What to do with a 3D Printer: Make Garden Tools

Posted by Alex R English on May 20th 2012

The gardening season is here and it's time to get out and work the dirt. Even very traditional home tasks and pastimes like gardening can benefit from a 3D Printer.

I've got a few garden accessories that I've designed for myself to use in the garden this season.

Hanging Garden Trellis Netting

First, I needed a way to hang the trellis for my peas and green beans. There was already a cable stretched over the top of this long bed, so I just needed a way to attach the netting to the cable.  Rather than tie the netting to the cable with twine or wire, I wanted a solution that would lower the net a bit so it would be easier to secure at the bottom. To do this, I designed a small hook several inches long that could be printed quickly several at a time. Here is the finished garden trellis netting hook on Thingiverse. Undoubtedly it has other applications as well, especially since the openSCAD file is parametric and can easily be tuned to different dimensions.

Simple 3D Printed clips for holding garden trellis netting - close-up

Simple 3D Printed clips for holding garden trellis netting - wider view with netting

Seed Spacer

I use a hybrid system to lay out my garden, a combination of square foot gardening and hexagonal plant spacing. Hexagonal spacing provides an aesthetic sense or order in the garden, but it also has many benefits to the plants.  When planted in a tight hexagonal pattern, the leaves of plants will shade the soil, which keeps the soil cooler and slows evaporation. The denser spacing also helps control weeds because the established garden plants will work to crowd weeds out and keep them from coming in. Lastly, tighter spacing means you can get more produce per square foot from your garden (you may get less per plant, but with more plants you get more per square foot). For more information about hexagonal spacing, as well as a holistic approach to organic gardening, see How to Grow More Vegetables by John Jeavons. You can also see this reference on the spacing method as it applies to companion planting.

This kind of spacing isn't too hard to do by hand, but is much faster and easier with a tool to help. This seed spacer was designed to place holes at fixed distances which you can then put the seeds in. Just press the spacer into the soil to make three holes, then lift, rotate, and position the spacer with two of the prongs in two of the previously made holes; repeat.

Here are the spacers (4 inches, 3 inches, 2 inches, and 1.5 inches:

3D Printed seed spacers for sowing a garden

Here, you can see a bed of radishes planted using 2 inch spacing, and a few radishes harvested from that bed. Notice how dense the leaves are and how healthy the plants are (aside from a little insect damage, keep in mind it's organic, so no chemical pest controls). You might also notice that they are inter-planted with clover, which helps fill in the gaps and further shade the soil while also fixing nitrogen to reduce fertilization needs.

Bed of radishes sown using 3D printed seed spacers

Radishes from the garden - sown with 3d printed seed spacer

Here are the designs for the Garden Spacer on Thingiverse, in 4 inch, 3 inch, 2 inch, and 1.5 inch spacings.

For a few examples of what you might plant at different spacing:

  • 4 inch - Peas and pole (runner) beans, turnips, beets, garlic, kohlrabi, onions, parsnips
  • 3 inch - Carrots, bush peas, bunching onions, salsify
  • 2 inch - Radishes and small carrots
  • 1.5 inch - Mostly useful for sowing seed in flats to germinate before transplanting to the garden with broader spacing

Slug Trap

Slugs are a big problem in the Northwest. In the Pacific Northwest, groups of large slugs can take out entire gardens in a night. Where we are in the Inland Northwest, smaller slugs can still deal a lot of damage. After a rain, many small slugs work together to destroy spring plantings like peas and beans. As was mentioned before, we maintain an organic garden, so we don't use any commercial slug bait, but still need to fix the problem. This slug trap helps us kill the slugs in a non-toxic way and add them back into the garden in a helpful manner (the compost pile).

This design is loosely modeled after my go-to slug trap for the last few years. I would take an old tuna can and press it into the soil and fill it with beer. Since the slugs are most active during or right after rain, I found that I had to cover the trap to keep the beer from washing out or getting too diluted. In this old design, I would take the aluminum from the beer can and cut out a sheet with some legs that could be pushed into the soil; this would then be set up like a tent over the tuna can to protect it. While this solution worked, it wasn't the most aesthetic solution, and there were sharp edges to deal with. I'd much rather have a solution that looks nicer, is safer to handle, and which can be made by pressing "print."

This design has a removable lid that allows water to run off the sides, and a reservoir for the beer with gently sloped sides to make the climb a little easier for the slugs. To use it, simply print, fill 1/2 - 2/3 full with beer, put the lid on, and place in the garden where you're most likely to catch slugs. If you have specific plants they've been targeting, try placing the trap near them. You can also try areas closer to where slugs are more likely to hide: logs, rocks, bricks, the edges of raised garden beds, or areas with dense undisturbed foliage like unmowed grass or thick weeds.

3D Printed slug trap

For some reason slugs are attracted to beer. They happily climb right in and drown. You'll want to check your traps daily, and especially after a rain, to see if they need cleaning. To clean, just dump the spent beer and slugs in the compost pile (or trash, or wherever you put your garden waste), rinse out with the garden hose, and refill with beer.

Here is the Garden Slug Trap on Thingiverse.

Community Contributions

There are several other gardening related items already on Thingiverse that were posted by other users. These include a hydroponic pot, a watering spout for a 2L soda bottle, a support clip for wire fencing, a continuous irrigation block for a sub-irrigated planter (could probably also have applications for drip irrigation), and a small garden hand rake. As this gardening season gets going again, hopefully we'll see more submissions like these.

If you post designs for anything with applications in the garden, let us know!