You don't need a lattice, but if you have one you want to use the gourds would love to grow on it. In a small pot it might only grow 10 or so feet, but it will definitely outgrow your mesh fencing. If you have space you should let at least one vine (either the main vine or one of the side shoots) grow along the ground. Then at the base of each leaf you could mound a little soil to encourage secondary roots. This will help make the plant more vigorous and not as dependent on the pot. If you have a full size birdhouse gourd in that pot you might get 2 or 3 gourds. I had around 11 mini bottle gourds on the plants I grew in the pot. In the future smaller gourds would be better suited for the pot, especially if you want a lot of them.

I did this as a project for my kids one fall and although it was fun it wasn't really fruitful. We got the plain pine houses from Michaels as well. We painted them with acrylics and then sealed them but the problem with these "cheaper" houses is that they are really made to be "decorative" and not to stand up to (at least) the weather where I live. Our little houses lasted on 2 years before they started warping and then literally falling apart at the seams. Real birdhouses are either glued and nailed or glued and screwed for proper...how do you say...standing up to the elements. These decorative birdhouses are just glued together and sometimes a few staples added (mostly the ones with round parts). After 2 years the glue is toast and the things just fall apart. This is ok if you are an avid crafter but in hindsight I won't do it again because in addition to crafstmanship, the house should also have the benefit of proper airflow as well as ability to open and clean it out (neither of which the craft birdhouses have). I just think it's worth the extra 10 or so dollars to get a well constructed house and then do your crafting to embellish it if that's what you like to do. For my kids it was ok for a first project. They were happy with how they looked and we put them up but from now on I will go with the bit more expensive house and do it up right. Barb southern Ontario, CANADA

You want to seal both before AND after you grout. You seal the wood to discourage it from soaking up water like the sponge it is. After gluing and grouting you need to seal the grout with a grout sealer so no water gets into and under your tesserae. Wood outdoors is always iffy (depending on climate of course). Go into mosaicing wood for outdoors with the thought that it probably won't last forever and then you won't be disappointed.

It may be intended to be a butterfly "house". The little I have read about butterfly houses indicates that they don't work very well, though. https://www.pinterest.com/explore/butterfly-house/?lp=true