I believe Rupert (RupertofOz) grew some corn in his media bed with success. Nice to hear you're trying it, Dr. George. I'm thinking that will be a project of mine.
I have been using coconut fiber media since I started a yea ago. Suddenly I am experiencing poor germination. I understand this is common. After some reading I have found some having good results replacing the coconut fiber with black volcanic lava cinders. I am in west centeral FL. Does anyone know a source localy or on the web for black volcanic lava cinders? Also I would like to hear comments from anyone who has switched.
Jordan: The gals at "Green Acres" in Brooksville, FL have a succesfull commercial operation. Gina, may be able to help you out with your business plan.
On pages 6 and 7 of the group's comment wall, a pontoon raft system is described by Giorgio. Seemed like a good idea but I havent heard anything about it since it was originally posted. Anyone tried this?
I am in the designing phase for building two grow beds for a raft system. The rafts need to be elevated about 3 ft off of the ground for accessibility. I took the Friendly 3 day course and have their manual, but they only used ground mounted beds. I would like to use 3/4" 4x8 ft plywood for the bottoms. However, the Friendly beds were 51 inches wide so that they could fully use 48" Dow blue board with some room to spare for easy movement. Does anyone see any issues with cutting down the blue board to approximately 46" other than some loss of area? Also, instead of using a food grade liner I'm thinking of using glass cloth and epoxy for waterproofing the beds and would like to know if this is a good or bad idea. I'm new to the forum, excited to be part of the community...
It shouldn't be to big a deal, but the extra space between the Dow board and the side of the dwc will allow for more light to enter. Thus more algae will grow and compete for nutrients with the plants you are growing. Shouldn't be much an issue but something to think about.
I have built some of the "pontoon rafts". Basically i have built all of them with overall dimension of 2'x4' in a similar construction method as described. I added more support and pontoons. I have different size holes and patterns for varying crop/spacing. My oberservation is: They are sturdy and easy to carry without worry of breakage so durability is good. I used 2" pvc for pontoons and ADDED and extra to the center. So 3 pontoons on each raft. It still sinks down to almost water level with plants/medium and definetly past netcups so you will need rockwool or hydroton with this use. soil is far to wet. I HAVE NEVER USED THE FOAM RAFTS so i have nothing to compare to. I wanted to "do it once, and do it right" and it just seemed this would be a better method than fragil foam. it would seem to me to be better over duration of time but????? feel free to pm for followup in the future. The next ones i will build will probably have a deviation from design to include spacer between pontoon and "frame" of raft. For the cost of larger pvc for pontoon use i would almost bet that empty recycled 2 liter soda bottles wood work much better, cost a fraction compared to say 3" and would have much better buoyancy due to considerably larger diameter. I'd like to have the netcup completely out of the water. I will be using 5 2 liter bottles for new design. one at each corner of frame with a single in the center. hope this helps.
@Arik...Great info, how are you thinking about attaching the soda bottles together? I'm planning on something similar using Nalgene bottles (the ones from the hiking stores), not quite as big, but durable and they have a big, tight lid.
Thanks Arik! So you are happy with the pvc board so far?
Also, one of the reasons Im interested in this method is for the OP's claim that the space between the boards and the water would make extra aeration unnecessary.
Just had a though. Tell me what you all think: In my lastest design, my dwc is going to double as my sump in a pure flood and drain (no siphons, just gravity and a timer) mixed media system Therefore, the water levels in the sump/dwc will fluctuate when the pump is running (which is in the dwc/sump obviously).
My thought is this: In keeping with the idea of no added aeration, what if the entire pvc board was supported with legs as a sort of growing "table" within the dwc? This way, I could have the net pots/roots touching the water when the pump was off (say for 30mins or so depending on the on/off cycle) and then out of or nearly out of the water as the pump was on,lowering the water level. Wouldn't this allow for plenty of air/o2 exchange?
@Joshua...one of the members of the Arizona group (where I'm at) designed a pvc framework in a growbed that extends down to the bottom of the tank....you might check out that board....I can't remember off the top of my head who it was, but someone will know, it's a friendly bunch!
Great link vlad! Im definitely going to experiment with this now. Interesting that the method with the lowest yield is the one that uses a floating board directly on the water. Of course, these are non-circulating systems.
I was also glad to read that the mentioned mosquitos, which was something I was concerned with all along. I think the circulation of water and the addition of guppies and gambusia fish should take care of that.
