how to: setup a greenhouse covering for your pond

Living in a temperate climate means water temperatures are not conducive to Koi growth on a year round basis. In Toronto this typically means fish stop eating in early November and likely don't begin eating again until mid April

I highly recommend heating, but it is not for everyone. Constructing a greenhouse however, is an easy 1 - 2 hour job, is inexpensive and provides a huge benefit to your fish

Key Benefits of a Pond Greenhouse

You can expect to begin feeding a couple weeks earlier than normal as well as feeding your Koi later into the Fall with a greenhouse. In fact, here in Toronto, most clients have had no ice on there ponds whatsoever with just a greenhouse covering and bubbler

If you put your greenhouse up early enough, it will stop any leaves from getting into the pond. Additionally, your koi are visible throughout the Winter instead of being under ice. This is key if there are any koi health concerns

pond cover Materials List

  • 1.25 inch gray electrical conduit - for hoops - comes in 10 ft. lengths, this is the best diametre because it is strong but still flexible. Place 3-4 feet apart. For ponds 5-6 feet wide, 1" conduit can be used

  • 0.75 inch gray electrical conduit - for cross support, 10 ft. lengths, affix to the 1.25" conduit with duct tape at the top peak of the hoops

  • 0.75 inch hollow metal rod - come in 10 ft. lengths, cut in half and used to anchor hoops

  • Rebar - 8 foot - cut into half, to anchor 0.75 cross support conduit

  • Super6 6 mil. greenhouse poly - do not use vapor barrier or utility plastic, it has no UV resistance. 1 solid piece needs to used or it will be blown apart by the wind

  • At least 2 people - although it can be done, it is difficult going solo

  • Post Pounder - to easily drive in the metal rods without damaging them like you would with a sledgehammer

  • Ladder / Plank - for larger structures, you will need to go out over the pond to tape the cross support conduit to the hoops

  • Duct Tape - to tape 3/4" cross support to the 1 1/4" hoops


The overall design concept is one of flexibility and slope. This alllows the cover to move with high winds and snow and rain to run off