Aquaponics - Raising seeds

My experimental seed raising system started nearly two months ago, and consisted of a small seed raising mini-growhouse with an inch of fish tank water in the bottom.

The little growhouse was filled with plastic cups with holes drilled in the bottom. These were filled with scoria as my grow medium.

For the first two months or so everything semed to grow well. I would just drop the seeds on the top of the media, (except for beans, where I added a layer of scoria over the top) and was seeing around 50% success in germination.

The condensation forming inside the mini-growhouse would rain down on the seeds and keep them moist.


Most of what I was growing was basil, and coz lettuce. As the plants got big enough that I thought their tap root reached the bottom of the cup, I'd move them into my NFT tubes.

The interesting thing was that the water stayed fresh.

Very fresh. No smell and it looked clear enough to drink.

Normally water left sitting for months would sour, but even though the water had fish nutrient  (the water was from the fish tank) it stayed sweet.

Pictured here is what it looks like after three months.

Its still surprisingly clear and still has no smell.











I plant coz lettuce every few days to keep a constant supply, but the last few batches haven't done so well, so I thought I'd inspect the growhouse a bit more closely.

It still looks pretty good, but there are some signs of the water going a little slimy. Keep in mind this is the original water.

It's possible that the slime is rotting the seeds before they can germinate, or perhaps it's just that the nutrient is depleted, but I thought I should was it down and start again.

From now on I think I'll clean it every month or so.

It's no great task to was it, but I wanted to see how long it would last. It seems that the cycle of evaporation, condensation, and dripping rain from the ceiling all within the little growhouse has in some way kept everything fresh.

The brown you can see is dirt on the bottom rather than slime growing or fish solids. Some of the original pots for the basil were not cleaned as well as they could have been.


All in all, it's been an interesting experiment, and I can see no reason why it shouldn't continue to be my way of growing lettuce seedlings on an ongoing fashion.

[Not all seeds took well to it. The baby spinach tended to rot before germination, as did larger seeds like rock melon, although both those seed types came from old packets, so it's possible the method had nothing to do with it]


120 Things in 20 years - where shortcuts and time saving, lazy methods of aquaponics, and raising seeds is a way of life.

Aquaponics - Seed raising

I love seeing the first sign of a seed sprouting.

But I don't like how much space an empty pot of gravel takes up, so I came up with a better way.

I've talked before about how I've tried to make my space modular so I can shift plants to places where there is more space when they need it, but keep them packed closely together when they are small, and don't need the space.

My original plan was to use small black plastic pots from my garden store, but now I use plastic cups.

This was partly due to not being able to find a hole cutter that fit the black pots perfectly. The cups are tapered, so will cope with my lack of accuracy with the hole cutter.

They seem to work well, and cost 4 cents instead of 25 per pot.

My original plan was to bury an ice cream container into the main grow bed, and then I could sit the newly seeded pots into it where they would be watered by the flood and drain of the grow bed's cycle.

The problem is, where I would have fit 9 of the black pots, I can only fit 4 of the plastic cups. This means it would take up too much grow bed space to run the intended 18 pots.

The object was to have up to 18 pots with various stages of seed raising from just planted, to a few weeks old. These would be moved to wider spaced holes within the NFT tubes as required, but would take up little space in the meantime.

I own a small seed raising mini-growhouse, so I thought I'd give it a go.

I was hoping that the enclosed design would keep the seeds damp, and keep any pests away.

Sure enough, its a few days later and I see sprouts.

These are all basil, being raised for a new proposed basil section behind my strawberry towers.

Water drips from the roof, and has so far kept all the grow media (scoria in my case) damp. The water that drips from the mini-growhouse ceiling would be basically distilled water, and as such would have no nutrient, but I don't think seeds actually need nutrient for the first few days. I think they live off their stored energy in the seed.

There is around 2cm deep of water in the bottom, and that is probably also contributing to the moisture content as a result of wicking.

I filled the pots nearly to the top, added seeds, then added a layer of scoria. Then I gently watered them in with some water from the fish tank (gently, because it would be easy to wash the seeds away. (no doubt this deposited a small amount of nutrient onto the sroria as well)

My greatest concern was that the nutrient rich water from the fish tank would go rotten because the water was still, but it seems to smell fine after week one, and the seeds are starting to sprout.

I wonder if it's the constant "condensation rain" within the mini-growhouse keeping everything fresh.

Who knows, but it seems to be working.

It will be interesting to see what happens in the next two weeks or so when I it will be time to move them to their new homes. If they avoid growing mouldy, and the water stays fresh, I think I may have solved my seed raising requirements.