Small-Scale Nursery Tools
Design small tools for seedling trays and test them on real seedlings, not on paper. The ideas come from volunteer shifts at Barron Park Nursery and Florist in Palo Alto.
Module sheet 4 of 5
- You make
- One seedling tool, drawn, built, and used on a full tray
- You measure
- How many seeds come up and how many seedlings survive a move, with the tool and without it
- Bring
- A seed tray, potting mix, quick seeds such as radish or lettuce, and something to build with
- Toward a sale
- Seedlings and small tools are cheap to make, and a tool that saves a grower time is easy to explain.
Tools for things that are still alive
Module 3 was about getting a tool to work. Here it also has to be gentle: a seedling's roots tear if you pinch them, and a seed planted too deep may never come up.
- Planting depth. Why every seed has a right depth, and how a tool can hit it every time.
- Roots. Lifting a seedling by its root ball instead of its stem.
- Soil in small spaces. Filling and packing cells evenly without pressing them hard.
- Keeping track. Labels and spacing that survive watering and moving trays around.
What to build your tool from
From around the house
| Material | Becomes |
|---|---|
| Chopsticks | Dibbler handles |
| Popsicle sticks | Transplant lifters |
| Bottle caps | Micro-scoop heads |
| Cardboard | Spacing guides |
| Straws | Mini stakes |
| Wire | Clip-on markers |
| Rubber bands | Adjustable spacers |
From the printer
- Dibbler tips with depth marks
- Scoop heads shaped to fit a seed tray
- Transplant claws sized for a root ball
- Handles you can grip for a whole shift
- Markers that snap onto a tray edge
- Spacing guides with exact gaps
Six tests on real seedlings
Each test compares your tool with doing the job by hand, so you find out whether the tool is worth making.
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Planting depth
Make a dibbler for one kind of seed, then sow half a tray with it and the other half by finger.
Write downHow many came up in each half, and on which day
-
Smooth surface
Level one tray with your rake or leveler and leave another rough, then sow and water both the same way.
Write downHow many seeds washed into clumps after the first watering
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Transplant
Move ten seedlings with your lifter and ten by hand.
Write downHow many are still upright and green a week later
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Pot packing
Fill six cells with your packer and six by hand, then water them all.
Write downHow far the mix sank in each cell, in millimetres
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Scoop shapes
Make scoops in three different shapes and fill a tray with each.
Write downHow much mix spilled per tray, and which shape disturbed the cells least
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Markers
Clip your markers onto a tray and leave them there through two weeks of watering.
Write downWhich ones are still attached and still readable
Numbers for the nursery bench
Rules growers work by, with where they come from.
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Plant most seeds two to three times as deep as they are wide.
A common rule in university extension gardening guides. Very fine seeds, like lettuce, go almost on the surface.
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Radish and lettuce usually come up within a week in warm mix.
Seed packets and extension guides give about 3 to 10 days at 18 to 24 °C, which is short enough to test a tool and see the result between two workshops.
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Most transplant losses come from damaged roots.
Torn root hairs can't take up water until they grow back, so the seedling wilts even in wet soil. Lifting by the root ball avoids most of the damage.
By the end, you can
- Design a tool around a living plant, not just a material
- Test a tool against doing the same job by hand
- Measure germination and transplant survival
- Tell a grower what your tool saves them, with numbers
Take it into your project
A tool that beats doing the job by hand, with test results to prove it, is something a grower will pay for. Bring those results to module 5 and work out the price.
Ask about this module