I was upset this Spring to see a rotting leg on my old potting bench despite good care throughout the years, so it had to go. I briefly considered purchasing a new potting bench and then just realized we could copy the old because I loved it so much and it was a fraction of the cost of a cheaply built bench.
I also use my bench for outdoor entertaining with just some cute flour sack towels under the dishes or for a copper bucket with ice and wine bottles.
If you don't have a power saw, you can easily have your boards cut at the local hardware and haul it all home prepped. I used treated lumber because I don't want to bring my bench inside during winter weather, but it's a personal choice as treated lumber does have some environmental downsides.
The bench only took about an hour and a half to build and had I been smart, I would have stained all of the boards first, but (whatchgonnado), sometimes it takes me a little to catch on!
Here is what you need for construction;
Weatherproof screws 2 inches long
8-1X4 boards 48 inches long (top of bench, back support and top shelf)
5-1X4 boards 45 inches long (bottom shelf boards)
4-2X4 boards 24 inches long (bench supports)
2-2X4 boards 36 inches long (front legs)
2-2X4 boards 60 inches (back legs)
2 1X4 boards 10 inches long (top shelf supports)
(You could also replace these boards with some decorative iron brackets, it would look REALLY great)
Weatherproofing stain or paint of choice
This is mainly a 1 person project, however you may need a helping hand when putting the main frame work together as it becomes cumbersome for 1 person.
Put the sides together first, making sure that the leg bottoms are perfectly level to each other. Attach back support board to topmost back leg and level before screwing in. You want this even with top of leg boards. You may always add an additional 1X4 board here as well, for hooks or a decorative piece of wood (this will be your visible "back").
Measuring accurately, lay out bottom shelf boards and screw in with 2 screws on each side of board. You'll want 1 1/2 inches of space between each board. John and I didn't measure the bottom boards the same as my old bench for this step. On my old bench the boards were 45 inches for the bottom shelf and so they lined up perfectly with the 2X4 support and the most outer edge board of the shelf which is cut to fit between the 2X4 supports. While it looks ok with the 48 inch boards, I preferred the other look. (It was starting to rain and I said to hell with it, just put them on :))
Next start on the top shelf boards, measuring accurately and using 2 screws per side of board with 1 1/2 inch space between edges of boards.
Last we added the top most shelf lining up the board to be even with the entire back of the legs and support board across back. (NOTE; this is where we went a little jenky; Your 10 inch support pieces should be cut with 45 degree angles. As you can see, mine are not. RULE OF THUMB WHEN BUILDING Measure twice, cut once.)
Add your support beams on the inside, lining up with the back legs and put in just 1 screw. Line up your second shelf board and adjust to be level, then add additional screws to attach and secure.
After reading this, it's the most unprofessional builder advice ever, but it should be easy to understand and implement. Small imperfections don't bother me on a DIY project and gives things a bit of character. So don't get too bogged down in the small stuff. You should probably sand your boards ends, I didn't. And as I said before, it would have been much easier to stain the boards first....but I never seem to choose prepared or easy :)
Good luck and Happy Gardening for years to come!!