum, and nowhere is that more true than in FL. If your lawn dies, weeds will take in and cover that spot seemingly overnight.

Welcome to Florida.Your acorn problem, i just run them over with a mulching lawn mower.some people don't like. having the peaces in the yard.if so use a bag on the mower and compost them or use as mulch.the Florida soil i mean sand takes years to build in to something thats ok.take every opportunity to add organics.that doesn't have to cost much.the best tipe i can give you for the Orlando area is Monterey Mushroom farm you can get cheap or somethings free compost from them it's great stuff and you can get a bag of mushrooms when you are there

I wonder if some pruning of the tree will help reduce a smidgen of the shade and help increase air flow to the area? I know many ppl rarely if ever prune an oak, but sometimes it is helpful to have a tree guy come out to check for any old branches that should be taken out or for over hang above the roof.

I don't think it will give enough light for any real change in amount of grass, but I wonder if it would help lesson the moss?