Hola from Mexico..Interesting link Vlad..There are indeed many ways to get the lettuce on the table..Read sometime back Giorgio's post re pontoon system and thought that might be a good way to go- areate the root systems etc. Had advice from CaryMa re our existing thru-flow ponds and how we might be better off doing a controllable lined pond. If you look at our blog and the aquaponics section at
http://lasenda-ecovillage.blogspot.com/ you'll see our new 45'x105' fish pond which has a 1000 fish or so capacity- we don't want to feed that many..There is also a shot of how our tray system will 'stack' up-each tray will have a adjustable water level by changing standpipes so we can start plants with roots 'in' the water and drop the water level to give them some air. (Joshua- mosquitoes only breed in stagnant water) Our pond water is solar pumped up the hill to the three holding tanks & gravity circulates thru the trays & back to the fish. Changing the water levels in the trays rather than floating the plants seems like a good idea but we have yet to find out to what extent it works. Somehow I feel a bit sorry for a plant stuck in a plastic bottle full of stagnant water - maybe its a healthy way to do it but fresh water flowing thru sure sounds better to me.
@joshua. imho i dont see how the foam could be better as a raft. I would just take 1 litres plastic water bottles or the 2liter as is with cap tight and secure with large zipties. thats it. 5, 2 litres in a pattern like the #5 side of dice under frame. or 1litres around perimeter and down center. same result, much less cash outa pocket imho. i spent hundreds on 2" pipe and caps for pontoons. 2" pipe was not enuf bouyancy/clearance for my liking. netcup is submerged quite a bit still. I have no other oxygenation happening other than the water circulation 24/7. so far plants seem unaffected. the biggest concerns are how to arrange netcup locations depending on anticipated plant size and how the pontoons affect the layout. the outer 3" or so of perimeter of raft are not useable. should be easy to get 40 or so 2" netcups in a 2x4' raft. basically you have to cut the frame pipe sections shorter to compensate for T's so you end up with the overall length at 2'. This way you can cut a single sheet of the polywall material to 2'x4'. I can post the numbers if you need. i dont have commited to memory as i wrote them on a post at the farm. If you quarter the polywall one at a time you can pull the scissors/razor/pocket knife/etc through it very easily. blisters with scissors for sure if you try to scissor your way through them all.
instead of legs like a table, i would place runners to support the rafts. so the rafts ends could "slide" upon them. I- <-- think of the hyphon as pvc pipe. I- -I (front view) think of narrower channel or a center divider that would be there for support/guide. you could just screw some pvc schd40 or something at the height you need in channel to make a lip the raft would sit on and slide down easily. i dont see how the table would allow the rafts to float and move about. cheap and easy. bottles and 1/2pvc. thats pretty cheeap! the 2x4 raft size is super manageable. KISS
Keep it simple. Just use the bottle as is with the cap to seal. attach as many as necessary. now how many do you need? workin on that at the moment. i need all the bottles i can find. Good thing they are abundant! I think the larger 1 litres or 2 litres will work as good or better than 2"pvc at a fraction of cost. I love zipties :)
@Arik...thanks! I am also a big fan of zipties!!! Although in our desert sun and heat they don't last too long, I'm in Scottsdale, AZ, maybe submersed or partially submersed they will have a longer life.
I guess my initial idea was to have the growing area stationary (like a table) and just have it at a permanent height to allow the rising and falling water level aerate and feed/water the roots. However, in vlad's link, they stated that plants that were on large floats (like Arik's soda bottles) whose roots which were partially submerged had essentially two main root zones: The area that was above water was the "oxygen roots" section and below that were the submerged nutrient roots.
I wonder if its more beneficial to the plants to designated nutrient and oxygen root sections or to have the entire root system both oxygenate and absorb water nutrients as in my "table" idea. Maybe i'll experiment with both methods to see what's better.
the roots exposed to the "air" will harden a bit and will take up the bulk of the oxygen. they will still also absorb moisture due to high humidity in this area of the rootzone. the roots will "chase" the moisture down and submerge. Let nature do its thang. heres the test rafts. Ideally i want the netcup bottom above the water level. these were completed a couple weeks ago. i'll be playing with 2 litres or other similar abundant bottles to work this out. cycling.jpg
I've bitten the bullet and built a 4'x8' DWC trough and tables/rafts. See the photos.
What I really need to know now is, what media do I use in the pots? I'm giving lava rock topped with pearlite a try, but I'm not sure that'll work.
What is everyone else using in the pots?
