The keys are good ventilation and good drainage.
Ventilation: Is there skirting around it or is it open?
Drainage: What's the slope underneath the deck. Is it uniformly down and away from the house?

Thanks for the reply! no skirting. Mostly uniformly down and away from house -- except where dogs have dug to cool off next to house foundation.

A friend came by today to help remove materials (ie, old metal fence posts) that had accumulated under the deck, so now I have better access for maintenance.

A few days ago, I did spray underside of deck and ground, as well as surrounding yard with insect repellent and already see signs of improvement.

This has been a more than usual rainy year. The ground is a little muddy.

I am having the ground under the deck back filled because the slope is not good enough and rabbits have called it their home. They will fill in the dirt, put down landscape fabric, then put large egg rock under the deck. I have it in one flower bed and they will do the other bed. That way when someone is there they can see the gravel continue from the bed to under the deck. I can't take care of the weeds anymore and this will be a big help.

Double post.

This post was edited by EmmaR on Thu, Jul 10, 14 at 18:20

Good idea Emma. Perhaps that would help me with my dogs too.