Sep 2020

Mobilize puts custom Growing Degree Day reports in the palm of your hand

Those who are not growers must find that the term “growing degree day” sounds strange. Is it a day? Is it a degree? If you are a grower, you know it’s neither: it’s an index.

For the non-growers among us, here’s the GDD scoop: Like insects, plants develop in stages – such as germination or flowering. The parameters that most affects these developmental stages are air temperature and the accumulation of heat. As the early spring sun warms the air, winter-sleepy plants start to accumulate heat. Some cool season plants like peas or alfalfa don’t need a lot of heat, while others, like corn, need a lot. Unless the plant is stressed by drought or disease, when a specific accumulation has occurred the next stage will be reached. This accumulation is called Growing Degree Days, or GDD. One GDD is one day when the average daily temperature was above the plant’s specific lower threshold, that point below which it is too cold for any development to happen.

Each crop has its own GDD threshold and each stage has its own GDD requirement. Some crops also have an upper threshold, over which either little or no development can happen, so days when the average temperature exceeds the upper threshold must be deducted from the total.

As a grower, you are very aware of the exact GDD for your specific crops. Your granddad might have used his experience and a calendar to decide when it is the right date to plant, apply pesticide, or harvest. He was good at his job and had a few failed crops under his belt, so he usually got a fair idea. But what if the last few months had been quite a bit colder than this time last year? Missing the harvest date by a few days or weeks, no big deal…wait, VERY BIG DEAL. Today’s successful growers must know exactly when to plant, fertilize, deal with pests, and harvest.

It is crucial that you know the GDDs for your specific crop in your specific field, now. And all it takes to know this is a Davis weather station and  a way to get data to WeatherLink, a WeatherLink account, and the Mobilize app on your smartphone.

Mobilize gives you and your team members a truly actionable GDD report, right on your smartphone, any time, from anywhere.

To calculate GDD, Davis’s Mobilize app uses a choice of methods: single sine or integration. Both use the air temperature to assign each day after planting a heat value. The values are accumulated and compared to the target set by the grower. Growers can see exactly when their crop is approaching the GDDs needed for germination or maturity, without even setting foot in the field. Greenhouse growers can use this information to precisely control their crop development.

It is easy to set up your crop in the app. You select the planting date, specific crop type, base threshold, and target GDD. You can choose how the GDD should be accumulated when the maximum threshold is exceeded.

Once set up, you can glance at your smartphone screen and see the percentage of progress toward the target as well as the current GDD. You’ll see the target, the plant date, the GDD for the last 7 days as well as the predicted GDD for the next 7 days. This powerful information gives you the ability to predict not just growth progress, but when herbicides or insecticides should be applied for optimum activity, efficacy, and control. You will have a precise forecast of when root rot or other diseases can develop so you can take effective corrective measures. You will know when to fertilize and irrigate depending on growth stages. And you can accurately compare crop development over different years and locations.

Mobilize offers much more than GDD reports. By combining your own localized weather data from your own Davis weather station and the Mobilize app, you’ll also get decision-driving data and reports on pest management, irrigation, chilling hours, frost, and weather for each of your fields.

Click here to watch a quick walkthrough of the Mobilize app and see how easy it is to set up a custom GDD report.

Scroll Up