Hydroponic farming, or water culture, is the indoor cultivation of food without the use of soil, relying on only water, oxygen, nutrient-dense solutions, and, of course, light. Hydroponic plants grow in a soil-free, liquid medium, where the water flows through roots to deliver nutrients that are readily absorbed in the presence of light. The light, whether natural or artificial, helps the crops grow them faster and bigger than they would in soil.
This method is truly a masterful combination of science and art. While scientists may reject my use of the word “art” in this context, creative skills and imagination combined with the scientific know-how will take you an extra mile further when cultivating in water than traditional farming methods would.
🤔 Why hydroponics? What are the benefits?
Hydroponic farming is a fantastic option for folks living in conditions unfavourable for conventional farming, allowing them to keep growing food of their choice in confined spaces — such as a basement or garage — where direct sunlight is limited. You can even harvest superior food over a longer period during which you cannot leave home, such as complete lockdowns during the COVID-19 pandemic. Whatever the indoor conditions are, they can be exploited to grow microgreens, salads, herbs, and leafy greens including some fruits, like strawberries and blueberries.
Hydroponics is an excellent opportunity to become self-sufficient in food production for communities living in the condos, studio apartments, and yard-free houses, making them less dependent on their everyday visit to the grocery store. Besides self-reliance and sustainability, hydroponic crops don’t have the carcinogenic effects of pesticides, fertilizers, and herbicides that interfere with human immunity, reproduction, and nervous systems. Hydroponically produced microgreens, salads, and herbs can be part of your life if you are eager to know how to grow them!
Hydroponics, with all its added benefits, can bring nature back to your home if you want to realize the wisdom of sustainability through fresh air and natural greens. If you are interested in the best practices for grow hydroponically — along with its pros and cons — this article may be fully advantageous for you, as my priority is to grow everything you need to grow organically.
What are the different types of hydroponic systems?
This may surprise you, but there isn’t just one type of hydroponic farming. In fact, there are six key variants of water-based systems. While all plant roots require water, nutrients, and oxygen to flourish, hydroponic systems are designed with the ultimate objective of feeding roots with these core essentials.
Each system has its own set of benefits and drawbacks. That said, however, deep water culture (DWC) is best for the beginners because they are easy to set up and offer growers a variety of microgreens, salads, herbs, and vegetables to choose from. Ultimately, urban farmers can choose any of these systems depending on their ease and availability of the space indoors — as well as their enthusiasm for a more challenging system. There is an option for every home garden!
💧 Nutrient film technique (NFT)
NFT systems — not to be confused with non-fungible tokens — are popular among home growers. It involves nutrient-rich water continuously flowing through plant roots and then proceeding to the reservoir. This system is ideal for growing microgreens, salads, herbs, and vegetables that mature early.
💧 Deep water culture (DWC)
DWC is easy to build and operate. A majority of home growers like it because the plant roots are submerged in a nutrient solution, while oxygen is provided through an air pump to the plants resting in the growth medium.
💧 Wick system
It’s the simplest system where plants are hanged above the reservoir containing nutrients solution while the roots absorb the necessary moisture from the suspended growing media. An air pump is not needed but can be installed for better growth.
💧 Ebb and flow (aka flood and drain)
This technique involves the periodic flow of nutrient solutions to plant roots, with the solution pushed to the drain while the system rests. The ebb and flow system requires some expertise to handle, namely to evaluate and analyze moisture levels in plant roots.
💧 Drip irrigation
Droplets of nutrient-rich water are dripped directly onto the roots of the plants, and a timer can be used to regulate the frequency of the droplets.
💧 Aeroponics
Aeroponics use the minimum amount of water to grow plants, made possible by a water mist that adds moisture to the growing plants with plenty of oxygen. These systems are a bit expensive and, again, require expertise to operate.
What crops can I grow using hydroponics?
Although there is a comprehensive list of vegetables, salad greens, herbs, microgreens, and fruits that you can grow in water culture, it is recommended that prioritize your crops according to your domestic needs.
- Vegetables. Frequently grown vegetables include peppers; tomatoes and cherry tomatoes; cucumbers; peas; broccoli; radishes; cabbages; and cauliflower.
- Salads. Popular salad greens for hydroponic systems include spinach; lettuce; broccoli; various beans; kale; cilantro; asparagus; radishes; and spring onions.
- Herbs. Common herbs include basil; mint; chives; marijuana; oregano; cilantro; garlic; and spring onions.
- Microgreens. Your hydroponic system can help you up your salad game with microgreens including wheatgrass; oat and barley grasses; chicory; dill; fennel; cauliflower; cabbage; celery; turnip; radishes; broccoli; garlic; onion; and leek.
