Quick and Cheap Propagator!




Me again, just putting together a few photos I have of my propagator I built this summer and of some of the plants that have been grown in it!

This super simple fish tank conversion really helps with growing exotic plants(or anything that doesn't survive Scottish weather) quickly without costing too much and it can be set up in a bedroom where it can be observed constantly.

Altogether I already had most of the parts for this sitting in my garage so it was pretty cheap. I only had to buy the seeding tray and seeds :)

Tuesday 18th December 2012: Featured and on the front page. A huge thanks to everyone who has taken the time to read about my first successful botanic adventure! 

Step 1: Materials:

For this propagator I used:
1 Medium sized fish tank
1 Old water heater from ^fish tank^ (it was spare since the indicator light was broken)
2 bricks with holes in them
Seeding tray

Step 2: Set Up

First, clean out the fish tank or else the water goes all nasty after a few weeks, and place it at a window for some light.

Place the water heater through the holes in the bricks, giving it more surface area than lying on the bottom of the tank, and lower the heating unit into the tank. 
Fill the tank with water until it is just reaching above the bricks, any more may be absorbed by the holes in the seed tray and water log the tray.

plug the heater in and let it heat the water. With the thermometer in the water I think I got it to about 36°C when the air temp was 30°C

Step 3: Sow the Seeds

Place the seed tray in and let the soil heat up a bit before sowing the seeds.

Sow the seeds as you would normally and place the tray on top of the bricks. Place the thermometer on the soil, this will then give a readout of the air temp inside the propagator.

Top this off with the lid of the fish tank and leave to germinate.

Keep checking the thermometer through the glass to see if the water heater needs adjusted.

Step 4: Let Nature Take It's Course!

After a few weeks I got two little sprouts from my bamboo seeds. Only two out of twenty five seeds grew, unfortunately only one plant has survived.

When the first green shoots are about 3-5cm high then it is safe to take the lid off and let more sunlight into the setup.

After re-potting the bamboo shoots I then stuck in a strawberry plant which did ok but I went on holiday and it died (not too fussed it was one out of a million runners from the garden)

Whilst the strawberry plant was in the propagator I added a few orange seeds I had soaked in water for a few days. These sprouted after a while and eventually got re-potted into old herb containers.

Step 5: Products:

Here's just a few photos of how much those tiny little plants have grown over the last 4-6 months:

Step 6: New Projects

To continue the success of my fish tank propagator, I purchased a bag of Flax seeds (linseed) from a local-ish health food store and tried to grow them. Much to my surprise they have sprouted after around a week or so in a small plastic container. Next to them in the photo I am drying out some cherry pits to hopefully grow a mini cherry tree. I don't care if it never produces fruit/ the fruit produced is nothing like the original, I just want to be able to grow the plant and say "I grew that!" I'll keep you updated as things develop. The second photo shows the flax after a few months of growth and the third shows some of my apple trees and pumpkin seeds.

Step 7: The Resurrection

After almost a year, I have dug out the fish tank and a heater and something to prop up a container. This time I'm trying to grow papyrus and after just over a week of waiting, I have a sprout!

Step 8: Need Some Opinions...

Hey guys, with my papyrus growing so well in this setup I'm wondering should I put up more pictures of its progress or should I make a new instructable on growing papyrus?



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    15 Discussions


    Thanks :) I don't know... It shouldn't be that, usually plants don't have any air circulating or at least not much. I'm not really sure, I'm only a beginner in the field of botany :)

    To be honest with you, these things are the first I've not managed to kill :D


    Reply 6 years ago on Introduction

    You do want it warm and humid for your wee ones, but you don't want it too humid. The temperature should be around 20C (70F for the barbarians) but I don't remember exactly the level of humidity - probably somewhat different depending on which plants you're trying to germinate. A newer trend in the hydroponics industry is towards seed tray covers with vent holes and built in thermo-hygrometers so you can monitor the humidity level and keep it in the proper range.

    A very neat idea! I take it you don't have to water due to the large reservoir of warm water, and I am all about being lazy and building systems that take care of themselves. :D


    Reply 6 years ago on Introduction

    I've just hunted down the Growing Guide that came with the seeds and it says:
    "Place the seed trays into a heated propagator or otherwise cover the seeds with a clear plastic lid or bag to retain humidity. Maintain a temperature of around 25-30°C, but no higher as this could damage the seeds."
    I'm pretty sure I kept the soil and air temp at the seeds level at around 30°C but it's all done and in the past so who knows :)

    For the first few weeks when the heater was on and the lid was on I never had to water it. After the lid was removed and the power to the heater cut off I had to start watering the sprouts


    6 years ago on Step 4

    Bamboo is notoriously hard to grow from seed or to propagate! That is why it is so expensive. I have several varieties planted in my yard and I have successfully cut off rhizomes with stalks and grew some nice clumps. I have not found a good source for seeds. Where did you get yours?

    4 replies

    Reply 6 years ago on Introduction

    I keep bamboo (aurea and nigra) in pots - when they get big enough I de-pot them, split them in two, and now have double the bamboo to grow. 11 or so pots worth and will have 22 at the end of next year, assuming I'm not lazy about it. :D Started with one each of the aurea and nigra.


    Reply 6 years ago on Introduction

    Er, meant to add - the main ingredient of my success was installing an automatic watering system. Everything, from bonsai to bamboo, has taken off while I've mostly ignored it due to 60 hour work weeks.


    Reply 6 years ago on Introduction

    I haven't tried that yet.

    I got my seeds from that most wonderful of places, eBay :D


    6 years ago on Step 5

    your seeds may have germinated and died from a thing called damping off. this is caused by too much humidity. which is coming from the evaporating water.


    6 years ago on Introduction

    Very nice instructable, looks like something I might do, except I'm a fish guy and would probably use the tank for fish first. I like your creativity!