I've got the water level set to touch or just enter the bottom of the pots by a quarter inch or so. This seems to keep the media in the pot nice and damp. Any suggestions here would be great too.
Complete newbie at DWC here and need all the info I can get.
I've got 1" sized lava rock and I fear that the seeds are going to fall through.
I like to keep the seeds cozy, you know. It's a personal failing: I still have severe doubts every time I throw seeds into the lava rock media beds. I shouldn't, because they always seem to grow, but being a farmer's kid, it just doesn't seem right.
Maybe, I'll crush up some of the lava rock to a smaller size and give that a run.
I grow out my seedlings in a mixture of cocnut coir, vermiculite and worm casting (secret ingredient) and transfer the entire "plug" into the net pots. Since 98 cell propagation trays require less space than a DWC, you can get a higher turn on your DWC production.
I tried small gravel in addition and then had to send a bunch of wasted time at the harvest end.
I have been using starter plugs from IHort, make from bark and a sponge polymer, in 392 cell trays, (that's right, 392 cells, 14 x 28 grid in a 13" x 26" tray), and they fit directly into the industry standard 1" tapered holes in Beaver Plastic EPS rafts, no chunks or rocks to fall into the water, and the whole thing gets pulled with the produce and stays on for the consumer to compost.
Now, however, I'm gearing towards Organic Cert, and I'm playing with using the same trays and filling them with seasoned biochar bits. So good so far, and I expect the seedling roots will hold and contain the lightweight char, and again the end consumer can add them to their compost.
Raychel, I have been using only lava for seeding. Most small seeds fall into the voids and plant themselves when I top water. The best thing about lava is it is easily recyclable!!!! I have been using the sane lava for years. I figure that I loose less than 10 in the root-balls after harvest. I can get a cubic yard of it for about 60$ which makes it the most economical choice for me.
In high production systems, like Chris's system, cost will of course become a major factor for choice of media. Here in my country Coir is a cost choice but the drawback is the frequent turnover rate.
Mahalo Chris. Like others I used a mixture of vermiculite, coir, and some organic potting mix with the cinders. You have given me hope again because the other stuff just washes away in the water. Do you have a seeding table or do you just put them in the blue dow
Raychel, I seed net pots full of cinders in rafts then top water with system water and keep them out of the system sandwiched in plastic to keep in moisture in a shady area for germination. For most verities of leafy greens I have seeds popping in three days then I put them into a shallow trough for three weeks. Then they go to the trough at grow-out spacing. I have a complete description of my process in Coastview Aquaponics group. That posting was made several years ago and I still use the same technique today since it works so for me!
After getting feedback from this group I thought I'd tell what I did and show the results.
I got out my hammer and spent a 'fun' half hour smashing my largish 1" lava rock down to around 1/4" and less. It wasn't all that difficult but if you've got access to cinders of the right size, I'd recommend skipping the hammer.
Instead of putting the pots in the DWC bed I put them in a plastic tray and filled it with fish tank water to about 1" deep and put the clear plastic cover over the top. After a couple of days I thought I saw one of the seeds going moldy (I'm not sure, but it looked like it, and I lost a whole bunch of bean seeds last year to mold from been too wet, so I'm a bit gun-shy) so I took the plastic cover off and kept the water topped up.
In about 4 days I had shoots showing in most of the pots and in 1 week I have seedlings in ALL of the pots. Needless to say, I'm impressed. I must confess at this point that I was quite dubious about this process so sowed way too many seeds in each pot, probably 4-5+, but I don't mind. Seeds are cheap and having 100% hit rate on the pots is very satisfying.
Thanks to all who contributed suggestions. It is appreciated.
John, I did something similar recently with similar results. Takes a little work to figure out the details to this planting technique for each seed but nothing good comes easy.
Does anyone live in Michigan near Ottawa County??? I need someone with experience to help me as I am at a loss with saving our plants. If there is a mold problem do you take out all the plants?? What do you do. We finally had a few grow into somewhat of a lettuce but are now also turning brown. I am getting so frustrated as I have poured everything into them and it's utterly failing.
@Tarah Bertsch - A few pictures would help, but I'll go out on a limb and guess that the plants shriveled up near the top of the net pot media. It's probably too late to save your plants, but you should remove infected plants, and sanitize with a 3% hydrogen peroxide using a spray bottle.
