Jon Greene
As the Senior Technical Specialist for Bluelab's US/Canada team, Jon is passionate about the art of growing, and enjoys sharing his many years of knowledge and experience with growers. In his spare time, he enjoys hiking, bike riding, boating and other outdoor activities.
Hydroponics is a growing method that doesn’t require soil. Instead, your plant root systems are supported by a soil-less medium while having access to a steady supply of nutrient-rich water.
There are many benefits to growing hydroponically. Without the need for fertile land, this growing method allows you to produce food anywhere in the world and at anytime of the year. Not only that, but you’ll be able to achieve this with fewer resources; it’s estimated that hydroponics uses up to 95% less water compared to traditional open-field agriculture.
In addition, when you grow your plants in a hydroponic system, their growth rate is estimated to be 30-50% faster than a soil-grown plant in similar conditions. That’s because, in hydroponics, your plants spend less time growing their root system in search of food and more time growing upward and producing fruit.
Take a look below to discover our top seven tips for managing a successful hydroponic growing operation. With these tips, you’ll be able to achieve optimal plant health and high yields with every single grow.
Know your water
Since there’s no soil in hydroponics, which acts as a natural buffer, it’s important to ensure that you’re using the purest water available. If you’re using your own source water, it’s beneficial to check its composition by paying for a laboratory analysis.
Poor water quality can cause a range of toxicity and deficiency issues in a hydroponic system, especially at the beginning of your plants’ lifecycles or later in production. In fact, if you’re using municipal water, this could contain elements like calcium, magnesium bicarbonates, chloride and sulfates, which will also affect the pH (potential Hydrogen) and EC/PPM of your nutrient solution. Municipalities may add these elements to make water suitable for humans, but that doesn’t mean that it will work well for your plants.
The more you know about the composition of your water, the better you can manage or treat it to make it suitable for your plants.
Read more: Why is water quality important?
Balanced nutrients
When it comes to feeding your plants, make sure that you’re well acquainted with the nutrients you’ve decided to use.
The most important thing is to stick to the nutrient manufacturer’s recommended dosage. Adding more than this may affect the health of your plants. In addition, you should add the recommended dosage in small amounts, allowing the nutrients to fully mix into the reservoir before adding more. If you dump in the full dosage in one go, there’s a risk that some essential elements could precipitate out of the solution, thereby becoming unavailable to your plants.
It’s also crucial that you take note of the nutrient scale that your nutrient manufacturer is using. Set your EC meter to the same scale so that you always get accurate readings.
Lastly, if you do decide to mix different nutrient brands when feeding your plants, make sure that you calculate your doses carefully to avoid over- or underfeeding your plants.
Optimal pH
When it comes to the fundamental parameters of plant health, pH is one of the most critical measurements to keep track of. That’s because pH is life, and all plants have a preferred pH range where nutrients will be most readily available to the plants’ root systems.
As mentioned above, soil acts as a natural buffer to help maintain a steady EC and pH; while you still need to check pH in soil, you won’t need to check it as often as you would in a hydroponic system. For soil-less growing media, it’s crucial that you regularly check pH and adjust levels when necessary.
When lowering your pH with acid, it’s always better to use a lower-strength acid and add small amounts regularly as opposed to using a stronger acid, which could cause you to quickly overshoot your pH target. If you’ve already bought a stronger acid, you can dilute it before using it to adjust pH.
Plentiful oxygen availability
Oxygen is vital for optimal plant health. In nature, when plants photosynthesise, they draw in oxygen through their leaves at the top and through their roots at the bottom. In hydroponics, we’re creating an artificial environment, so we need to add in the oxygen to the plants' root systems.
In hydroponics, plants need to get oxygen from the water being used to provide nutrients. This is enabled through the use of air pumps, air stones, bubblers or an air gap (as seen in an NFT setup).
Additionally, the temperature of your water affects oxygen availability. As a general rule, warmer water holds less oxygen, while cooler water holds more. You should aim to keep your reservoir water within a temperature range of 18-22 °C (65-72 °F).
Some hydroponic growers add hydrogen peroxide to increase oxygen in their water, but it’s important to note that this may result in providing oxygen in a way that’s inaccessible to the plant.
Consider your environmental factors
Environmental factors can have a big impact on plant health. They are also linked to each other, where if one isn’t working correctly, it can have a knock-on effect on other environmental factors.
Take lighting as an example. The atmosphere inside your grow room is just as important as the grow light that you end up choosing. While plants can still grow by having an inadequate light source but the proper atmosphere, a high-quality light without the proper atmosphere will not lead to plant growth.
Temperature is also important for the healthy development of the plant. Younger plants – with a developing root system - tend to prefer higher temperatures, allowing them to absorb more moisture in the air through the stomata in the leaves. When you maintain a good temperature range, this can also reduce the risk of mould and mildew buildup. Try to ensure that your temperature doesn’t fluctuate too much between day and night cycles.
Relative Humidity (RH) measures how much moisture is in the air at a given temperature, compared to how much moisture the air could potentially hold at that temperature. If your RH is too low, your plants may take up too many nutrients because of the lack of moisture available to be taken through their leaf stomata. This could lead to nutrient burn, where your leaves look wilted with scorched edges. On the other hand, if your RH is too high, mould and mildew can prevail.
Ventilation can be used to increase or reduce humidity. Ventilation is another factor to consider; when plants transpire, they release excess water. Without adequate ventilation, this excess water has nowhere to go, which means that the growing environment may be susceptible to mould. Similarly, you should always water your plants when the lights are on so that they can help evaporate any excess water.
If you’re using LED or MH/HPS grow lights in your hydroponic setup, CO2 supplementation should help to increase yields. By adding CO2 to a room with intense lights, this allows your plants to use more of that light, thereby increasing photosynthesis. However, keep in mind that CO2 is heavier than air, so consider using oscillating fans to distribute the CO2 evenly throughout your grow room. You should also turn off your CO2 supplementation at night when your plants are no longer photosynthesising.
C2H – Clean, calibrate, hydrate
There are many factors involved in growing healthy plants, but your meter’s probes are the heart and soul of the feeding process. If your EC is too high, you can burn the plants; too low and the plant will not get the nutrients they need to grow.
Your probes should be cleaned regularly. In a commercial facility, you should aim to clean your probes once a week and, if you’re a hobbyist, it should be no less than once a month.
In addition, you should keep your pH probes hydrated in KCl whenever they’re not in use. If your pH probe is submerged in a monitoring system, then keep the probe hydrated in its cap between water changes and reservoir cleanings. You should never hydrate a pH probe in RO (reverse osmosis) water, as the low ionic content will deplete and shorten your probe’s lifespan.
It’s important to calibrate your pH probe at least once a month or whenever you’re cleaning or changing it out. Like a battery, a pH probe will eventually slow down and need to be replaced. Think of it like this: your pH probe is using a little bit of its life every time we take a measurement, but keeping it clean, calibrated and hydrated will help it last much longer.
Your team
Our last tip is all about your growing crew. If you’re managing a hydroponic setup as part of a team, it’s essential that you communicate clearly about procedures and changes, so that everyone’s on the same page.
Even when your setup is kitted out with the state-of-the-art machinery currently available, things can and will go wrong. That’s why you and your team need to know your equipment and how it works. Practice and communicate – then you’ll be prepared for any situation that comes up.
If you follow these seven pro tips, you’ll be well on your way to managing a hydroponic system that really works, producing high-quality produce and boosted crop yields.
Have we missed any of your top hydroponic tips? Let us know in the comments below.
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