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how to start seeds for aquaponics

Stuppy Aquaponics Blog

Over the course of running our system we have tried several ways of introducing plants. It has been fun seeing the differences in time to harvest from each. We initially started by buying rooted starts and planting them in the float and media beds. Similar to field production there is a plateau in growth from the time the plants are planted to when they ramp up the growing pace. This is the acclimating period where the starts are getting used to the new growing media, water, nutrient solution and of course the environment itself. The rooted starts even with the acclimatization period grew to harvest size in a shorter time than if seeded. The down side of this is the rooted starts are more expensive then seeds.

Next we tried germinating seed in the system. We used one inch rockwool plugs in the float and media beds. Each variety of seed had a different germination rate but overall the germination was successful. We seeded two lettuce varieties and basil. In the float bed rockwool was placed in individual sites and seeded. The sites were at harvest spacing, about one and a half square foot each. By doing this the crop was started and harvested from the same site. This didn’t give us the option to start in a nursery and increase the spacing by moving the seedlings to the finish sites when they grew to a certain size. In a trial setting this works out perfectly but if we were pushing the production efficiency we would have missed the two or so weeks we could have finished a crop and started another at the same time.

As the trial of seeding directly into the float bed was finishing we began germinating in the media bed in a couple ways. We set a rockwool slab of plugs even with the media grade to ensure enough moisture was wicked up and seeded enough to populate the float bed. This was done in part to see the germination success in the media bed and to cut the amount of time the plants were in the finishing spacing of the float bed. As mentioned above we were able to grow out one crop and start another in the same system, speeding up the harvest time from crop to crop by a couple weeks.

We also seeded directly into the media bed by simply placing the seed in the expanded clay. Germination was successful but spacing became an issue. Control over where each seed was placed was difficult and depth of seeding was random at best. The seed moved from side to side and ended up at different depths as the seeds were placed and drop through the media. Also because the seeds rooted and grew into the media they were left in place from seeding to harvest. For the quicker crops like lettuce the production time in finish spacing could have been cut if started closer together or in rockwool. For crops like tomatoes this is less of an issue because the crop continues to produce past the first harvest.

As part of pure experimentation we took cuttings from a couple geranium plants, put them in rockwool cubes and planted them in the media bed. No misting was done and the only water they received was from the ebb and flow of the media bed in the system. Rooting happened over a few weeks and new leaves came out. Just like rooting cuttings in typical greenhouse media the geraniums flowered before they would have if started from seed. The cuttings were already in a mature state and did not have to go through the juvenile period as a seedling would have. The geraniums performed very well.

Plants can be added to the system after the fish are added and the bacteria are processing their waste into nitrates. At this point nutrients are present and available to the plants. In our aquaponics curriculum we list out several types of plants best fit for growing in the float and media beds. These plants range from herbs and leafy greens to tomatoes.

Pro Tip: Experiment, play and have fun finding the different ways you can use aquaponics, but track everything. Review the data and improve on what you can. Grow – Iterate – Grow

Starting Plants In Aquaponics: Direct Seeding, Cuttings, Transplanting

Starting Seeds for Aquaponics

There are many methods of starting seeds for aquaponics. I use several but you have to understand I like things orderly and I don’t like to waste seeds.

One method is to sow the seeds directly into the grow bed. Just sprinkle the seeds on the medium and some will find the right conditions, germinate and sprout and some will not. When they get their second set of leaves thin them and you are good to go.

I like to sow my seeds in individual net cups so I can put the plants where I want them or easily move them if I need to. I have used rock wool but I found this product Rapid Root and I have great success with it.

What I am looking for is a base to put my seed so it can germinate. It doesn’t have to be to deep, so I cut the plug in half

Make sure there is a slit in the top about 1/4 to 1/2″ deep depending on the seed requirements. Some seed even require light to germinate and I just lay the seeds on top of the plug. The seed packets don’t always tell the best method to sprout your seeds I rely on a book I got from Park’s Seeds called ‘Success With Seed’ by Karen Park Jennings. It will really help you with your seed starting endeavors.

I take this 1/2 plug and put it in a 3″ net pot surrounded by medium.

So here I have some of the seed I am planting. Swiss Chard, Purple Cauliflower, Cheddar Cauliflower, and Ironman Broccoli are some of my favorites. I plant things you can’t get so easily in a store.
Here is the plug in the net pot with medium surrounding it and I am planting Swiss Chard. It seed is a little bigger and irregular. It likes to be 4 times in depth the size of the seed so I will plant it 1/2″ deep. I usually poke 2 seeds into each plug in case one does not germinate (Most seeds want to be planted 4 time in depth the size of the seed. So if you have a 1/16″ size seed it would be 1/4″ deep).

Here I have some net pots ready with medium and plug. You can see I have plastic name tags for each cup. I put a name and date on each one.

Here is the completed tray of planted seeds. Fill water just so the plug is moist and check every day to make sure they never dry out. You can place the seed trays under lights or if it is the right temperature, put them outside in the sun. You should see sprouts in 3 to 7 days depending on the seeds. However some seeds can take as long as a month to germinate. I find using this method it takes 1/2 the time it take for in potting mix. When the sprouts have 2 sets of leaves thin to one per pot and plant them in your grow beds.

There are many methods of starting seeds for aquaponics. I use several but you have to understand I like things orderly and I don't like to waste seeds. One