I am in the late stages of design on my system before I start purchasing and building still need ALOT of advice on the best ways and what just wont work. Love the Poly Pvc "raft" idea! Letting the raft be a fixed height and not float and using a pvc drain tube to get the idea water height which from reading is less then 1/3 of the 2 inch net pot? My main question is has anyone ever experimented with shrimp in DWC troughs? It seems like a lot of square feet on the bottom of the troughs not being used. Tilapia and shrimp both like the same water temps and shrimp feed off the waste in the system and will clean off the plan roots. My main concerns are will the shrimp breed to sustain the population and which variety of shrimp would "taste" best. Also how deep do the deep water culture troughs need to be 16 inches enough or should I think more like 24 inches? Thank you
I have never tried rasing shrimp but I was told that you need allot of space to even get a fair size harvest due to the fact they eat each other when in close quarters. They have been raised in 12" deep troughs right along with the floating rafts and did fine except for the loss of them eating each other.
Well that sheds new light on my thoughts. Maybe putting some netting to keep them off the roots but is it worth it at that point. Anyone put rock on the bottom to help act as a bio filter? I am planning a very high fish stock density going to make a swirl filter, sand and possible a bio filter before I dump into a media filled bed that letting that drop into my DWC possibly letting that dump into a sump if need? Then pumping back to the fish tanks.
I believe a couple inches of gravel would be a very good idea.
The experts might say I was lucky, but I placed about 18" of pumice in the bottom of my 48" deep fish tank. The 2" pickup tube was buried on one end of the 10' long tank. The water came in at the bottom below the pumice through a 10 ft length of perforated drain pipe. So all the water (about 300 gal/hour) had to flow through the pumice.
After about 9 months I emptied the tank, and there was no foul smell. There were 60 tilapia, 30 of them fully grown in the tank the rest about 6" long. I lost one fish during that period. The trick is circulation although there must have been some dead spots in my tank.
I live in the Caribbean and we have to import all of our materials. I am in the works of designing/ pricing out a commercial aquaponics system and would like there to be a large raft component and was wondering if anyone had any suggestions on raft materials? I am currently using 1" dow blue board as I can get that from our hardware store but if there is a cheaper alternative that I can import from the states that would be great. Any suggestions?
I also live in the Caribbean, Curacao. I find that grapes are imported in foam container consisting of two half's. I use these to make 2" holes as use them as floaters/rafts. Works perfectly and I get them at the supermarkets for free. The lit I use without modification. The bottom part has more foam material and drift higher so that the bottom of the net pot does not touch the water. So I cut 2 cm off. I'll post some pictures tomorrow.
Eric Warwick
I believe Rupert (RupertofOz) grew some corn in his media bed with success. Nice to hear you're trying it, Dr. George. I'm thinking that will be a project of mine.
Jul 27, 2012
Dave Lindstedt
I have been using coconut fiber media since I started a yea ago. Suddenly I am experiencing poor germination. I understand this is common. After some reading I have found some having good results replacing the coconut fiber with black volcanic lava cinders. I am in west centeral FL. Does anyone know a source localy or on the web for black volcanic lava cinders? Also I would like to hear comments from anyone who has switched.
Jul 28, 2012
Dave Lindstedt
Jordan: The gals at "Green Acres" in Brooksville, FL have a succesfull commercial operation. Gina, may be able to help you out with your business plan.
Jul 28, 2012
Josh
Hi all,
On pages 6 and 7 of the group's comment wall, a pontoon raft system is described by Giorgio. Seemed like a good idea but I havent heard anything about it since it was originally posted. Anyone tried this?
Sep 7, 2012
Pat Moore
I am in the designing phase for building two grow beds for a raft system. The rafts need to be elevated about 3 ft off of the ground for accessibility. I took the Friendly 3 day course and have their manual, but they only used ground mounted beds. I would like to use 3/4" 4x8 ft plywood for the bottoms. However, the Friendly beds were 51 inches wide so that they could fully use 48" Dow blue board with some room to spare for easy movement. Does anyone see any issues with cutting down the blue board to approximately 46" other than some loss of area? Also, instead of using a food grade liner I'm thinking of using glass cloth and epoxy for waterproofing the beds and would like to know if this is a good or bad idea. I'm new to the forum, excited to be part of the community...
