6 Best Greenhouse Temperature Alarms For Frost Warnings to Save Your Plants
Protect your greenhouse from frost with a reliable temperature alarm. We review the 6 best models that send crucial warnings when temperatures drop.
There’s no worse feeling than walking out to your greenhouse after a surprisingly cold night to find your tender seedlings blackened by frost. You did everything right—started the seeds, nurtured them, and gave them a safe home—only to be undone by a few degrees you never saw coming. A simple temperature alarm is the single best piece of insurance you can buy for your plants, turning a potential disaster into a manageable 2 AM trip to turn on the heater.
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Protect Your Plants: Why You Need a Frost Alarm
A greenhouse is a fantastic tool, but it’s not a magic box. It loses heat, and on a clear, still night, it can lose it shockingly fast. The temperature inside can plummet to match the outside air, or even drop below it, creating a perfect frost pocket that will wipe out your tomatoes, peppers, and cucumbers before they ever get a chance.
A simple thermometer on the wall only tells you what happened; it doesn’t warn you about what’s about to happen. A frost alarm is an active guardian. It’s a system that doesn’t just display the temperature but takes action when it hits a critical low point you’ve set. It will send an alert to your phone or sound a loud alarm in your house, giving you the crucial time you need to intervene. This isn’t about fancy tech; it’s about protecting your investment of time, money, and hard work.
SensorPush HT1: Top Pick for Data and Accuracy
If you’re the kind of grower who loves data, the SensorPush is your tool. This small, unassuming sensor is incredibly accurate and tracks both temperature and humidity, giving you a complete picture of your greenhouse environment. It connects via Bluetooth to your phone, where a beautifully designed app displays historical data in detailed graphs.
The real power for frost alerts comes when you add the optional G1 WiFi Gateway. This small hub connects your sensor to the internet, allowing you to get alerts on your phone no matter where you are. The downside is the cost—you have to buy both the sensor and the gateway for remote monitoring. But for those who want to fine-tune their greenhouse conditions and understand trends, the rich data and reliable alerts are worth every penny.
Govee WiFi Thermometer: Best Value Smart Alarm
Govee has made a name for itself in the smart home world, and their WiFi thermometer is a perfect fit for the budget-conscious greenhouse owner. It offers the most important feature—remote temperature alerts sent to your phone—at a fraction of the price of its competitors. It connects directly to your home’s Wi-Fi network, so there’s no need to buy a separate hub.
The setup is simple through their mobile app, where you can set your high and low temperature thresholds for alerts. While it may not have the lab-grade precision or the deep data-export features of a premium system like SensorPush, it absolutely nails the core job. For most hobby farmers who just need a reliable warning when temperatures are dropping, the Govee provides incredible value and peace of mind.
Temp Stick Wi-Fi Sensor: Most Reliable Alerts
When you absolutely cannot afford to miss an alert, the Temp Stick is the answer. This is a serious piece of equipment designed for maximum reliability. It’s built in the USA, connects directly to your Wi-Fi, and runs for over a year on two standard AA batteries. Its entire purpose is to send you an alert when things go wrong, and it does that job flawlessly.
You can customize alerts to be sent via text message, email, or both, and you can add as many recipients as you need. The system will even warn you when the battery is low or the sensor loses its connection. This level of dependability comes at a premium price, making it one of the more expensive options. But if your greenhouse contains irreplaceable plants or the starts for your entire market garden, the Temp Stick’s cost is a small price to pay for its rock-solid performance.
AcuRite 00613: Simple, No-Frills Monitoring
Easily monitor indoor comfort with the AcuRite thermometer and hygrometer. It displays temperature and humidity at a glance, tracking daily highs and lows, and offers versatile mounting options.
Sometimes you don’t need an app or a Wi-Fi connection. You just need a loud beep. The AcuRite 00613 is the classic, old-school solution: a remote sensor for the greenhouse and a digital display for your kitchen counter or nightstand. You set a low-temperature alarm on the display, and if the sensor detects that temperature, the base unit lets out a piercing alarm.
This system’s strength is its simplicity. There are no accounts to create, no passwords to forget, and no reliance on your internet connection. Its major limitation, however, is range. The signal typically works up to 100 feet, which is fine for a backyard greenhouse but won’t work if your structure is further out on your property. For a simple, affordable, and effective local alarm, it’s tough to beat.
YoLink LoRa Sensor for Long-Range Coverage
What if your greenhouse is 500 feet from your house, far beyond the reach of Wi-Fi? This is where YoLink shines. Instead of Wi-Fi or Bluetooth, YoLink uses LoRa (Long Range) technology, a low-power radio signal that can travel a quarter-mile or more. This is a game-changer for anyone with a larger property.
The system requires a small hub connected to your router, but once it’s set up, you can place sensors almost anywhere. The sensors themselves have exceptional battery life, often lasting for years. You get all the modern conveniences—app-based monitoring and alerts sent to your phone—but with the long-range coverage that other technologies can’t provide. If distance is your primary challenge, YoLink is the clear solution.
La Crosse Alerts Mobile: A Trusted Weather Brand
La Crosse has been a trusted name in home weather stations for decades, and their Alerts Mobile system brings that experience to remote monitoring. The system uses a sensor and a gateway that connects to your router, sending temperature and humidity data to the cloud. You can then monitor conditions and receive text or email alerts through their app or website.
The La Crosse system is a solid, middle-of-the-road choice. It’s more robust than some of the entry-level smart home gadgets but not as expensive as the high-end industrial sensors. It’s a great option for someone who wants a reliable system from an established company known for weather-related products. If you already own a La Crosse weather station, their alert system will feel familiar and trustworthy.
Key Features for Your Greenhouse Temperature Alarm
Choosing the right alarm comes down to your specific needs and the layout of your property. There’s no single "best" option, only the best option for you. As you decide, think through these key factors:
- Alert Type: Do you need a loud audible alarm that will wake you from a deep sleep, or is a notification on your phone enough? A system that offers both text messages and emails, like Temp Stick, provides valuable redundancy.
- Connectivity & Range: Is your greenhouse close enough to your house for a simple radio signal (AcuRite) or within reach of your Wi-Fi (Govee)? If it’s out in a field, you’ll need a long-range solution like YoLink. Don’t underestimate this factor. Test your Wi-Fi signal at the greenhouse before you buy.
- Power Source: Battery life is critical. A sensor that dies in the middle of winter is useless. Look for models with long battery life and, ideally, a low-battery warning.
- Data vs. Simplicity: Do you want to analyze temperature charts to optimize your heating strategy (SensorPush), or do you just need a simple "it’s too cold" warning (AcuRite)? Be honest about how much data you’ll actually use. More features aren’t always better if they just add complexity.
Ultimately, any alarm is better than no alarm. The goal is to create a safety net that protects your plants from the one or two nights a year when the weather does something unexpected. Whether you choose a simple $30 audible alarm or a sophisticated Wi-Fi system, you’re making a smart investment to ensure all your hard work in the garden doesn’t vanish overnight.
