Murrays Floating Raft DWC system

[nwestwood]

Are you starting the seedlings in horticubes, between paper towels, in peat moss? I've tried several things and had mixed success. I tried it in the greenhouse with a propagation mat in trays with a cover and . . . they overheated in the day time when the sun was up. Now they are in my house near a window in horticubes, with better success, but still not getting the germination I should (less than 50% and taking 3-5 days to germinate). The batch that was warm is 10 days old and I can see seedlings trying to open, but none are up. For my son's science project a few months ago, I put seeds in miracle grow in net pots and had almost 100% germinate and they sprouted in 2-3 days.

[Murray]

Here are some shots of my seed trays.

learning only to plant a few at a time is the discipline I must learn.

http://aquaponics.net.au/blog/wp-content/uploads/2009/03/seedlings1-400x300.jpg

http://aquaponics.net.au/blog/wp-content/uploads/2009/03/seedlings2-400x346.jpg

[Murray]

The lettuce planted in the floating raft system are going really well.
There is now a reading for NITRITE in the system. Ammonia is still at 1 and there is no nitrates as yet. The EC reading is 1.
There are now 20 x 7 month old Jade Perch in this system.

http://aquaponics.net.au/blog/wp-content/uploads/2009/03/frsystem8-400x300.jpg

Below: Lettuce plants in DWC system.

http://aquaponics.net.au/blog/wp-content/uploads/2009/03/frsystem9-400x300.jpg

Below: Close up of one of the bigger lettuce plants.

http://aquaponics.net.au/blog/wp-content/uploads/2009/03/frsystem10-400x310.jpg

[Dufflight]

If you can control the level of water in the DWC gb you could make up removable FG panels with holes. Ditch the styro. Spaces between the panels could control off gasing of ammonia. Contor the underneath to support the plants. Add a handle in the middle for easy harvest and handling of plants. Easy way to control the batch planting of different crops. And because the panels are sitting on the sides and not the water o2 getting into the water would be improved.

[GaryD]

The method that you've described is commonly used in small-scale hydroponics.

There is no issue with oxygenation in a properly designed raft system....the key is to have sufficient airstones in the grow tank.

I've seen Murray's new set up and, while the styrofoam rafts cover most of the tank surface, there is plenty of air bubbling up through the holes in the rafts.

Gary

[Dufflight]

The styrofoam rafts can get a little messy after a while. Aglae, wear and tear etc. FG panels can be pressure cleaned and sterilized.

For home use having panels that could have a weekly mixture of plants for regular supply sounds like a good idea. Larger scales could also block plants to help plan the flux in usage.

[Murray]

It is true that the rafts could get messy over time, but I feel it is of little concern as the rafts are relatively inexpensive to replace. FG rafts that you suggest would be much higher initial cost.
Aeration is very good in my system, there are 10 air stones in each trough . Every "hole" has air bubbles coming out of it. The air bubbles tend to be dispersed across the surface of the water by the boards close contact woth the water.
I feel the system will prove to be very productive and because of the set layout cause the operator to be well organised.

[aussieap]

The base of the foam has a higher surface area for the bacteria to do their thing. Much of the nitrification in a raft system happens on the walls of the grow bed and base of the foam. The one thing we don't want to do is sterilize the raft whatever it is made of. It will knock out the bio.

How long does it take the water to make one complete circuit of the system Muzz? Is it long enough for those fine solids to mineralize and make those nutrients available in the system water?

Can't wait for this to be available.

[Dufflight]

Plants get diseases that can carry over to the next crop. Cleaning anything that comes into contact with the plants is usually a standard practice. But if you have an idea on how to sterilize half of the foam.
Plus if the panels were just above the water the bubbles breaking the surface would throw fine droplets into the air. Like aeroponics for initial root growth.

[Murray]

Hi Duff,
Sterilisation of equipment is not an issue in aquaponics systems as it is in hydroponics.
Hi Aussie,
How long does it take for the water to make the circuit, don't know exactly, but it would be about 45 to 50 minutes.