Sep 9, 2012
Josh
Sep 10, 2012
Arik Alan
I have built some of the "pontoon rafts". Basically i have built all of them with overall dimension of 2'x4' in a similar construction method as described. I added more support and pontoons. I have different size holes and patterns for varying crop/spacing. My oberservation is: They are sturdy and easy to carry without worry of breakage so durability is good. I used 2" pvc for pontoons and ADDED and extra to the center. So 3 pontoons on each raft. It still sinks down to almost water level with plants/medium and definetly past netcups so you will need rockwool or hydroton with this use. soil is far to wet. I HAVE NEVER USED THE FOAM RAFTS so i have nothing to compare to. I wanted to "do it once, and do it right" and it just seemed this would be a better method than fragil foam. it would seem to me to be better over duration of time but????? feel free to pm for followup in the future. The next ones i will build will probably have a deviation from design to include spacer between pontoon and "frame" of raft. For the cost of larger pvc for pontoon use i would almost bet that empty recycled 2 liter soda bottles wood work much better, cost a fraction compared to say 3" and would have much better buoyancy due to considerably larger diameter. I'd like to have the netcup completely out of the water. I will be using 5 2 liter bottles for new design. one at each corner of frame with a single in the center. hope this helps.
Sep 10, 2012
Chris George
@Arik...Great info, how are you thinking about attaching the soda bottles together? I'm planning on something similar using Nalgene bottles (the ones from the hiking stores), not quite as big, but durable and they have a big, tight lid.
Sep 10, 2012
Josh
Thanks Arik! So you are happy with the pvc board so far?
Also, one of the reasons Im interested in this method is for the OP's claim that the space between the boards and the water would make extra aeration unnecessary.
Are you aerating?.
Sep 10, 2012
Josh
Just had a though. Tell me what you all think: In my lastest design, my dwc is going to double as my sump in a pure flood and drain (no siphons, just gravity and a timer) mixed media system Therefore, the water levels in the sump/dwc will fluctuate when the pump is running (which is in the dwc/sump obviously).
My thought is this: In keeping with the idea of no added aeration, what if the entire pvc board was supported with legs as a sort of growing "table" within the dwc? This way, I could have the net pots/roots touching the water when the pump was off (say for 30mins or so depending on the on/off cycle) and then out of or nearly out of the water as the pump was on,lowering the water level. Wouldn't this allow for plenty of air/o2 exchange?
Sep 10, 2012
Chris George
@Joshua...one of the members of the Arizona group (where I'm at) designed a pvc framework in a growbed that extends down to the bottom of the tank....you might check out that board....I can't remember off the top of my head who it was, but someone will know, it's a friendly bunch!
Sep 10, 2012
Vlad Jovanovic
http://www.ctahr.hawaii.edu/hawaii/downloads/Three_Non-circulating_...
@Chris...I think it was Larry in Casa Grande (Arizona AP) who built such a PVC framework...
Sep 10, 2012
Chris George
@Vlad...thanks, I thought it was Larry in CG....but I was headed out the door and didn't have time to check. Great link, too, I'm reading it now.
Sep 10, 2012
Josh
Great link vlad! Im definitely going to experiment with this now. Interesting that the method with the lowest yield is the one that uses a floating board directly on the water. Of course, these are non-circulating systems.
I was also glad to read that the mentioned mosquitos, which was something I was concerned with all along. I think the circulation of water and the addition of guppies and gambusia fish should take care of that.
Thanks again!
Sep 10, 2012
Rick Welland
Hola from Mexico..Interesting link Vlad..There are indeed many ways to get the lettuce on the table..Read sometime back Giorgio's post re pontoon system and thought that might be a good way to go- areate the root systems etc. Had advice from CaryMa re our existing thru-flow ponds and how we might be better off doing a controllable lined pond. If you look at our blog and the aquaponics section at
http://lasenda-ecovillage.blogspot.com/ you'll see our new 45'x105' fish pond which has a 1000 fish or so capacity- we don't want to feed that many..There is also a shot of how our tray system will 'stack' up-each tray will have a adjustable water level by changing standpipes so we can start plants with roots 'in' the water and drop the water level to give them some air. (Joshua- mosquitoes only breed in stagnant water) Our pond water is solar pumped up the hill to the three holding tanks & gravity circulates thru the trays & back to the fish. Changing the water levels in the trays rather than floating the plants seems like a good idea but we have yet to find out to what extent it works. Somehow I feel a bit sorry for a plant stuck in a plastic bottle full of stagnant water - maybe its a healthy way to do it but fresh water flowing thru sure sounds better to me.
