DIY Tin Can Herb Planters: Upcycle Cans into a Painted Kitchen Herb Garden
I have a confession. I cannot throw away a good tin can. Diced tomatoes, chickpeas, coffee, it does not matter. If it has a nice shape, it goes into a box in the garage for "someday." This week, someday finally came, and I turned a pile of cans into a row of painted herb planters for the kitchen window.
Tin can herb planters are one of my favorite fall projects. They cost almost nothing, they keep metal out of the trash, and they look great lined up on a sill with basil, parsley, chives and thyme spilling over the edges. The key is doing it right, because a can with no drainage is basically a tiny swamp. Here is my full step-by-step method, plus which herbs grow best indoors in Arizona.
Why Tin Cans Make Great Little Planters
Cans are free, sturdy and a nice size for a single herb plant. A standard 15-ounce can holds about two cups of soil, which is plenty for a small herb that you keep trimmed. Larger cans, like 28-ounce tomato cans or big coffee cans, give roots more room and dry out more slowly, which is helpful in our dry desert air.
They also look charming. Painted in bright colors, wrapped in twine or left with a little brushed-metal shine, a set of matching cans gives your kitchen a farmhouse feel for pennies.
There are a couple of downsides to plan for. Metal heats up fast in direct sun, and bare steel will eventually rust. Both are easy to manage with paint, sealing and smart placement, which I will cover below.
Materials and Tools
Clean, empty tin cans in a few sizes (15-ounce and 28-ounce work well)
A hammer and a large nail, or a drill with a 1/4-inch metal bit
A scrap block of wood to support the can while you punch holes
A can opener that leaves a smooth edge, or a metal file
Fine sandpaper (220 grit) or steel wool
Rust-inhibiting spray primer for metal
Outdoor acrylic craft paint or spray paint
Clear acrylic sealer, matte or gloss
Painter's tape, stencils or paint pens for designs
Small saucers, a tray or jar lids to catch water
Potting mix, ideally one labeled for containers or herbs
Herb seedlings or seeds
Work gloves and safety glasses
Optional extras include twine, chalkboard paint for labels, and a wooden board or tray for a hanging or windowsill display.
Safety First: Sharp Edges
Cut can rims are sharp. I have the scars to prove it. Wear gloves while you work and check the top rim before you do anything else. If your opener left a jagged lip, smooth it with a metal file or press it down flat with pliers. Some newer safety can openers cut along the side of the lid and leave a smooth rim, which makes this step much easier.
Also wear safety glasses when you punch or drill drainage holes. Little metal burrs can fly.
Step 1: Clean and Prep the Cans
Remove the paper labels and soak the cans in hot, soapy water to loosen the glue. A little cooking oil or baking soda paste rubbed on the sticky spots takes off leftover adhesive. Rinse well and dry the cans completely.
Many cans have a thin plastic lining inside. That is fine. You are growing herbs in potting soil, not cooking in them, and the soil does not touch the coating much. Still, I like to use cans that held food rather than chemicals or paint.
Step 2: Add Drainage Holes
This is the most important step, so please do not skip it. Herbs hate wet feet. Without drainage, water pools at the bottom, roots rot and the plant collapses.
Slide a wood block, a scrap 2x4 cut to fit, inside the can so the bottom rests on it. If it will not fit, fill the can with water and freeze it solid. The ice supports the metal so it does not dent.
Use a hammer and a large nail to punch four to six holes around the bottom. Space them evenly, with one in the center.
If you have a drill, a 1/4-inch metal bit makes cleaner holes. Go slow and use light pressure.
Flip the can over and lightly sand any sharp burrs around the holes.
Some people punch a few holes low on the side wall, too, about 1/4 inch above the bottom. That helps water drain even if the can sits in a saucer.
Step 3: Sand and Prime
Lightly scuff the outside of each can with fine sandpaper or steel wool so the paint grips. Wipe off the dust with a damp cloth and let the cans dry.
Then spray on a coat of rust-inhibiting metal primer. Work outside in a well-ventilated spot and set the cans upside down on a piece of cardboard. In Arizona, fall is the perfect time for this, since primer and paint dry fast in our low humidity. Let the primer dry according to the label, usually about an hour.
Step 4: Paint and Decorate
This is where the fun starts. A few design ideas I love:
Solid colors: Paint each can a different shade, like terracotta, sage green, mustard yellow and cream, for a warm desert palette.
Dipped look: Tape off the bottom third and paint just that part a contrasting color.
