Killer Seed Propagator

Do you want to know how to increase your success with seed germination? Read on!

As the title of my blog implies, I have way too many hobbies and gardening/hydroponics is one of them!

I set out to build a seed propagator that would create the perfect environment for my precious seeds. It takes care of warmth, watering, light and humidity and is very very simple to build! The system has a small footprint but a high density so that you can grow lots of seeds.

Complete Seed Propagator

Complete Seed Propagator

The design is based on a flood-and-drain (aka ebb-and-flow) system where the lower reservoir holds water or a nutrient solution (plant food) and the water is pumped up to the top tray via a small submersible pump every few hours wher the seed tray soaks up the water it needs.

So that the tray does not overflow, there is an outlet set at a good height that lets the water drain back into the reservoir and recirculate through the system.

Once the pump is switched off, the water drains back out through the pump and lower outlet.

Flood and Drain

Flood and Drain

Since i opted for a more water-tight design, there are rubber grommets around all the fittings to stop leaking. The problem with this is that there will be a tiny amount of water remaining in the top tray after it has drained because the tray is flat.

If the seed trays were placed directly on this puddle of water, they would not have a chance to dry out. Soggy growing media leads to seed rot and mold which is not good for your sensitive seeds.

To solve this issue, i placed another slotted tray inside the top tray so that it sits slightly above the residual water level and allows the growing media to drain sufficiently.

Draining Tray

Draining Tray

Heat is provided by a propagation heat-mat placed underneath the whole system. This provides a good temperature to the water reservoir which couples heat up to the seed tray. This also helps to reduce shock to the seeds caused by watering with cold water.

Humidity is taken care of by a clear plastic top with adjustable vents. This type of lid can typically be found at your hardware store or nursery. It is generally called a humidity dome or similar.

The humidity lid also provides a solid surface to place a compact fluorescent light on for rapid and sustained growth as soon as your seedling exits it’s seed case.

Complete Seed Propagator

Complete Seed Propagator

Light is provided by a low-wattage compact fluorescent with the correct light spectrum for seedlings. It was bought from my favorite shop . Darren and Brett really know their hydroponics and are more than happy to help or just have a chat. If you are local to canberra, i would really suggest you give them a visit at

2/84-86 Wollongong Street Fyshwick ACT 2609
(02) 6239 2598

As a trial run, I have planted Pepper (Piper Nigrum), Lemon Basil (Ocimum × citriodorum), Thyme (Thymus mongolicus) and Ghost Chilli, aka Naga Bhut Jolokia, recognized by Guinness World Records as the hottest pepper in the world.

When the plants start to grow, i will update this blog with pictures and how successful the hydroponic propagator is at germinating seeds.

1 comment

    • Mark on August 13, 2014 at 6:59 am
    • Reply

    How did it go? It looks very good.

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