Thursday, October 28, 2010

Mini-greenhouses or coldframes - not sure what to call them

First post in a while. I've been so busy with work and travel that I haven't had any time to spend in the garden. Maybe that's why it's been so sucky lately??


Dedicated readers (if there are any) may remember that last year, I put together a makeshift, greenhouse-like structure out of old fencing, some fenceposts, and some plastic tarps. Rather than go down that same path this year, I decided to build a mini-greenhouse for each of my grow tubs.

 First, I built a wooden frame around the grow bed. Not as easy as it sounds, even though all the grow beds are the same product. They each seem to sag in a different way, so each of the frames had slightly different dimensions and different heights.

Next, I created a PVC greenhouse using mostly existing 1/2" PVC that I had from other experiments uses. I bought special 45 degree elbows and special 3-way fittings for the bottom corners from a greenhouse supply store.

Once the PVC frames were done, I used my old plastic that I used last year. I basically rolled the frame in the plastic, then used plastic clips to hold the clear/opaque plastic to the PVC frame. Each greenhouse has 2 little chimneys that I'm hoping will help it from getting too hot in there. Though the plastic drapes down the sides, it's certainly not air tight, so there should be some air flow, even when the sides are fully down.

 Here's a view through all 3 greenhouses. I rolled up the sides to keep air moving through there. I probably will keep it rolled up until it gets closer to 25 degrees at night. 

The cilantro, arugula, and spinach that I've planted, along with the tub full of strawberry plants, proved last year that they can handle the cold. The greenhouses should help warm things up during the day nicely, and they'll keep the frost off of the plants at night. Another side benefit is that they keep the leaves from landing on the grow beds! This time of year, it's a daily chore picking the leaves out.

I put in another order for rainbow trout this year. It went so well last year, I figured we'd do it again this year!


ChiTown_Hydro said...

Very cool blog Brian. I am doing a very similar project myself, except in extra space in my apartment. I have experimented with NFT hydroponics 2 years ago, but after reading about the ease of maintaining aquaponics, and the fact you do not have to change entire water reservoir every two weeks, I am converting my old system to an aquaponic system. Love your blog nice work

Adam Maxey Sleeper said...

Hey Brian, my name is Adam. I am in the process of building small scale, homemade AQ system myself. I am having some trouble finding a small enough, dry pump (as in not submersible). I came across your blog with a Bing search, so you got any tips on providers. My system is small, about 40-45 gal tank for fish and 2 8 gal plant grow beds. I am using a bell siphon controlled ebb and flow design for the beds. So, just curious is you had any tips about pump suppliers.

Brian Naess said...

Adam,first, why do you want to use a non-submersible pump? If you're worried about sucking up some gravel or other such media, then you could consider adding another 30-50 gallon sump tank that could just be a plastic bucket or tub. A submersible pump (which are very easy to find from aquarium stores, hydroponic stores, or even places like Lowe's) could be placed in the sump. An additional benefit is that you can rig up something like a CHOPS system (constant height, one pump) which would be wise, given your small tank size. You don't want the water level in the fish tank to get too low (while it's flowing through the grow beds).

Second, remember that you want to have as close to a 1:1 ratio of grow bed volume to fish tank volume. Having only 2 8 gallon grow beds will likely not be enough to filter your 40-45 gallon fish tank. Of course, a lot depends on how many fish you put in your fish tank.

Hope that helps.


Lisa said...

Brian...I have an AP system in Holly Springs (ebb and flow) and am building a raft system for next spring...a couple of questions and do you heat your water through the winter and if so how...what fish do you keep (it seems you cycle into trout but what from)...and what are you feeding them...for comments...i have found a tilapia supplier in SC that is reasonable and sells both female and male fingerlings (currently have them in an aquarium)...let me know if you are interested in further info...tim (lisa is the wife)

Brian Naess said...

I don't heat the water in the winter. Our location is practically ideal for a year-round, two species rotation. You would have trout in there over the winter (December to early April), and then put tilapia in there from April through mid-October.

The water is very cold, but the plants (spinach, arugula, cilantro) seem to be able to handle it. Granted, they don't grow all that quickly this time of the year, but they manage.

If you have a greenhouse, it would be cool in the winter to have an outdoor pond/tank for trout, then pump that water into the greenhouse, where you could have a small heating tank to warm up the water to 50 degrees or so before you put it into your growbeds. I think the winter species would really thrive in those conditions.

As it is for me, the plants manage, the fish do OK, and then things pick up in March, when it starts to warm up a bit.

As it turns out, I didn't get trout this year. I couldn't find a supplier anywhere near, and I didn't feel like paying for hundreds of miles of shipping or driving 4 hours+ to pick them up, each way.

Instead, I got some catfish fingerlings and threw them in. Hopefully, they'll be able to hang in there during this cold spell!

I found a good fish supplier (for everything other than trout): southeast pond stocking

Lisa said...

I checked out the fish web-site looks good ( i used fosters in the past)...btw i have channel cats in with hybrid bluegills and they are toughing it out (water temp around 40 even in the green house) they have been in the system since late april and there are some big swings in growth rates fish to fish...let me know if you want to meet up next time you are in the Holly Springs area...tim

Brian Naess said...

How can I get ahold of you? Send me an email to brian [at] briannaess [dot] com.

I'd like to see your system some day - probably some time after the holidays.


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