[Murray]

Sorry,
I should have been posting about the floating raft system here instead of my regular thread.
However to save re posting it here go to my blog on the floating raft system to take a look.
Blog thread is HERE (http://aquaponics.net.au/blog/?cat=9)

[Castaway]

Hi Murray - How about an update on the Floating Raft system? Hows it coming along? Its about a month since you planted the lettuce and we haven't heard much in the way of progress reports Hows it all shaping up?

Any pictures?

whoops - just read your message above! Sorry

[Murray]

Sorry, I have been posting info about the Floating raft system on my blog and have forgotten to transcribe it over to the forum.
It can be seen here on my blog (http://aquaponics.net.au/blog/?cat=9)


I will move some of the posts over here later on today.

[KenR60]

Hey Murray,
Your Raft System is looking good. Loved the Corn and method of using the Pegs to hold them up!! I wonder if you used a plastic Cup and drilled a hole in the bottom so that this would give the corn about 75mm of support. You could also possibly Split the Cup if you couldn't pass the Corn Roots through the hole, sure the Cup would spring back together again.

[GaryD]

Hi,

Sometimes it's useful to acknowledge that some things grow best in a soil-based growing system......and corn falls into this category along with potatoes and most root crops.

Gary

[fishfood]

Plus one Garry i have always said in an aquaponic setup there should be an soil garden somewere [even if you do water it with fish water]

[Murray]

Sometimes it's useful to acknowledge that some things grow best in a soil-based growing system......and corn falls into this category along with potatoes and most root crops.
Actually, the corn in the floating raft system was transplanted there from one of the regular grow beds to make way for a planting of cabbage, so it was very floppy because of that, and the pegs were used to hold it upright until it re established itself.

I grow corn regularly in my gravel based grow beds with amazing success, in fact it is the best results I have ever had growing corn.
Corn in clay pebbles is not so good.. It grows very well but tends to fall over if there is a bit of wind or whatever. The clay pebbles, because they are round, move around too easily allowing tall type plants to fall over.

I have attempted a corn crop from seedlings in the floating raft already and I would not try it again, same problem as the clay pebbles. Without a support system the corn soon falls over.

[Bubba]

Murray do you have airstones running in the grow beds or is it enough to aerate in the FT?

[Murray]

I have air stones running in the floating raft beds.
I have just cut back on the air as it was a bit to vigorous and plants in the net pots near the air stones were having all the media washed out of the net pot resulting in less than good results.

[aussieap]

I had great results with corn in a gravel growbed last summer. The beds were in a greenhouse so wind damage was never going to be a drama. I transplanted it from seedlings, which I have never had success with before. It seemed to grow quicker than I expected and produced at least 2 ears per plant. I also planted it quite densely, 12-15 plants per bathtub which is a bit closer than I would ordinarily do in a soil garden.

[montreal10]

I have attatched some pics of a small raft system I have. They come as seperate pieces and attached with clips. All plastic.
Laurie.

Hi, where did you buy this floating system?

[montreal10]

Sorry,
I should have been posting about the floating raft system here instead of my regular thread.
However to save re posting it here go to my blog on the floating raft system to take a look.
Blog thread is HERE (http://aquaponics.net.au/blog/?cat=9)

Hi,
You're raft system looks great. I want to start my own and was wondering where you recommend to purchase the supplies (foam, cups, containers..)

[GaryD]

Hi Montreal10,

Welcome to APHQ.

You'll find some of the items you need for a raft system at your local hydroponics store (net pots, etc).

The rafts are made of Styrofoam sheet with holes cut at spacings appropriate to the plants being grown. The Styrofoam sheets are a Dow product.

You can use readymade plastic or fibreglass tanks.....or you can make them yourself using timber or plywood lined with plastic sheet.

Most of the plumbing fittings that you need for a raft system are available from your local hardware merchant.

Gary