Aquaponic Gardening

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Until recently all the work at Coastview Aquaponics has done by our family. Our farm has grown in size and has evolved over the last year. We have improved on the efficiency of our day to day work to save us labor/time. During the evolution of our farm we have constantly been improving on techniques that we have learned. One of our improved techniques is our new seeding process. We have been using this new seeding technique since October 2010 and it has proven itself well over multiple harvests. Now that this technique has proven its self we think it is time to share.

 We used to use a coconut & vermiculite mix in 2" net pots that were placed into 32 cell starter trays. This worked OK for us but we had a poor overall sprouting rate. Sometimes the seeds would sprout then die once touching the coir.  Sometimes we would have a bad block that would not sprout anything at all. We later learned the coconut was imported from overseas.


Here is an example of poor germination with coir mix. Every cell was planted at the same time and only some of them came up.











We began experimenting with alternative medium for seed sprouting. We tried many different mediums and had the best success with black volcanic cinder. This medium is local produced and readily available when living on an active volcano.

Black volcanic cinder is as light as hydroton if not lighter. Lots of it will float if filly flooded. Cinder is very porous and has more surface area than standard gravel. It has excellent wicking capacity in 2" net pots. The cinder is very easy to recycle and use again.

The cinder from the quarry is very dirty with lots of fine material mixed in with it. We screen and wash it to size grade and to remove the sand and silt. The larger cinder is used for gravel beds and the small cinder is used for seeding. The sand/silt is used in our wicking bed medium.

We now use our newly developed technique of seeding net pots directly into our sprouting rafts(2'x2'w/ 61 holes) using cinder as the sprouting medium. We line up 4 rafts at a time, insert net pots, then pour the cinder over tho top of the rafts. Using a small hand broom we broom the cinder into all the net pots and then broom off the excess.We are able to fill 4 rafts(244 net pots) with media in less than 10 minutes.

 Previously we seeded net pots in sprouting trays that would be later transferred into the same rafts after 7-10 days. We now eliminate the labor of transferring from sprouting tray to raft which saves us hours a week. We have shifted away from pelleted seed to using conventional seed(mostly grown by us). Raw seed tends to fall into the voids in the cinder to a perfect depth. The cinder has a wicking capability and if the bottom of the net pot is sitting in water then the seed on top will have adequate moisture for germination without rotting issues. The roots of the plants have all the oxygen they need in the voids of the cinder and grow very quickly.


Seeds germinating out of direct sunlight. I cover with plastic to keep them from drying out. After a 3 day germ I move them to one of the sprouting tables.





















We germinate the seeds our of direct sunlight for 3 days. By then the first seeds are looking for sun and I move them out to the seeding tables. We made custom seeding tables so that they would hold 8 sprouting rafts at 2'x2'. The tables have a constant 1" of water flowing through to provide fresh nutrients to the seedlings. These tables are like a thick NTF table. After two weeks the roots are long enough to need more water and we move the rafts to the nurcedry trough to make way for the next batch of seedlings.


These rafts are floating on 1" of water in custom sprouting tables. This table is a thick NTF table. The sprouts stay here for 2 weeks. We have 2 of these tables.













Here is out nursery trough. The plants grow in here for 2 additional weeks. They then move to the grow out troughs and get spread out to a grow out spacing.

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Replies to This Discussion

Interesting... I am also having germination problems and I have been using coconut fiber.  Where are you buying your volcanic cinder from?  Also what kind of price are you paying?

After reading your post, and no black lava cinders available in my area, I purchased 3 bags of Red Lava rocks (cinders) at Home Depot.  Price was $3.85 a bag. Bag says it will cover 3 sq.ft. 2 inches thick. I spent an hour making little cinders out of big cinders with a large ball pean hammer and a cinder block.  About an hour later I had a 2 gallon bucket full.

My idea is to put a small amount of the coco nut fiber in the 2 inch net pots to keep the cinders and crumbs from falling out the bottom.  I have some wide (about 3 to 4 inch) 2" Dow blue board strips. I purchaded a couple "under the bed" storage bins. I will cut the blue board strips to fit in the storage bins and drill 2 inch holes in them.  I will then pump water from my fish tank using a 70GPH fountan pump into the storage bin which will drain into my grow trough. Hopefully this new media will increase my germination rate.

I found a garden nursery supply place that had 1/4" red and black lava rock called Scoria. I paid 69.00 for a yard.  I use it in germination 32 cell trays with either coco fiber or peat moss to do the same thing as you do to stop the smaller rocks from falling out of the net pots. I am also cutting square screen and putting that into the bottom of the net pots that will eventually replace the media because I am finding that the media eventually falls out after it gets real wet. The germination rate went way up. I then put the 32 cell trays in closed flat trays with water in them so the net pots can wick up to keep the seeds just right. After 2 or 3 days like Steve is doing they are ready for the sun and I take the 32 cell trays out of the flat trays and put them into a shelf trough system I made that also just has enough water in it to keep the net pots or Scoria just moist enough. I have been leaving them in the 32 cell trays until they get to big for them and then take out 16 and still use the 32 cell trays for one more week and then they go into the rafts for completion. I have also made the holes in the bottom of the 32 cell tray about 1" so the roots go into the water and really grow good.

On seeds...I use only open polinated seeds.  If I don' eat it, and I don't sell it, I can always save the seeds. I like and use Annie's Heirloom seeds:

Christian James said:

back to the use of Perlite - I've heard not to use it around fish - breaks down and the fish will eat it


Also, it adds a lot of work, but fluffing the Coco Coir helps after seeding it.  I've tried so many different ways w coir and up until last week was ready to give up on it, but I ordered some new seeds and switched to pelleted seeds, and OMG!  so much better germination rates.  3 of the 4 types I purchased had 100% within a couple of days, and hopefully the fourth variety will catch up.  I highly recommend buying from an online seed company like Johnny's Select Seeds rather than from Home Depot or the like!  you don't know what you're missing!

I now use a mixture of small and medium cinder for seeding instead of just small stuff. My cinder comes 5/8 and smaller. I screen with a piece of lath that removes the 5/8 rocks. Then I screen and wash through a 3/16 screen to remove all the fines. The remaining cinder I use for seeding. The bigger cinder combined with smaller will remain in the net pot better. A little of the smallest cinder will fall out but most of it stays in. I still get good wicking with the mixed sizes.

I use pelleted seed from Johnnies. I seed about 480 net pots a week. The pelleted seed saves me more than an hour each week. Raw seed is difficult for my large fingers to handle and drop one seed in one pot. With raw seed I usually drop in 3-6 in each pot and my fingers cramp up quickly.


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