I notice nobody has responded. There are certainly many many more people out there with greater experience, but I'll tell you what little I have. I'm new to large gardening, but we had windowboxes for a few years at a former house. My husband made them, as well. They were painted on the outside, can't remember if they were painted on the inside. We didn't use liners. The boxes were too small so liners wouldn't fit and it was always a challenge to keep things watered in the Georgia heat. Now we inherited wooden window boxes (commercially made) in our current house up here and they have the standard liner. I will say that the liners do seem to protect the wood from water damage. Without the liners the wet soil holds the water against the wood and accelerates rotting. How visible the liners are once plants get going depends on the color contrast between planter and liner and how many plants drape over. If your husband has some time, maybe it would be possible for him to add some type of trim around the top that would be the right height to hide the liners. Our current boxes are deep eggplant purple and the forest green liner just fades away and is hardly noticeable. If height isn't problem and the windowboxes are higher than the liners but you can see them up close because you're standing above them, then I have no suggestions there! Maybe try to paint the top rim of the liner the same color as the window box?

As for shallowness and dirt, most liners have that water bin underneath to hold water. Between that and the fact that plastic isn't as porous as wood, I wouldn't be surprised if liners actually held moisture better, even thought they leave less room for good potting soil. Last year I put soil retention beads in our windowboxes as two are extremely difficult to water. Hopefully that helped keep them from drying out quickly. They certainly didn't get watered every day!

As for ease, it certainly is easier to cart the liner around when it's time to remove dirt and change plants--that's for sure!

Water rots wood. Liners are a necessity if you want to keep your wood window boxes or other wood containers. What I do is to line my window boxes, bottom and sides, with a double layer of heavy-duty black trash bags. I cut the bags to just about soil level and they are invisible once the plants put on a little growth. Poke holes in the bottom for drainage--and of course, the window boxes should have holes as well. This has worked very well for me. Cheap and they last for years.

Liners do protect the wood, as mentioned above. Also, as you said with your spring bulbs, you can change out plantings. You could even do a third planting of fall-bloomers to extend the season. Obviously, you could do this without liners, but IMO, it would be a bit easier to just get everything planted and then plop the whole liner in.

I think if it was me, I'd go with liners, for protection of the wood if nothing else. Of course, it would take me forever to get my DH to build new ones if needed, so I'd have to make them last as long as possible, lol.

:)
Dee

We had windowboxes years ago. My dad built the first set for me, and years later when they rotted out, we used the same metal support brackets but rebuilt the boxes with new boards.

We always used plastic liners that fit inside the wooden boxes. I used to have red geraniums in the boxes and a couple times I brought the liners with the geraniums in to winter inside.

Our windowboxes were painted inside and out (important to protect the wood) and they had drainage holes drilled in the bottoms, as did the plastic liners. I used to place some broken sections of paint mixing sticks under the liners so that they sat up off the bottom of the windowboxes, allowing excess water to drain out of the liners and out through the drainage holes in the windowboxes.

I don't think that the liners showed at all, but our windowboxes were good sized and also placed quite high off the ground.

I miss my windowboxes and our wooden shutterss, but the expense and logistics of replacing them and adding more when we built our new addition proved too much so we let them go.

Hope to see pictures of your windowboxes this summer. Not having my own anymore I enjoy looking at windowboxes on other people's houses.

Thank you all for the replies! Will definitely continue to plant with the liners and will post some pictures too!