Hi Everyone. After posting some pics of these plant trollies in my journal this season, I've had a few requests for a guide to show how I built them. I've grown outdoors now for 3 seasons and utilize pots as large as 25 gallons. Occasionally I find it necessary to relocate my plants during the grow because of unapproving family members coming to visit, contractors needing access to my yard (tree trimmers, pest service, etc), or just for better picture taking angles. During the first two seasons it was really a hassle to lift these heavy plants into a wheelbarrow to get them to a new location. It was definitely a two-person job. This year I decided to make a permanent cart for the plants to grow on that would allow me to move them around without the help of another person. The result was this plant trolley.
Here's the parts list:
 10" wheel with 5/8" bearings.
 5/8" x 36" zinc plated steel rod cut to 28".
 5/8" shaft collar
 2x3" pine stud cut to 27"
 2x3" pine stud cut to 6/5"
 3/4" x 6" pine shelf cut to 20" or  3/4" x 12" shelf cut to 20"
 3/4" x 6" pine shelf cut to 23"
 #8 x 2.5" wood screw
 8' length of rope
I had plenty of scrap wood available, but needed to find appropriate size wheels, axles and other hardware. After a bit of research I finalized on these parts:
View media item 1807447I wanted a large enough wheel to be able to roll across uneven surfaces with ease and something strong enough and durable enough to be able to handle the weight and the weather. The wheels are 10 inches in diameter. The axle is 5/8 inch zinc plated steel rod, and I purchased a matching sized set of shaft collars to secure the wheel to the axle. I bought these all online.
The cost for 4 wheels, 2 axles, and the 8 collars was approx $100. My original plan was to make 3 trollies for 3 plants, and to have 4 wheels per trolley. However, the cost was a bit more than I wanted to spend, so I altered the plan to make 2 trollies with just 2 wheels each, so the cost averaged out to $50 per trolley.
First thing I had to do was to measure my doorway clearance and cut the axle to the appropriate length. My side door to the garage is a standard 32 inches, but actually there's only 29 inches clearance because the door itself takes some of that space. I gave myself another inch fudge-factor, so I cut the axles to 28 inches.
View media item 1807464
I had some scrap lumber and shelving boards lying around so I wanted to use those to keep the cost low.
View media item 1807450
Next I had to figure out how long to make the deck of the trolley. Coincidentally, I settled on 28 inches long.
View media item 1807463
I cut the frame from a 2x3 inch piece of lumber. I already had this, but it happened to be just the right size. I cut two pieces at 28" long and sanded them down a bit just to clean them up (totally optional).
View media item 1807491
These pieces need to support the axle, so I drilled 5/8" holes in each one at 4" from the edge.
View media item 1807492
View media item 1807493
This is how it looks so far:
View media item 1807494
Now for the top deck that will support the pot. I had a couple of old 6" (actually 5.5") shelves and a 12" (actually 11") shelf that I had on hand. One trolley utilized the 12" shelf, the other used  6" shelf pieces. I cut them down to size. The piece (12") that installs closest to the wheels needs to be a bit shorter than the others to accommodate the wheel clearance. I cut that to 20 inches. The others were cut to 23 inches.
View media item 1807495
Now this next step is completely optional. I have a router that I hardly ever have the need to use any more, so I wanted to round off the sharp edges of the boards that I cut. But the functionality of the trolley does not depend on this.
View media item 1807496
View media item 1807497
Also completely optional, I sanded them down to make them look like new.
View media item 1807498
I attached the boards to the frame using the wood screws. I gave about a half inch of overlap at the front and rear, and equally spaced the boards in between. This resulted in about 1/8" of space for water to drain through.
Finally, instead of a 2nd set of wheels at the front, I opted for legs. I added a couple lengths of the 2x3 stud to make it sit level. Ended up being about 6.5" long.
View media item 1807499
View media item 1807500
Finally, I drilled a hole in each of the legs and threaded each end of the rope through.
View media item 1807501
I don't have a picture, but I coated the finished trolley with 3 coats of polyurethane to help it survive the near-daily watering of the plants and the occasion moist air environment.
A final thought about this trolley. It worked really well for my needs this year, but I'm thinking I will either build another with 4 wheels this time, or just retrofit the two existing trollies with another set of wheels. I'm sure it would make transporting even easier.
View media item 1807513