Introduction: Mailbox Post With Trellis and Garden Box

I received some interest in how I built this after posting it to my Facebook state gardening group page, Even though I wasn't planing on making an instructable and didn't take any before or in progress photos I thought I would create a post that might help someone.

My parents mailbox was keeling over... (in fact I kicked it once to have it fall down to make to the spot ready for the new mailbox) so I decided I would replace it. I originally went to lowes for a prebuilt 4x4 mailbox post kit... but I wasn't willing to spend $40 and something that was rather shoddily put together (the joints/connects were not very good at my store). I decided in-store to use whatever I had around the property(I knew I had some 4x4 posts, 2x8 boards and the livestock panels) to make something a little nicer. I grabbed some 3" deck screws (around $10 for a 1# box) and some plants from the clearance section (1 Clematis $5 and a boatload of $1 Creeping Phlox - I bought 20+ but used around 8 for this mailbox).

I often buy to many boards/posts for projects in the hopes I don't have to go back to the store and I made a design out of the 4x4 pots and 2x8s I already had. While looking for ideas I typed in Trellis Mailbox Post and got alot of pictures of essentially the same design that I ended up with.

I liked this how-to article ( that was sandwiching lattice work between 2x4s. As I didn't have 2x4s, lattice type wood and really didn't want to cut channels in the middle of the 4x4s to slide in my trellis I made a few changes to better suit m materials.

I use livestock feed panels from tractor supply (link in supplies section) for a few things including the fence for my dog, Otter... I also used a panel to make a little fort / watchtower for Otter (See Photos) From a panel I cut two sections out with bolt cutters as close as I could to the edge, with the cut nubs of the panel included the 1st panel was 24.5"Hx16.5"W and the 2nd panel was 36.5"Hx16.5W, these dimensions ultimately determined the length of my posts and where things were cut.

I then used a paper plate and master level drawing skills to put my ideas to 'paper' and write out my dimensions/find my cuts. I was trying to limit the amount of waste generated but I only had 4 4x4x8s to work with for the posts and garden box supports. I used one 8 ft post each for the front/back posts (back post cut at 95.5" / front post cut at 93.5") I used the 3rd 8ft post to cut 2 4x4x40" (top/middle cross braces) and one 4x4x13" (1 of 4 garden box corner braces). The 4th 8ft post was cut into 1 4x4x20 (bottom cross brace) and 3 of 4 garden box corner braces (with about 37" of waste that I will hopefully find somewhere else to use).

I have no idea the terms used for joinery, so hopefully you can understand. I left 24" on the bottom of the back post 95.5" (to go into the ground), cut a 3.5" notch 1.75" deep (to face the road) measured out 36.5" and cut another 3.5" notch 1.75" deep (facing the road) then measured up 24.5" and cut the remaining 3.5" off at 1.75" deep to leave a shelf.

For the Front post (93.5") I left 24" on the bottom of the post (to go into the ground) then cut a cut a 3.5" notch 1.75" deep facing the house, went up 36.5" and cut a 3.5" notch 1.75" deep (one the left side of the post if looking at the mailbox from the road) and had a remaining 18.25"on top.

The bottom cross brace (20") was used without additional cuts

The Middle Cross Brace (40") was used with making a single 3.5" notch (1.75" Deep) on what would end up being the right side (facing the mailbox from the street) 18.25" in. I cut a small slant/angle (I believe 15 degrees) on the side facing the road just because

The Top Cross Brace (40") was used with making a single 3.5" notch (1.75" Deep) on what would end up being the bottom side 18.25" in. I cut a small slant/angle (I believe 15 degrees) on the side facing the road just because

After all joints were cut and chiseled out I dry fit the pieces together to make sure everything fit together (including the trellis pieces)

After verifying fit I connected each joint with exterior wood glue and 3-4 3" screws per joint.

After screwing the posts together the trellis pieces decided they didn't want to fit so nicely anymore. I wedged them in their spots and then used a large hammer/mini sledge and a waste piece of 4x4 block to pound/ force the corners into their position (the center of the 4x4s). I then used pipe / hanger iron cut into short strips (two small holes one big hole) with two 1"+ inch exterior screws going through the small holes and the big hole bending around the wire. (There is a picture of how I used this in my Dog's Watchtower as I did not take a close-up of how it was used in the mailbox) - Keep in mind i used these in the corners for the mailbox rather than a flat surface like in the photo so the hanger iron will be bent more.

