When it comes to gardening, considering soil temperature is crucial but often overlooked. Usually, the species or varieties of species that end up in our beautiful gardens evolved and are acclimated to its weather conditions. Nonetheless, they are susceptible to temperature and to the chemical and biological factors that depend on them.
When you are keeping the garden for pleasure knowing this type of information is handy and if you are a data-driven person it will be fun. In the case you’re gardening to produce crops or flowers that will become part of your diet or income, this will be fundamental and might be something you want to start doing as soon as possible if you haven’t started already.
Measuring the soil’s temperature is not a complicated task, most gardens will need few sensors if not just one. You can choose whether you want to use an analog or digital sensor, check the soil temperature by hand, or set up an automatic sensor. Here is our top 10 list of products that will come in handy in your garden’s soil temperature sensing journey.
Plants are not the only affected organisms when it comes to soil temperature. Meso-, microfauna, and microorganisms that live in the soil are directly affected by its temperature, they are the ones that keep the soil healthy and alive. If you are looking forward to nourishing your garden’s soil to maximize its capacity, you should also pay attention to its temperature. A simple analog thermometer is a great tool to have around, not only is it inexpensive,
it does not require a setup and it is quite sturdy to keep up with the dirt and water that will inevitably go in contact. You can leave it in the soil and have several around the backyard in case you need to keep constant monitoring.
A digital solution that’s accessible and easy to use. This will be a good companion while monitoring the soil temperature of your garden, you can move around and collect data quickly after the press of one single button.
This soil thermometer includes an electrical conductivity (EC) sensor, this will allow you to have two simultaneous measurements. Soil temperature is a relevant factor but its relation to other physical soil parameters is not always linear, this said you might want to keep track of other variables that define the suitability of your soil to nourish and maintain your plants in good shape.
Following our previous idea, soil EC is not the only soil parameter you might be considering keeping in mind. Soil humidity is a major variable to consider, it is related to soil temperature but also to soil health. A soil that is able to keep its moisture is usually alive and in good condition unless it's because it is highly compacted and becomes flooded. In either case, if you decide to monitor your soil temperature, why not add other variables?
This option allows one to determine a value for total dissolved solids, this last value is more useful in hydroponic systems, so if you also have a hydroponic garden consider this option as it will become useful for both your in-soil and hydroponic gardens.
In this day and age digitalization is common and new levels of complexity are made available and made simple for our use. Great news! With this sensor, you can collect your soil’s temperature measurements wirelessly on your cell phone or computer. If you want to monitor your soil constantly but don’t feel so comfortable with the idea of going every time to find your thermometers and keeping the data in a notebook then this is an option to consider.
A rugged and sturdy option that offers high technological ease for data recovery. As with the previous product, the Hobo sensor connects wirelessly to your mobile device and allows you to collect data under an easy configuration that you can set up with its software. Time series are no problem with this sensor and you can have as many as you need, the price can be limiting in this product but if you have a large and productive garden it might be worth considering.
In a more complex operation, you might want to set up sensors at multiple pots or garden zones, keep constant monitoring, store the data in digital media and use it for generating statistics and figures. This is helpful when you want to understand trends or if you have very delicate plants that will suffer from any change in temperature. You can connect these sensors to an Arduino board (see next item) in order to gather all the data you will need.
Arduino systems can get complex, but you can fit them to your specific needs. This is a great project if you want to learn or if you already know how to program. This item doesn’t do much alone, you can use this board to log your sensor data. This board is a great solution but it’s recommended for someone with some expertise in the Arduino world as it can be a great challenge to know all the pieces you need to get the best out of your temperature sensors. In case you are curious about the Arduino environment and want to learn how to program such systems to gather data from your garden, you will definitely enjoy an Arduino starter kit. This option welcomes you into the world of programming and robotics, with a good set of materials and explanations you will be off to a good start in your DIY garden monitoring.
Soil temperature tests are good as part of our garden keeping but it is true that they can become challenging, not of complexity in the measurement since most systems offer a straightforward way to gather the data, but because the soil can be very hard due to drought, rocky material or dense roots and plant material. In those cases, you want to avoid pushing your thermometer too strongly into the soil,
because it might break it and also because this kind of work can be physically demanding. A soil sampler can make a huge difference when it comes to measuring soil temperature, there’s a varied set of options of different sizes so you can choose the one that fits your needs.
The seed and seedling stage is the most sensitive stage of the plant life cycle to soil temperature Lewandrowski et al, 2021. At that point, the plant is completely dependent on the soil. It is helpful to measure the temperature before you sow the seeds or transplant seedlings into the soil. You could be wondering if the previous devices are also suited for your seedling germination beds. They sure are, but there are also devices designed specifically for this purpose.
As mentioned above, the seed and seedling stage is the most sensitive of soil parameters. You work in favor of your seedlings' development when you grow them first in a tray where you can control conditions with more detail. Using a soil temperature sensor connected to a heating mat will help you control such conditions even better.
In case you’re going the extra mile making your own compost you will want to check its temperature, too. Temperature is a definitive factor for microbial reproduction and your compost's proper functioning depends on it. Converting the organic matter back to soil requires a healthy and constant growth of the community of microbes and tiny insects which, in the majority, are very sensitive to temperature.
Compost is a crucial input for maintaining your garden’s soil and plant health, if you are producing your own compost in large quantities and even more, if you’re using the thermophilic composting method, you should think about getting a very large thermometer in order to keep your compost at just the right temperature as it goes through every step of its cycle.
How many sensors do you need? You can answer this question by analyzing how often you add changes to your garden, how many rare plants you have, at which rate you transplant seedlings, the weather variability condition in your region, and the size of your garden. One thermometer in a huge garden with many plants to pay attention to can be time-consuming and physically demanding.
A Quick Summary
Soil temperature is crucial for plant development, the early stages of plant life are the most delicate and responsive to soil factors. There are plenty of options to monitor your garden’s soil temperature, from cheap and simple to complex and specialized. It is up to you to determine which is the best strategy according to your needs, but in general, a hobbyist garden doesn’t require many sensors or elaborate instruments. Monitoring soil temperature can benefit anyone interested in gardening, no matter if you are keeping a garden for mindfulness or if you’re running a small business it will provide you with valuable information about your plants, soil, and compost health.