Be kind to your back. Get your young plants and edible sprouts at a comfortable working height if you can. I hang my nursery with rebar "S" hooks and wire from two points on an overhead pipe attached to a trellis.
Hanging the nursery has several advantages. For one thing, the pipe and wire system I use is much easier to make than are wooden tables. It is more difficult for rats to get to the seeds and young plants to eat them if everything is off the ground. Also, if you ever need the materials for other projects, or want to get it all tucked away in storage, it disassembles easily.
I happened to have an old automobile windshield lying around. I hung it over the sprout trays from two more points on the same overhead pipe using "S" hooks and wire. The glass protects the sprouts from direct rainfall.
Step 1: Materials and Tools
Materials: 1/4 inch rebar, 3/4 inch EMT galvanized iron pipe, 1/8 inch galvanized iron wire. (You need two strong points to hang it all from overhead. I used a piece of iron water pipe attached to a trellis and rebar S hooks to hang everything from the pipe. You have to figure out for yourself how to provide the two points for hanging your nursery. If you can use a pipe like I did, that allows for position adjustments later by sliding the hooks along the length of the pipe. It also allows for the possibility of hanging other things from the same pipe, such as garden equipment.)
Tools: Pliers for cutting and twisting wire. A hack saw for cutting the rebar and iron pipe.
Step 2: Cut and Shape
1. Decide how long and how far apart you want your pipes to be. I recycle Styrofoam grape boxes from the supermarket for the sprout trays and decided 11 inches apart was about right for the pipes. Pipes come in 10 ft. lengths, so I just cut one in half to avoid scraps.
2. To maintain the pipes the right distance apart, I made 1/4 inch rebar units that slide into the ends of the pipes. I bent a zig-zag into each end of the rebar units so that they enter the pipe with a little persuasion from a hammer or block of wood. They will not come out by accident, but they can be easily removed by tapping them out with a hammer.
3. Once you get into hanging things, you will find lots of uses for "S" hooks. I use two strong bolts set about an inch apart in a wood post as a bending jig to make them. By hanging things, you can often times eliminate the need for tables and shelves.
Step 3: Assembly
To put it together, start from the overhead pipe and S hooks using wire that is longer than needed. Hang one pipe horizontally from the two points overhead. Hang the second pipe so that it hangs next to the first one. Then tap in the rebar spacing units at each end.
The spacing unit and the two wires at each end form a triangle. Since the wire legs of the triangle are the same length, the triangle base and the two pipes will hang level.
The tensile strength of 1/8 inch galvanized iron wire is probably good enough to support whatever it is that you plan to hang. If you have any doubts, beef up the design accordingly.
If you start high, you can link more "S" hooks to the ones overhead, like a chain, to lower the nursery. There is no need to change the length of the wires that support the pipes.
Step 4: Glass Cover
I happened to have this glass windshield. Since we get a lot of rain here, I hung it over the nursery unit to provide some protection for the sprout trays. It is hung in a cradle of old telephone wire, the insulation giving the glass some protection from direct contact with the metal wire inside it.
I just rock the glass back out of the way when watering the sprouts.
I like to raise wheat grass for juicing, and sunflower sprouts for salads. I sprout them in pure leaf compost. Put a layer of newspaper in the grape box first to keep from losing compost through the ventilation holes they come with.