10 Tips for Beating the Summer Heat

By: Tawnya Sawyer

Summer is an exciting growing season both inside and out – in the garden and the greenhouse.  The extended light and the rising temperatures bring both benefits and challenges to your aquaponic system. It’s important to note the changes the heat will bring and how it will impact your plants and fish. We have created a list of the top 10 tips to help keep your plants and fish healthy and happy.

10 Tips to Beat the Heat:

  1. Shade for your plants – is very important, especially when they are in direct sunlight. A silver reflective shade cloth will provide the greatest protection, reflecting heat away. If possible, install the shade cloth on the outside of your greenhouse frame to prevent heat gain inside. You can also install on the inside of the greenhouse under the roof trusses, but it will be important to have a ridge vent or ventilation fans that can exhaust the hot air trapped above the shade cloth.
  2. Ventilate your greenhouse – multiple times a day and night. Diseases such as powdery mildew and black mold commonly build up in places where there is high humidity and not enough ventilation. For roll-up side greenhouses, consider installing wire mesh to prevent mice, birds, snakes, raccoons and other predators from entering and eating your crop or attacking your fish. The mesh allows good bugs (lace wings & pollinators) in to help combat the bad bugs.
  3. Aerate your fish tank – to prevent fish from suffering as water temperatures rise. Since hot water doesn’t hold as much oxygen, increasing oxygen and water flow is important during hot weather. This may require added aeration, more water exchange, or other ways to increase surface exchange of air into the water i.e. fountains or bubblers. A green shade cloth is a good option to cover your tanks and protect fish from direct sunlight.
  4. Cover water to reduce algae growth – in tanks, deep water culture troughs, and media beds. Standing water has the potential to grow algae when it is exposed to sunlight.
  5. Make sure to keep water flowing – by having a backup pump, backup aerator, backup power, and/or a backup generator to prevent fish loss in an emergency. Fish can die very quickly due to increased ammonia concentration and oxygen loss during brownouts and power outages.
  6. Be prepared with your pest regiments – aphids, caterpillars, and white flies love hot weather and longer light during the day. Stay ahead of the pests by rotating your pest management methods. Be cautious with any oil based products that are potentially phototoxic (will cause plant burns in hot sun). Spray late in the evening when temperatures are the coolest and be sure to get under the plant as much as possible where bugs like to hide.
  7. Simulate rain in the greenhouse with a hose – simulating rain is a great way to help cool leaves, clean off dust, and debris. It can also help knock off pests that are hanging on to the leaves. Make sure not to do this in direct sunlight or when your light is still on because the water can act as a magnifying glass and burn your leaves.
  8. Transplant after the sun goes down to prevent heat shock – Tiny seedlings are sensitive to many factors. Heat stress poses one of the greatest threats to seedlings. To help them adapt to a new space, plant late into the evening, allowing them to stabilize before the sun comes up. This also works great for cloning and propagation.
  9. Harvest in the dark – for fresh and “crisper” vegetables! Lettuces, kale, chard, mustards, and all other green leafy vegetables take up water and photosynthesizing during the daylight but when the sun goes down, their stem closes locking the water in.
  10. Store seeds and fish feed in a cool dry place – Heat and humidity can significantly damage sensitive seeds and cause fish feed to go rancid. Storing these products in a cool dry place will increase usability throughout the summer.