Sep 10, 2012
Arik Alan
@joshua. imho i dont see how the foam could be better as a raft. I would just take 1 litres plastic water bottles or the 2liter as is with cap tight and secure with large zipties. thats it. 5, 2 litres in a pattern like the #5 side of dice under frame. or 1litres around perimeter and down center. same result, much less cash outa pocket imho. i spent hundreds on 2" pipe and caps for pontoons. 2" pipe was not enuf bouyancy/clearance for my liking. netcup is submerged quite a bit still. I have no other oxygenation happening other than the water circulation 24/7. so far plants seem unaffected. the biggest concerns are how to arrange netcup locations depending on anticipated plant size and how the pontoons affect the layout. the outer 3" or so of perimeter of raft are not useable. should be easy to get 40 or so 2" netcups in a 2x4' raft. basically you have to cut the frame pipe sections shorter to compensate for T's so you end up with the overall length at 2'. This way you can cut a single sheet of the polywall material to 2'x4'. I can post the numbers if you need. i dont have commited to memory as i wrote them on a post at the farm. If you quarter the polywall one at a time you can pull the scissors/razor/pocket knife/etc through it very easily. blisters with scissors for sure if you try to scissor your way through them all.
Sep 10, 2012
Arik Alan
@Joshua
instead of legs like a table, i would place runners to support the rafts. so the rafts ends could "slide" upon them. I- <-- think of the hyphon as pvc pipe. I- -I (front view) think of narrower channel or a center divider that would be there for support/guide. you could just screw some pvc schd40 or something at the height you need in channel to make a lip the raft would sit on and slide down easily. i dont see how the table would allow the rafts to float and move about. cheap and easy. bottles and 1/2pvc. thats pretty cheeap! the 2x4 raft size is super manageable. KISS
Sep 10, 2012
Arik Alan
@Chris.
Keep it simple. Just use the bottle as is with the cap to seal. attach as many as necessary. now how many do you need? workin on that at the moment. i need all the bottles i can find. Good thing they are abundant! I think the larger 1 litres or 2 litres will work as good or better than 2"pvc at a fraction of cost. I love zipties :)
Sep 10, 2012
Chris George
@Arik...thanks! I am also a big fan of zipties!!! Although in our desert sun and heat they don't last too long, I'm in Scottsdale, AZ, maybe submersed or partially submersed they will have a longer life.
Sep 10, 2012
Josh
Great info everyone!
I guess my initial idea was to have the growing area stationary (like a table) and just have it at a permanent height to allow the rising and falling water level aerate and feed/water the roots. However, in vlad's link, they stated that plants that were on large floats (like Arik's soda bottles) whose roots which were partially submerged had essentially two main root zones: The area that was above water was the "oxygen roots" section and below that were the submerged nutrient roots.
I wonder if its more beneficial to the plants to designated nutrient and oxygen root sections or to have the entire root system both oxygenate and absorb water nutrients as in my "table" idea. Maybe i'll experiment with both methods to see what's better.
Sep 11, 2012
Arik Alan
the roots exposed to the "air" will harden a bit and will take up the bulk of the oxygen. they will still also absorb moisture due to high humidity in this area of the rootzone. the roots will "chase" the moisture down and submerge. Let nature do its thang. heres the test rafts. Ideally i want the netcup bottom above the water level. these were completed a couple weeks ago. i'll be playing with 2 litres or other similar abundant bottles to work this out. cycling.jpg
Sep 11, 2012
John Malone
Hello All,
I've bitten the bullet and built a 4'x8' DWC trough and tables/rafts. See the photos.
What I really need to know now is, what media do I use in the pots? I'm giving lava rock topped with pearlite a try, but I'm not sure that'll work.
What is everyone else using in the pots?
I've got the water level set to touch or just enter the bottom of the pots by a quarter inch or so. This seems to keep the media in the pot nice and damp. Any suggestions here would be great too.
Complete newbie at DWC here and need all the info I can get.
Thanks. John
Apr 8, 2013
Daniel Judy
Nice setup! I'm using coconut coir and perlite, mixed about 3:1 or 4:1. It's been working fine with basil and lettuce.
Apr 8, 2013
Vlad Jovanovic
John...why not just use your lava rock? Why the hassle with the perlite or anything else?
Apr 8, 2013
John Malone
I've got 1" sized lava rock and I fear that the seeds are going to fall through.
I like to keep the seeds cozy, you know. It's a personal failing: I still have severe doubts every time I throw seeds into the lava rock media beds. I shouldn't, because they always seem to grow, but being a farmer's kid, it just doesn't seem right.
