More Hydroponic Q&A: Humidity, Airflow, Rafts, and Calcium
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We're back with another round of hydroponic Q&A—answers to questions we received last week and a few we asked others ourselves. Quick reminder: nothing here is original to us—we’ve learned all this from other growers and experts along the way.
1. What’s a Good Humidity Target?
We aim to keep humidity low at night and higher during the day. While we don’t run misters to raise humidity, we do run our wet wall, especially early in the spring. This helps:
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Prevent tip burn
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Slow the spread of powdery mildew
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Keep humidity more stable, which helps with all the above
2. Is Vertical Airflow Necessary?
We don’t use vertical airflow in our greenhouse. That said, it can help reduce tip burn, especially if other factors are in check.
📌 If you're experiencing tip burn, check your:
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Nutrient levels
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Humidity swings
Fixing those is more important than airflow alone.
3. Where Do You Get Your Rafts?
We source our rafts from:
👉 BP Grower Supply
4. Does the Air Cone Work in NFT Systems?
Yes! Our AirCone works great in NFT (Nutrient Film Technique) systems.
It offers powerful:
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Aeration
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Cleaning action (especially in gutters and pipes)
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Support against sludge buildup and issues like lithium presence
More dissolved oxygen = better root health and cleaner systems.
5. Do You Carry a Liability Policy?
Yes, we do.
6. How Do You Pop Plants Out of the Plug Tray?
We use a plug popper from Two Bad Cats. It's a wooden tool, and the dowels tend to rot. It works best if you:
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Place an empty tray on the popper
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Then press your full tray on top
This helps align everything and keeps it working smoothly.
7. Do You Disinfect Your Rafts?
Yes—after every harvest.
We built a raft washer that scrubs and bleaches each raft thoroughly.
8. How Much Do You Make Per Square Foot?
Last year, we averaged $1.22 per week per square foot of growing area.
9. What Shade Cloth Do You Use?
We use 55% shade cloth, and yes—it’s automated.
🎥 We also have a video about it if you want to see the setup.
10. How Does Elevated Calcium Help Prevent Powdery Mildew?
Calcium is essential for cell wall strength in plants. When calcium levels are high:
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Leaves become more rigid
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Powdery mildew spores have a harder time penetrating and anchoring
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The plant becomes naturally more resistant
Low calcium = weak leaves → tip burn & easier mildew infection.