I cut the 2x8s into their final cuts (I had 2 2x8x8s cut in half for the long side pieces(to get the extra little bit I did not trim them down to 8' exactly, I just made sure to cut them equally in half; I cut my 1 2x8x10 into fourths - again didn't cut them exactly down to 10' just cut it into 4 equal sections for the side pieces) The box wasn't put together at my place, it was left disassembled so I could work with it later. The 4x4 supports were already cut from the posts (4 4x4x13"

I grabbed a lot of soil I had made for my own plants plants combination of peat, perlite, vemiculite, compost and manure (about a 55gallon trash container worth and it wasn't enough to fill the garden box)

I then transported everything to my parents, I kicked my parents mailbox down and took the large mailbox, the mounting board and the house numbers off and saved them. I re-dug the front hole and back hole with my hole auger, my original plan was to have the bottom cross beam above the regular ground level but below my raised bed garden level, due to the height of my parents property above the road level I had to dig out the area between the posts and bury the 4x4 into the regular ground as the final height had to meet post office standards, I stole the mail box dimensions photo to give an example of height requirements from

After the mailbox post was leveled (for the most part, I left a slight angle towards the road in case any water got in the mailbox, hopefully it will drip out due to the small angle I left. I filled in the dirt to make it ground level again. I then Made the garden box around the post 1 layer at a time, screwing the 2x8s to eachother and then putting in a 4x4 support and adding additional screws; I really don't know how to describe this any better... but I think its pretty self-explanatory. The second layer was then placed directly on top and screwed to the 4x4 posts and the other same layer boards. I placed some newspaper on the ground as a pretty needless weed barrier (as the dept of the soil + mulch is around 14-15" I'm not sure it was needed) and wet it down.

I then added the soil I had brought over and it wasn't enough to fill the box. (I don't have exact amount I brought, but it was enough to mostly fill an regular outdoor metal trashcan) I thought I was doomed to return to lowes just as everyone had just gotten their Covid Stimulus checks but my dad noticed my self-mourning and stated they had some leftover purchased garden soil, needless to say I was happy with that. With what I had brought and a couple bags of garden soil I was able to get it to an acceptable level.

I then added my plants (1 clematis that I helped wrap around the trellis) and some creeping phlox around the perimeter. 1 bag of cypress mulch was enough to cover the top of the soil / around the plants. If I was thinking ahead I probably brought some old firewood/rotting logs over and put them in the bottom to not have to use as much soil and to add long term nutrients but hindsight is 20/20.

I replaced the mailbox support board and mailbox; As I was wiped and done for the day I did not paint the mailbox or add the address numbers back yet. I was originally going to put an hanging/swinging address sign from the top post but I think I'll put one of my solar powered lights/lanterns from it instead.

As I never finish any of my projects 100% in true fashion, unless my parents paint the mailbox /add the address numbers it may take awhile to actually be done done.


Mailbox Post (I made my post dimensions around the size of the

-4x4x95.5 (rear post)

-4x4x93.5 (front post)

-4x4x40 x2 (Top and middle cross beam)

-4x4x20 (Bottom cross beam

-To attach the posts to each other I used 3" exterior deck screws, there were enough screws in the small box to finish the entire project (the screws were the only thing I didn't have on hand for this project)

Trellis (I used am old livestock panel that I already had and cut to size I wanted and made the post dimensions around them)

-Top Panel 24.5H x 16.5W

-Bottom Panel 36.5H x 16.5W

-I attached these two trellis to the posts with cut out hanger iron, one in each corner with two screws per piece ( and two smaller screws (dont waste the 3" screws here)

Raised Bed Garden Box (The only reason I used these dimensions is because I already had these three boards and wasn't planning on buying anything additional, If I were to buy something I would likely use decking boards that are something along the lines of 3/4x6xwhatever or fence boards that are usually 1/2x5.5x6, as they are reasonably prices and you can make whatever size box you want)

-Side Boards 2x8x8' x2 (cut in half so 2x8x4' x4)

-Front/Back Boards 2x8x10' (cut in fourths so 2x8x2.5' x4)

-Corner Braces 4x4x13" x4

-used same box of 1# 3" exterior deck screws that was bought for the post

Plants (These plants I got from the clearance section at lowes), use plants that best suit your growing zone / sun amount)

- 1 Full Sun Clematis $5

-8 Full Sun Creeping Phlox $1 each


-Marking tools (Speed square, Tape Measure, Pencil, whatever)

-Chop Saw (Or something that can cut 4x4 posts and 2x8 boards

-Circular Saw (Used to cut lap joints - or whatever they're called to join the 4x4 posts

-Chisel and Hammer (To finish the lap joints)

-Screwdriver and bits

-Bolt Cutter to cut sections out of livestock panel

-Hole Auger/Post Hole digger---- I have this one (occasionally goes on sale around $55... for me it is so much better than a traditional post hole digger as you don't have to widen the top of the hole to dig deeper because of the handled and it is extendable with threaded iron pipe so you can dig a shallow well with it (the reason I bought it originally, I even have a gas auger that I use less than this) (

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