Maybe, I'll crush up some of the lava rock to a smaller size and give that a run.
Apr 8, 2013
Chris Smith
John, lava rock is easily crushed with a hammer to make smaller pieces. Try breaking some up for seeding. I have been doing this for years!
Apr 9, 2013
Raychel A Watkins
Hey Chris Do you use only lava rock in your net pots or do you add something like coir.
Apr 9, 2013
Ned Berndt
Hey John,
I grow out my seedlings in a mixture of cocnut coir, vermiculite and worm casting (secret ingredient) and transfer the entire "plug" into the net pots. Since 98 cell propagation trays require less space than a DWC, you can get a higher turn on your DWC production.
I tried small gravel in addition and then had to send a bunch of wasted time at the harvest end.
Best regards,
Ned
Apr 9, 2013
Jon Parr
I have been using starter plugs from IHort, make from bark and a sponge polymer, in 392 cell trays, (that's right, 392 cells, 14 x 28 grid in a 13" x 26" tray), and they fit directly into the industry standard 1" tapered holes in Beaver Plastic EPS rafts, no chunks or rocks to fall into the water, and the whole thing gets pulled with the produce and stays on for the consumer to compost.
Now, however, I'm gearing towards Organic Cert, and I'm playing with using the same trays and filling them with seasoned biochar bits. So good so far, and I expect the seedling roots will hold and contain the lightweight char, and again the end consumer can add them to their compost.
Apr 9, 2013
Chris Smith
Raychel, I have been using only lava for seeding. Most small seeds fall into the voids and plant themselves when I top water. The best thing about lava is it is easily recyclable!!!! I have been using the sane lava for years. I figure that I loose less than 10 in the root-balls after harvest. I can get a cubic yard of it for about 60$ which makes it the most economical choice for me.
Apr 9, 2013
Harold Sukhbir
Hi All,
In high production systems, like Chris's system, cost will of course become a major factor for choice of media. Here in my country Coir is a cost choice but the drawback is the frequent turnover rate.
Apr 9, 2013
Raychel A Watkins
Mahalo Chris. Like others I used a mixture of vermiculite, coir, and some organic potting mix with the cinders. You have given me hope again because the other stuff just washes away in the water. Do you have a seeding table or do you just put them in the blue dow
Apr 9, 2013
John Malone
And the DWC raft build is complete. It took a lot longer than I expected.
104 holes of goodness.
Apr 13, 2013
Chris Smith
Raychel, I seed net pots full of cinders in rafts then top water with system water and keep them out of the system sandwiched in plastic to keep in moisture in a shady area for germination. For most verities of leafy greens I have seeds popping in three days then I put them into a shallow trough for three weeks. Then they go to the trough at grow-out spacing. I have a complete description of my process in Coastview Aquaponics group. That posting was made several years ago and I still use the same technique today since it works so for me!
Apr 14, 2013
Bob Campbell
@Chris Smith - I looked through all the discussions in Coastview Aquaponics group, and your web site, but could not find your post about starts.
Apr 14, 2013
Chris Smith
Sorry it was in the raft/dwc group. Here is a link.
Apr 14, 2013
Dr. George B. Brooks, Jr.
Just a fun pic from today.
Apr 19, 2013
John Malone
Starting tomato seeds
After getting feedback from this group I thought I'd tell what I did and show the results.
I got out my hammer and spent a 'fun' half hour smashing my largish 1" lava rock down to around 1/4" and less. It wasn't all that difficult but if you've got access to cinders of the right size, I'd recommend skipping the hammer.
Instead of putting the pots in the DWC bed I put them in a plastic tray and filled it with fish tank water to about 1" deep and put the clear plastic cover over the top. After a couple of days I thought I saw one of the seeds going moldy (I'm not sure, but it looked like it, and I lost a whole bunch of bean seeds last year to mold from been too wet, so I'm a bit gun-shy) so I took the plastic cover off and kept the water topped up.
In about 4 days I had shoots showing in most of the pots and in 1 week I have seedlings in ALL of the pots. Needless to say, I'm impressed. I must confess at this point that I was quite dubious about this process so sowed way too many seeds in each pot, probably 4-5+, but I don't mind. Seeds are cheap and having 100% hit rate on the pots is very satisfying.
Thanks to all who contributed suggestions. It is appreciated.
Apr 28, 2013
Dr. George B. Brooks, Jr.
John, I did something similar recently with similar results. Takes a little work to figure out the details to this planting technique for each seed but nothing good comes easy.
