presuming they aren't food plants.. i don't see why paint inside the box would make any difference ... but i really don't see any paint that is going to take the dampness and stay intact for all that long ... frankly.. i wouldn't bother painting the interior ... just too damp a situation ...

since you are saving a lot of money building them yourself.. consider using cedar or redwood or treated lumber .... it might cost twice as much.. but it might last 3 times as long ... and personally .. i would let them naturally gray out... and avoid having to paint them every year .... successful plantings.. will hide the box anyway ... but my house is grayish anyway ...

also .. consider your design ... and make them large enough .. for pots ... or maybe gallon milk jugs with the top cut off ... and drainage holes.. to avoid planting in the box itself ... a little transitory water overflow from a pot/container .. will not rot wood as fast as .. constant year around damp soil ... make sure there is plenty of drainage out the bottom of a wood box ....

also consider materials other than wood ... that might fit the project .... just brainstorming here.. but what about no care decking material... mine came in 8 inch wide 5/4 boards.. but were very heavy .... think outside the box..

good luck

ken

link to google images of square plastic pots....

design the planter to hold the pots.. and keep the soil off the wood ...

use chicken wire at the bottom.. so all water drips right on through ...

ken

Here is a link that might be useful: link

I use newspaper to line the bottom of my plastic containers that I put in the window boxes. The plastic containers are lifted off the bottom so they don't rest there, keeping it dryer.

Susan, I've been thinking of building my own planters also, despite the fact that I can't hit a nail with a hammer, lol. But I want large boxes (4x3 feet and 8x3 feet and about 3 to 4 feet deep with a shelf inside so the actual depth is not so deep - they'll just look deep on the outside) and I can't afford to buy them.

Mine will definitely be painted on the outside to match the house, (which they will be against) and I was toying with the idea of lining them with plastic. But, I was also going to go Ken's route and build them to hold pots. I would just place the pots inside the planter boxes. I was doing this more so I could do seasonal displays than for the water-damage aspect, but that's an added bonus.

Didn't think of the chicke wire bottoms. That's a good idea.

Good luck to you. I hope you have better carpentry skills than I do, lol!

:)
Dee

Everyone,

Thank you for the tips. Hi Dee, well I took 3 years of carpentry in High School back in the 70's I am from a very forward thinking state, MA! LOL

I liked Ken's tip of the pots, so I found 30" long plastic window boxes withsnap off bottoms, that is what I am using. I will build the boxes paint them and put the window boxes inside.

Thankyou so much for the brainstorming.

Susan in NC