After I was done, I contemplated what to put in the cracks. I was toying with the idea of using sand or topsoil. Well, I procrastinated so long (as I often do) that the problem took care of itself. After 3 or 4 seasons, the cracks filled with dirt and mulch. Because I have a lot of trees, the shade was conducive for moss growth. Viola, problem solved. After a few more seasons (and especially the last 2 wet ones) the moss filled in with a vengeance and actually looks kind of cool.
We've had a couple of late winter snows where the snow laid out he moss for a couple of weeks. When it melted, the moss was almost a neon green color. Wish I had a picture of that.
Last week I took all of the furniture, plants and crap off of the deck to clean it. Because of the trees, it gets really dirty, so I chemical clean and power wash it every year. It's a lot of work but the deck has held up for 16 seasons. The chemical cleaner leaves a bleached look to the wood. I sealed it with Thompson's Water Seal and it darkened it up nicely. So I'm good for another year.
The weather was so nice on Saturday that the Pudge and his buddy were enjoying there lunch up in the Pirate Ship. I don't keep it up as well as the deck and it needs some maintenance - mostly in the rigging. They did fix the cannon by themselves (it fires tennis balls about 25 feet).