- Fruits. Strawberries and blueberries are commonly grown in water, too.
Artificial light in hydroponic culture
As previously discussed, all plants need water, oxygen, and nutrients to grow, but food assimilation takes place in the presence of light.
Photosynthesis can only occur in the presence of light, which converts into chemical energy in the form of carbohydrates and sugars — the building blocks of any plant. Plants need about six to eight hours of daylight to carry out these processes. If the grow room is located far from the direct sunlight, the plants will require the help of artificial light to supplement sunlight. Here’s everything you need to know about acquiring artificial light for your water culture project.
🔆 What is the wavelength of light needed?
Generally, plants grow vigorously in the presence of light wavelengths ranging from 400 to 700 nm. This will cover all the entire energy requirements during different stages of growth.
The precise light spectrum, intensity, and duration work together to boost vegetative growth, flowering, and reproduction cycles. The cool blue wavelengths, between 430 and 450 nm, are needed during initial stages of growth including seedling development and vegetative growth. Red wavelengths, between 640 and 680 nm, are required for flowering, fruit formation, and maturity.
The biggest advantage of artificial grow lights is the ability to increase the duration, thereby accelerating the growth process — which, of course, isn’t possible when you’re relying on old Mr. Sun!
💡 What type of grow light should I use for my indoor farm?
Any grow light that adopts 10 W double chip LED technology can help plants grow. The wattage may be variable, but any light ranging between 400 W to 1000 W can be used from the seeding to the maturity of hydroponic plants.
Manufacturers often adopt aluminum sinks to dissipate heat, which prevents the crops from burning. The lights with optional vegetative and bloom switches are preferred, along with their capacity to keep both switches on, simultaneously.
⏳ How long should I use lights for? Does it vary between on growth stages?
Any full-spectrum light needs to be kept on for 14-18 hours a day during the germination and seeding stages, placed 24″ to 36″ away from the foliage. This distance is further reduced during the vegetative stage (between 20″ and 26″) and the final flowering stage (12″ to 20″). The light’s working duration is also reduced to 12 to 14 hours during the vegetative stage and 9 to 12 hours for the flowering stage.
Most LED lights come with the user’s manual along with the distances chart. Moreover, most companies hold free services and offer replacement warranty between two and five years. It’s best to read the fine print before proceeding with such purchases.
Factors affecting plant growth in hydroponic culture
Many factors interfere with plant growth in any hydroponic systems when not acclimatized under the crop requirements, however, the humidity and temperature in the grow room, pH of the nutrient’s solution, EC, TDS, and PPM of the nutrient solution play a vital role in the overall growth of the plants.
🌡 Humidity and temperature control
Humidity and temperature affect many progressions of the cultivation process, including germination, growth, and flowering time. Temperature requirements vary in different plants, according to their discrete development stages. High humidity, on the other hand, is a hindrance to nutrient uptake and promotes diseases in the grow room.
A comprehensive knowledge of humidity and temperature requirements of a plant determines their growth success and the quality of harvest. Placing the humidity and temperature gauges inside any growing environment and monitoring them periodically will help control both of these factors. With these gauges, you have total control over the microclimate and can grow your foodstuff successfully, regardless of the outdoor environment. This maximizes your yield potential and increases income if growing commercially.
⚖️ pH Control
pH values indicate the acidity or alkalinity of the nutrient solution. Any value ranging between 5.5 to 6.5 is considered the best for the absorption of nutrients. Slight variations on both ends affect absorption by the roots suspended in the solution.
To monitor any variations, pH meter is mandatory, especially after adding new nutrients to the solution. pH can also be tested with Litmus paper or an electrometer with speed and reliability. You can also correct levels using pH up and pH down solutions, which are available online.
🧪 EC, TDS, and PPM
You might be wondering what on earth all these letters mean. Hydroponic nutrients often consist of phosphates and nitrates that raise the electrical conductivity (EC) of the water. The exact measurement of EC determines the concentration of such nutrients in the water, which can be corrected by adding or avoiding certain substances.
On the other hand, total dissolved solids (TDS) determines the overall amount of dissolved minerals that indicate the quality of the solution. The higher the TDS and parts per million (PPM) of any liquid, the lesser the absorption of nutrients by the roots. Handheld EC and TDS meters give you instant results, while you can correct both after selecting the proper nutrients for any solution according to the need of growing plants.
You may be a bit confused initially, but once you pick up the right techniques and a system that’s best for you, you will be boss of your own hydroponic farm!
Updated August 9, 2021. Originally published April 19, 2020.
