This Week's Focus in the Greenhouse
Week 24 has been all about pepper plant care and heat management. With a major heat wave and high humidity hitting Iowa, the team has been focused on keeping conditions stable across the main greenhouse, both isolation rooms, and the two hoop houses outside.
No big transplants or system changes this week, just the disciplined, detail-oriented work that keeps a pepper crop healthy when the weather doesn't cooperate.
Aji Charapita pepper plants thriving in the Dutch Bucket system inside Isolation Room 1. These plants are looking great heading into the heat wave.
Seed Stock Production
Our seed stock plants are the heart of what we do at Pepper Joe's, the Dragon's Breath and other pepper varieties we grow specifically to produce the seeds that end up in your hands. This week, with a major heat wave hitting Iowa, protecting these plants has been our top priority. Here's what the team has been doing to keep them healthy and on track.
Heat Wave Management: What We're Doing and Why
Fan Setup and Airflow
One of our first moves during a heat wave is getting fans positioned throughout the greenhouse. They serve two purposes.
First, airflow. Our greenhouse uses a wet wall system to cool incoming air, but that cooler air needs to move through the entire space to be effective. Fans help distribute it evenly so plants across the greenhouse benefit, not just the ones closest to the wet wall.
Second, stem development. We intentionally direct fans to blow on the pepper plants. This mimics natural wind, which signals the plant to build a stronger, thicker base stem. It's a simple technique that pays off later in the season when the plants are loaded with fruit and need that structural support.
Fan setup inside the greenhouse during the heat wave. The black fans on the ground move cool air from the wet wall across the entire greenhouse. The blue fans on the flood tables blow directly onto the plants to mimic wind and build stronger base stems.
Fertilizer Tank: Catching Bacteria Early
This one is worth talking about in detail because it's easy to miss and the consequences can be serious.
Warm temperatures create ideal conditions for bacterial growth in fertilizer tanks. Our team caught signs of possible bacteria early, which is exactly what you want. The response was straightforward: empty the tank, clean it thoroughly, and add Ecofoil insulation around the outside to help regulate the tank temperature going forward.
Why does this matter?
Bacteria in your nutrient solution can contribute to root rot, which moves fast and can cause significant damage before you even see symptoms above the soil line. Catching it early, before it reaches the root zone, is the difference between a minor maintenance task and a major crop problem.
If you're running a hydroponic system at home, keep an eye on your reservoir during hot stretches. Cloudy water, unusual smell, or slime buildup are all signs to act on immediately.
The fertilizer tank emptied and cleaned after the team spotted signs of possible bacteria growth, a risk during extreme heat. Ecofoil insulation has been added around the outside of the tank to help regulate temperature and prevent future bacterial growth.
Hoop Houses: Keeping Plants Watered and Cool
The hoop houses present a different challenge. They get significantly hotter than the main greenhouse, and the plants inside need more frequent attention during a heat wave. The team has been focused on consistent watering and monitoring to keep stress levels down.
Inside one of our hoop houses, plants are in the raised beds with drip hoses running along each row to keep up with increased watering demands during the heat wave.
Why Heat Above 90 Degrees Is a Problem for Peppers
Peppers are heat-loving plants, but there's a threshold. Once temperatures push above 90 degrees, a few things can go wrong:
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Pollen viability drops
- High heat damages pollen, which means poor fruit set even if the plant is flowering normally.
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Soil dries out faster
- More frequent watering is needed to keep the root zone from drying out between cycles.
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Blossom drop
- Plants under heat stress will drop flowers before they can set fruit. It's the plant protecting itself, but it costs you yield.
We're monitoring all plants closely, inside and outside, and making adjustments as needed. The goal is to keep stress to a minimum and protect the crop through the heat.
Looking Ahead
- Continue heat wave monitoring across all growing areas
- Track blossom set on transplanted plants post-heat stress
- Monitor fertilizer tank post-cleaning and confirm bacteria-free before resuming normal feeding schedule
- Grow Bags arrived, so likely will get the rest of the grower plants transplanted into the bags
What This Means for Home Growers
If you're growing peppers outside right now and dealing with the same heat, here's what to prioritize:
- Water more frequently, morning is best so plants have moisture going into the hottest part of the day
- Add mulch around the base to slow soil moisture loss
- If you're seeing blossom drop, don't panic, it's a stress response. Keep conditions stable and the plant will resume setting fruit when temps moderate
- Check any reservoir or water storage containers for signs of bacterial growth
A few resources worth bookmarking:
- Pepper Plant Care Guide: From Seed to Harvest
- Top Super Hot Pepper Growing Mistakes and How to Avoid Them
- Full Library: Grow With Joe
Keep Up with the Greenhouse
Missed last week? Week 23: Dragon's Breath in the Dutch Buckets
Want to see how the season started? Start at Week 1
Stay spicy. Thank you for being the best pepper community around.
🌶️ The Pepper Joe's Growing Team