Stripes and polka dots: Use painter's tape for crisp stripes or the end of a pencil eraser dipped in paint for dots.
Chalkboard labels: Paint a rectangle of chalkboard paint on the front so you can write the herb name.
Rustic twine: Leave the can metallic or paint it white and wrap the middle with jute twine.
Hand-lettered names: Paint pens make it easy to write "basil," "thyme" or "chives" in your best handwriting.
Use two thin coats rather than one thick one, and let each coat dry fully.
Step 5: Seal Against Rust and Water
Once the paint is dry, spray two light coats of clear acrylic sealer over the outside. This protects the paint from water splashes and slows rust. You can also spray a light coat inside along the top inch of the rim, where the soil line will meet the metal.
Let the sealer cure for a full day before planting. I know it is hard to wait.
Step 6: Plant Your Herbs
Add an inch or so of potting mix to the bottom. Skip the gravel layer. It does not actually help drainage and just takes up root space.
Gently remove your herb seedling from its nursery pot and loosen the roots a little.
Set the plant in the can so the top of the root ball sits about half an inch below the rim.
Fill in around it with more potting mix and firm it gently.
Water slowly until a little water runs out of the drainage holes.
Set the can on a saucer, tray or old jar lid to catch drips.
If you are starting from seed, scatter a few seeds over moist potting mix, cover lightly and keep the surface damp until they sprout. Thin to the strongest one or two seedlings per can.
Best Herbs for Tin Can Planters
Small cans work best for herbs that stay compact and that you trim often. Here are my favorites:
Chives: Tough, compact and great snipped over eggs or potatoes.
Parsley: Flat-leaf or curly both do well. Use a larger can because parsley has a long taproot.
Thyme: Loves to dry out between waterings, so it is a natural fit for a sunny sill.
Oregano: Spreads nicely and handles our dry indoor air.
Basil: Wonderful in a sunny window, but it hates cold drafts, so keep it away from leaky winter windows.
Mint: A great choice for a can, because containing mint is the only way to keep it from taking over.
Cilantro and dill: Fun to try, but they grow long taproots and bolt quickly. Give them the biggest cans.
Skip large woody herbs like rosemary and sage in small cans. They grow too big and are happier in a real pot outdoors.
Where to Put Them in an Arizona Home
Herbs indoors need bright light. A south-facing or west-facing window is ideal from fall through spring, when the winter sun sits low in the sky. Aim for at least five to six hours of direct sun. If your windows are shaded, a small LED grow light makes a huge difference.
Be careful in summer. Metal cans on a hot windowsill can get hot enough to cook roots. From May through September, move them back from west-facing glass or switch them to an east window that gets gentle morning light.
Arizona homes are dry, especially with the heater or AC running. Grouping your cans together on a tray creates a little pocket of humidity that herbs appreciate.
You can also take the cans outdoors. In the low desert, fall through spring, they look great hanging on a fence or lined up on a patio table in morning sun.
Watering and Care
Small containers dry out quickly, and metal holds heat, so check your cans every day or two. Stick a finger about an inch into the soil. If it is dry, water until it drains out the bottom. If it is still damp, wait.
Empty the saucers after watering so the cans do not sit in standing water. That is the fastest way to start rust from the bottom up.
Feed with a diluted liquid organic fertilizer about once a month while the herbs are actively growing.
Trim your herbs often. Regular snipping keeps them bushy and compact so they do not outgrow their cans. Pinch off flower buds on basil and mint to keep the leaves coming.
Gift Ideas and Variations
Tin can herb planters make wonderful gifts for teachers, neighbors and holiday swaps. Plant a trio of cans with basil, chives and parsley, tie them up with twine and add a little handwritten care card. You can also mount several cans on a weathered board with screws through the back for a hanging herb garden.
For another easy gift project, check out my DIY mason jar herb kits at https://www.greenthumbhobbies.com/post/diy-mason-jar-herb-kits.
Quick Tin Can Planter Checklist
Clean the cans and smooth any sharp rims
Punch or drill four to six drainage holes
Sand, prime with rust-inhibiting primer and paint
Seal with clear acrylic and let it cure a day
Plant compact herbs in fresh potting mix
Set on saucers and empty them after watering
Give them five to six hours of bright light
Move them away from hot glass in summer
I love walking past my windowsill and snipping a little fresh thyme or chives for dinner, knowing those planters started out as trash. Raid your recycling bin this weekend and make a set of your own. Which herbs would you plant first?
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