A Community and Forum For Aquaponic Gardeners

pros and cons of using styrofoam as rafts

I bought the cheaper styrofoam insulation sheets from Lowes. I got some that were 3/4 inch on sale, and some slightly thinner ones later. Both have faired almost the same.

I am using IBCs as growbeds, so to maximize each 4 X 8 sheet, I cut them 32 inches wide and then adjuSted the length to just fit into the IBC's.

I wanted an air gap under each plate, so I used a length of PVC pipe with a cord running through it so it could be tied to the IBC frame. That way I could adjust the gap as needed. I put those supporting pipes about 6 inches from each end. (That was where I had left bars on the frames above the rim of the tub.)

At first, it looked great. Then I started planting and my lessons began... :D

First off, the 30" or so length of unsupported raft was too much so it began to sag in the middle. I remedied this somewhat by using the scraps of styrofoam as floats in the middle. I also found swimming pool 'noodles' on sale last winter for $2 each. Cut in 1/2, they make a fair support...for a while. Did you know they actually will shrivel up over time?

Next, there is a thin plastic coating on the white side of the styrofoam that does not last long in sunlight. It gets brittle and flakes like snakeskin. So that got removed with a garden hose onto the lawn. better there than the AP system.

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Replies to This Discussion

Permalink Reply by Teresa Barber on August 26, 2013 at 9:19am

I can not reference the white film on the foam board. You may want to post brand name here so we can avoid in the future, but in most cases 2 inch foam board is used on most commercial farms. Thicker board is self supporting.

Permalink Reply by Ned Berndt on August 26, 2013 at 9:44am

Hi Pat,

I would only use 2" DOW blue board for rafts:

1) lasts a long time and will not fall apart.

2) Rigid enough for a 2'x4' raft

3) Stands up to 2" hole saw well.

4) easily painted white

Best regards,

Ned

Permalink Reply by Jim Troyer on August 26, 2013 at 1:41pm

I'm going with Ned

Styrofoam is not worth the money for this process.

2" blue board is good, it doesn't sink under the weight of the plants.

I would suggest that you consider some suspended rafts too. Make a lip around the inside of your tote and set a panel on it. The height is fixed and can be easily adjusted with shims to figure out what works best. Studies have shown that an air gap is worth working for.

Permalink Reply by Pat James on August 26, 2013 at 4:04pm

Jim, I was trying to get the rafts suspended. I took a pvc pipe, strung a line through it and put the board on top. I held high enough on the ends but the middle sagged. I am just going to have to spend the money for the better product..

Plus after taking out all my 3/4 inch pipe, I have extra to build a better support support.

Permalink Reply by Lisa M. Johnson on August 26, 2013 at 5:24pm

Aloha,

The thin styrofoam is not a good plan. I am replacing mine with Dow board. Most of my system has Dow blue board and it holds up great. The thinner foam with silver reflective top is the boards I am replacing. The board gets very soggy with water and who knows what else it absorbs. I emptied the older ones about one year old first and found they were very weighted with water. The ones I had added last were not as bad but definitely on there way to being very weighted. If you have the choice go with the Dow board or you will be replacing the cheaper ones soon than later.

Permalink Reply by Pat James on August 27, 2013 at 7:17am

Going to stop by Home Depot on my home from work and price blue board. I got his other because it was around $12 a sheet.

How do you prefer to cut the holes? Hole saw or do you burn them? Also, what size net pots are you using? I have several hundred 2" pots.

Permalink Reply by Lisa M. Johnson on August 27, 2013 at 6:17pm

I use a hole saw and I use 2" pots about 5000 of them. I also have some 3" holes that I use Solo Cups in for larger plants. I burnt holes in the bottom of the red solo cups with a soldering iron (time consuming but it works well). I do that to allow for the water to flow thru it. Those are the two sizes that I use. I use floating PVC with plastic netting for mint and watercress.

Permalink Reply by Ned Berndt on August 27, 2013 at 6:57pm

Lisa Johnson,

Interesting about the watercress and mint...could you share some pictures?

Permalink Reply by Pat James on August 31, 2013 at 2:02pm

Went out this morning and bought some blue board. Now I need to figure best spacing. I posted this in another groups so I will do the cut and paste thing and double post instead of typing everything from scratch.

I am replacing several of my old piece of crap styrofoam rafts with Dow blue boards. I also want to change my hole grid pattern and was wondering what is the consensus for the best spacing for an IBC tote? I am currently using 8 inch spacing which gives me room for 21 pots. That is 6 rows with alternating 4 per row and 3 per row. Before I commit and start drilling/burning, I wanted to see what others use.

Permalink Reply by Ned Berndt on September 1, 2013 at 8:16am

Pat,
There is a Canadian firm that supplies ready made rafts with holes spaced for 18 (3 x 6) and 28 (3 x 6) and (2 x 5) staggered...Beaver Plastics. In 2' x 4' size.
Tip - If you're drilling holes for net pots be sure to remove the teeth from the 2" hole saw with a grinding wheel. Basically turn it into hole "knife"...reduces the blue board "dust" significantly