Aquaponics - Heat stress

This is a bit of a worry.

It's a 32 degree c day out there and fish tank water is already 30 c. The air temperature in the grow house is 40 c, and we get days of 46 c+ ever now and then.

My first bulk bean experimental planting cup is showing some serious signs of heat stress.

As are the coz lettuce.

The tomatoes on the other hand are loving it, and don't understand what all the fuss is about.

I'm not really sure what to do about it.

I draped some shade cloth over the grow house yesterday, but it actually made it hotter. I think if I leave an air gap it will work, but dark coloured shade cloth touching the grow house roof absorbed a lot of heat.

I think I'll try to add a frame and perhaps a water spray with a temperature probe to start the spray if it gets too hot.

I sprayed some water around and the temperature dropped by around 7 degrees, so I should be able to work something out.


  1. Your beans, lettuces, brassicas (broccoli etc) are cool weather plants.

    There's been work done regarding cooling the water for these types of plants to help with heat stress.

  2. According to the seed packets, in my area my beans are good to plant in spring to late summer, and my coz lettuce, all year round.

    The peas are not supposed to be planted at this time of year, but I have something in mind for them.

    The three different types of bean are all dwarf varieties, so perhaps they behave differently to big ones.

    I chose the dwarf varieties, not because of their planting times, but so my grow house wouldn't get over run. I don't know about such things, so I always just do what the seed packets tell me.


    once I bought two packets of strawberry seeds, and the packet said they would grow. So perhaps seed packet's bend the truth a little to sell a few more than they might otherwise.


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