Introduction: Indoor Seed Propagator - From Recycled Fruit & Veg Trays and Soda Cans

About: Black sheep engineer, Chartered, and very silly. Currently living in the UK. I have been fortunate to have lived, studied and worked in Hong Kong, Norway and California. I believe physical models help people…

I have to confess, I have a slight 'thing' for getting two different things to work together in a way they were not originally designed for! I made a Butterfly House, in much the same method as this - but realising that two Fruit/Veg Punnets can 'clam-shell' together to produced a Propagator to raise plants indoors.

Better yet by careful selection of various sizes of trays, one can even find:

1. A Transparent Cover
2. A Opaque Growing Tray
3. A Drip Tray for the Growing Tray to sit in.

The trick is pleasingly simple, and especially nice considering this cam be made in about 10minutes (even with an eager toddler beside you!), and cost far less than a shop bought one (around £3-£10, if you include P&P!).

I use this set-up to raise both indoor plants like herbs, but also for propagation in colder month of things that need to go out later in the year. I have also recently used it for taking cuttings of Rosemary.

If you liked it, please consider voting. Thanks =)

(All prizes go to my son - haha! I have not choice - any mail from the USA is too cool not to!)


Two Matching Fruit/Veg Trays or Punnets.
I find Strawberry Punnets are good for the 'cover', and Mushrooms are good for the growing tray.
I'd usually post Amazon links, but clearly in this case, there is no need.
I used sticky tape in the 'quick' version, and a soda can for the 'pro' version.
The can can be cut with scissors, but a craft knife makes it easier to get started!
Pens help for marking up.
Optional: Baggies for spare seeds, spoon for handling seeds. Lollipop sticks for labels.

Step 1: A Note on Seeds, Before We Get Started

I would recommend starting things like Tomatoes, Courgettes and Chillis in such propagators. I've done this for a number of years with great success. (Though I'd previously purchased the propagator trays, but y'know - because COVID!)

Anything with 'Sow Indoors' is a good candidate. But even with 'Sow Outdoor' - such as Peas and Beans, I find you can advance the growing season by at least 1 month indoors. No big deal if you like in Florida, but I'm in the UK, so I need all the Sun I can get!!

The examples shown here I find pretty 'idiot proof' or 'child friendly' - they grow well, require no major skills in transplanting, and once started do well even with a bit of error. Sunflowers also also great!

Step 2: Drainage

Make some holes with knife, scissors or a nail even. It stops things rotting if you over water.

This is also why a drip tray is essential if you do this!

Step 3: Make a Hinge - "Quick Version"

You can use sticky-tape to make a hinge as shown...
- Place boxes side-by-side. Apply tape (ideally wide tape, or use a few pieces if think tape)
- Press down on boxes.
- Close hinge. Apply tape to outer side.
- Press around the edges/flanges of the boxes.
- Done!

But for a better result- make a permanent hinge, which won't degrade with time as much...

Step 4: Make a Hinge: "Pro Version" - From Soda Cans

This makes for a stronger hinge, and I think is a novel application of a soda can in gardening!

Pierce the can with a knife, or scissors, and cut round. Then cut down the side. Again, but round the base ring, to remove a 'sheet' of Aluminium.

Step 5: Making the Hinge Rolls

Taking the 'sheet' of Aluminium, roll tighter as shown.
Warning! The edges will be sharp, so if unsure, use gloves, and even consider goggles just in case it 'springs' up. (I actually do this as a matter of course with my son, as like all 4 year old, he can't be 100% trusted!).
Cut strips about the thickness of your finger - note the direction/curl.
I cut them in half to be about 5cm long.
Roll them tighter again. You can use a pen if it helps to form the roll.

Step 6: Ready to Roll!

Ideally have about 3x hinges per box. Though two will do of course.

Step 7: Hinge Slots

Lay trays side-by-side, and mark 2 or 3 lines on both trays of where you think the hinges will go.
Lay flat, and cut through with a knife, as shown.

Step 8: 'Thread' Hinges Into Trays

Take the roll of metal, and slide into the top (clear) tray.
Thread this through into the growing (opaque) tray.
With the metal roughly divided between either tray, roll it tightly to create a 'lock', as shown.
Squeeze to keep in place. Taking care again with sharp edges.

Step 9: Test Hinge!

Ready to Plant-Up!

Step 10: Recommended: Add a Drip Tray

Using another tray, that has no perforations, to catch drips.
Optional: Suggest using some milk-bottle tops to 'prop-up' the trays, to keep from sitting in water.

Step 11: Compost Time (pt1)

Probably the most fun for my Son ;o)

I useful note, if you fill the tray 2/3 with Multi Purpose Compost, this is a good cheap 'base'....

Step 12: Compost Time (pt2)

...Fill the remaining 1/3 with 'Seedling Compost'. This is more expensive, but good stuff. But there is truthfully not need to fill entire trays with it. Hope this save you some cash in tight times ;o)

Step 13: Pack Down

If you have 2x or more of these, then take one and place on top of the other. This levels off the compost, making it easier to see where seeds are placed/scattered evenly.

Step 14: Seeds - Steady As You Go!

If you have a kid, you probably have these spoons kicking around with no better use. I use them for helping my Son measure out seeds, and not drop / spill them all. Sounds trivial, but avoid frustration at a young age.

Step 15: Cover Up & Pack Down Again

Cover over with the remaining layer of compost. Pack down again.

Often you don't need a whole pack of seeds, so save some for next year. Just re-seal with sticky-tape.

Step 16: Ready!

All we need to do now is water.

Step 17: Water

I'd suggest a good first watering, but check that the drip-tray does not overflow on the first time!
Seed like to soak up water at first, but until germinated, ease off watering a bit, to avoid rot. Just keep damp after that.

Step 18: All Shapes & Sizes

I kinda love that we have a real mix of propagators here, and it'll be interesting to see which works best - high/low roof, etc. We even used loo rolls as mini planters, ready to transplant outside.

Step 19: Window Sill Time!

Grow indoors, until big enough to take outside or to the cold frame if you have one.

Step 20: Coming Through!

It's early days for the seeds in this Instructable Guide, (I'll add updates), but here are some courgettes i started in this way, but without the hinge. Indeed, it kept getting blown/knocked off, so the hinge will really help!

Do please post if you make it, and kindly consider voting if you liked it! Thanks =D

Indoor Plants Challenge

Runner Up in the
Indoor Plants Challenge