Converting the fish tank to a cat proof greenhouse, part 1: starting a cover

I have spent some time thinking about how we can convert our big fish tank into a greenhouse to start seeds in, while also making sure the cats couldn’t jump in.

The original covers the tank came with would have been ideal, but the hinges on those broke long ago.

Since a piece of the filtration system broke during the move, it’s just been sitting in a corner. To keep the cats out, we cut pieces of foam core to fit across the top, then covered the whole thing with a huge table cloth. It turned out to be a great place to store baskets in, and the top became a favorite place for the cats to hang out.

Until they broke through.

We ended up cutting some rigid insulation to fit and taping it in place, which worked much better. With their jumping from the piano onto the top of the tank, though, they’ve knocked even that right off!

What this means is that the cats are used to having access to the top of this tank. If I set it up as a greenhouse to start seeds, they’re just going to jump in, unless I find a way to cover it.

The tank has a bar across the centre and, after thinking about it for a while, I decided to make a pair of wood frames with hardware cloth, that will fit on each side of that centre bar. That way, if I need to get at the seed trays inside, I just need to lift one smaller cover at a time, rather than struggling with one large cover.

I fully expect the cats to jump on while I try to do anything in there!

Today, I got started.

The first thing was to take a tape measure to the inside of each half of the top, as well as the lip the original covers used to sit on. Each side is 16 3/4 inches by 22 3/4 inches. The ends and centre bar have a 1/2 inch lip, while the sides have a 1/4 inch lip.

I then grabbed a couple of pieces of wood I’d salvaged from a shed and started by cutting the long sides. Once I had 4 of them cut, I double checked that they fit properly.

They fit just fine, with a little bit of play that will make putting them in and taking them out easier.

While I was checking the fit, my daughter came by. As we were talking, she reminded me of one of her Christmas gifts to me.

I wish I’d remembered them before I took the measurements! This thing is MUCH easier for me to read than the tiny lines and numbers on my tape measure. It made marking the distance to cut the short pieces a lot easier, too.

Another reason I wish I’d remembered them before I took the measurements.

When I checked the short pieces, they were just a hair too long! The difference is so slight, I could probably sand it to size.

But I shouldn’t need to.

This is how the frame will be laid out. The hardware cloth will be sandwiched between the top and bottom pieces at the corners. I haven’t figure out what I can use to secure the hardware cloth best. Ideally, the wire mesh would be sandwiched between wood all the way around, not just at the corners, but I just don’t have the wood to do that. Nor can I think of anything we have that could be used in a similar way. Whatever I come up with will have to not just support the weight of a cat that’s decided to lie on it, but the force of a cat jumping onto it from the top of the piano. All sorts of ideas some to mind, and get discarded just as quickly. :-/

The thing I’m holding in place in the photo is one of the supports for the light fixture. The L bars insert into ports at the bottom of the light’s frame, so where they are is where the bottom of the light fixture will be.

Once I double checked how everything was going to fit together, I moved on to the next step.

Washing the pieces of wood.

They were probably sitting in the shed I found them in for more than 10 years. My mother tells me that shed was full of lumber when she moved off the farm, some 7 years ago, so what little we found in there was the junk that wasn’t worth stealing, I guess. :-/ Still better than nothing, I suppose. Anyhow. There was a whole lot of grime on them, so I gave the pieces of wood a quick scrub. They don’t need to be really clean. I just need to be able to handle them without getting filthy, and trying to scrub them after the hardware cloth is in place is just not a good idea! 😀

So they are now all laid out in the basement with a fan on them, do dry. I will continue to work on the frames tomorrow!

One of the recommendations for using grow lights to start seeds is to have the lights very close to the soil, and gradually increase the distance as the seedlings grow.

That won’t be an option with this set up.

I’m thinking of lining the inside of the tank with aluminum foil to reflect more light onto the seedlings. It doesn’t need to be from top to bottom; just at seed tray height. Which means I could probably get away with lining all 4 sides with foil in the big tank. I will probably line 3 sides of the 20 gallon tank, too.

The other thing to consider is warmth. We don’t have grow mats, and it’s unlikely we will be able to get any. We do, however, have more pieces of rigid insulation that we can put under the trays, or even along the sides closest to the walls. The LED lights won’t generate heat, but I’m sure we could find some way to warm up the tanks enough for seeds to germinate.

Progress on the set up has, at least, finally begun!

The Re-Farmer

6 thoughts on “Converting the fish tank to a cat proof greenhouse, part 1: starting a cover

  1. Maybe….
    Put the hardware cloth on the floor, put the frame on the hardware cloth, bend the hardware cloth over the frame so it’s folded over onto the wide side of the wood and then staple/nail/screw the hardware cloth in place with as many fasteners as you might need.

    Now you have both the staples/nails/screws and friction holding everything in place. If you really want to secure it, secure the cloth on both sides of the frame.

    It’s possible the cats might not like jumping onto the hardware cloth as their claws kind of fall “in between the cracks”.

    Liked by 2 people

    • I am hoping to be able to use some roofing nail we found a bucket of, but they may be too long. I just have to remember where the bucket is and check. Lol

      I do hope they won’t like the feel of the mesh. It won’t stop them from walking on the frame – they knocked the current cover off and I found them still waking on it, balancing on the top edges! The frame should be okay for that. The light fixture might be a different story, though!!

      Liked by 1 person

  2. Pingback: Converting the fish tank to a cat proof greenhouse, part 2: changed plans | The Re-Farmer

  3. Pingback: Converting the fish tank to a cat proof greenhouse, part 3: covers done! | The Re-Farmer

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