May 7, 2013
Tarah Bertsch
Does anyone live in Michigan near Ottawa County??? I need someone with experience to help me as I am at a loss with saving our plants. If there is a mold problem do you take out all the plants?? What do you do. We finally had a few grow into somewhat of a lettuce but are now also turning brown. I am getting so frustrated as I have poured everything into them and it's utterly failing.
Jul 1, 2013
Bob Campbell
@Tarah Bertsch - A few pictures would help, but I'll go out on a limb and guess that the plants shriveled up near the top of the net pot media. It's probably too late to save your plants, but you should remove infected plants, and sanitize with a 3% hydrogen peroxide using a spray bottle.
Here's one of many threads about pythium
http://community.theaquaponicsource.com/forum/topics/the-dreaded-py...
Here's a search on this site
http://community.theaquaponicsource.com/main/search/search?q=pythium
Jul 1, 2013
Tim Sumrall
My first raft of basil. It's 4 weeks old today. I have a second raft in at 2 weeks old and enough pots started for a third.
Jul 11, 2013
Tray Rasco
I am in the late stages of design on my system before I start purchasing and building still need ALOT of advice on the best ways and what just wont work. Love the Poly Pvc "raft" idea! Letting the raft be a fixed height and not float and using a pvc drain tube to get the idea water height which from reading is less then 1/3 of the 2 inch net pot? My main question is has anyone ever experimented with shrimp in DWC troughs? It seems like a lot of square feet on the bottom of the troughs not being used. Tilapia and shrimp both like the same water temps and shrimp feed off the waste in the system and will clean off the plan roots. My main concerns are will the shrimp breed to sustain the population and which variety of shrimp would "taste" best. Also how deep do the deep water culture troughs need to be 16 inches enough or should I think more like 24 inches? Thank you
Jul 23, 2013
wes
I have never tried rasing shrimp but I was told that you need allot of space to even get a fair size harvest due to the fact they eat each other when in close quarters. They have been raised in 12" deep troughs right along with the floating rafts and did fine except for the loss of them eating each other.
Jul 24, 2013
wes
Go here and see what he was up against with raising prawns.
http://apnko.com/en/blog/entry/something-is-eating-my-roots-part-2
Jul 24, 2013
Tray Rasco
Well that sheds new light on my thoughts. Maybe putting some netting to keep them off the roots but is it worth it at that point. Anyone put rock on the bottom to help act as a bio filter? I am planning a very high fish stock density going to make a swirl filter, sand and possible a bio filter before I dump into a media filled bed that letting that drop into my DWC possibly letting that dump into a sump if need? Then pumping back to the fish tanks.
Jul 25, 2013
Tray Rasco
Is the 45 mil DuPont http://www.bestnest.com/bestnest/RTProduct.asp?SKU=FIR-W56PL41075 needed for the DWC beds or will http://www.globalplasticsheeting.com/aquaponics-plastic-film/ something like that in 24 mill work just fine? What is the life span on those in a greenhouse.
Jul 25, 2013
Bob Campbell
@Tray
I believe a couple inches of gravel would be a very good idea.
The experts might say I was lucky, but I placed about 18" of pumice in the bottom of my 48" deep fish tank. The 2" pickup tube was buried on one end of the 10' long tank. The water came in at the bottom below the pumice through a 10 ft length of perforated drain pipe. So all the water (about 300 gal/hour) had to flow through the pumice.
After about 9 months I emptied the tank, and there was no foul smell. There were 60 tilapia, 30 of them fully grown in the tank the rest about 6" long. I lost one fish during that period. The trick is circulation although there must have been some dead spots in my tank.
Jul 25, 2013
Mathew Slattery
I live in the Caribbean and we have to import all of our materials. I am in the works of designing/ pricing out a commercial aquaponics system and would like there to be a large raft component and was wondering if anyone had any suggestions on raft materials? I am currently using 1" dow blue board as I can get that from our hardware store but if there is a cheaper alternative that I can import from the states that would be great. Any suggestions?
Nov 22, 2013
Henny Barbolina
I also live in the Caribbean, Curacao. I find that grapes are imported in foam container consisting of two half's. I use these to make 2" holes as use them as floaters/rafts. Works perfectly and I get them at the supermarkets for free. The lit I use without modification. The bottom part has more foam material and drift higher so that the bottom of the net pot does not touch the water. So I cut 2 cm off. I'll post some pictures tomorrow.
Nov 22, 2013