"With the exception of the aged horse manure, none of those items requires any composting before application. I might have used the tumbler just to mix the stuff up and fully incorporate all the diverse ingredients, but I wouldn't have added any water and I would have applied it immediately after mixing. " This is what I was thinking too. This is a collection of fertilizers and already composte materials for the most part. Don't pile it up, your problem is you don't have enough air and it's loaded with nitrogen esp. from the bat guano. The reducing conditions that result are decomposing the gypsum (calcium sulfate) into hydrogen sulfide which smells horrible. OMG you've created a monster! Spread it out to dry and put it on the garden and mix lightly into the surface, is my advice. No heat necessary. Wow!

You are just coming out of a long winter and so grass does tend to look awful at the start of the year. I doubt this has to do with kind of grass that's been laid. It's not the gardiners fault. You have an issue with animals - I can't understand why squirrels or cats would need to dig there. I might suspect a raccoon because they are normally after beetle grubs which come to the surface around thsi time of the year. They tend to rip open grass to reach to this areas. Squirrels normally dig to get to their hidden nuts or to get at tulip bulbs. Cats dig because they need to do their business there. Crows just stick in their beaks to grab the worms. So my thoughts are -- raccoons are doing this. If you pull up a section of your grass and see grubs, that's what's causing the grass to have patches and for holes dug by raccoons. You will definitely see lines along where the tiles of sod meet. I suspect you put down the grass just before fall and before the grass managed to meld into each other. Heres a simple remedy, --detaching - that is scratching the grass to remove the dead grass. Deal with the grubs - in Ontario we can no longer use insecticides. Perhaps in Montreal it's different. Barring insecticides, the organic way is using nematodes (a microscopic worm which attacks grubs and are available at garden centres). Next add good top soil, (if you have a large area to cover, it's cheaper to get them by the truckload. - Next spread it thinly all over the yard like you are icing a cake. I like using the back of my rake to do this job. Next spread new grass seeds. I do this every 2 weeks to ensure the gaps I've missed are covered. New grass will germinate in about 2 weeks and in no time you willhave a great looking yard again. Hope it works.

Thanks everyone, we are very appreciative of what the builder did for us as this could have been a major disaster. We are currently looking for a new house and excited to see what we can find. We think the builder might of had other request for houses in the neighborhood and with the lots full couldn't sell them one. Maybe they knew they could sell the house with the demand. I will be happy for them if they do sell the house and happy for the family that gets it as long as it meets their needs, also happy that we didn't end up with it.

Not too late at all. Turn on the water to sprout as many weed seeds as you can. Water it 10 minutes, 2x per day for a week. Then spray everything with Round Up. Continue watering like that for another week and spray anything new that pops up with RU again. Rake up the dead stuff with a rake or power rake. Level with minimal amount of sand if needed to fill low spots. Scatter seed and roll it down with a rented water fillable roller. Then restart the watering for your new seed. You should get very few if any new weeds after the two RU apps. If you use a tri mix of seed with rye, fescue, and Kentucky bluegrass, you will have to know the germination characteristics of the three grasses. Rye will get 80% germination in about a week. Fescue takes 2 weeks. KBG takes 3 weeks. If you stop watering daily after only one week, you will have a full rye grass lawn and not have the other two.