Hydroponics has recently become a popular buzzword in trendy gardening circles, but it often raises questions for the average gardener – What on earth is it? What does this science mumbo jumbo even mean? What’s wrong with good old soil?
Hydroponics 101 will answer all your questions and provide you with the tools to begin on your own hydroponics journey.
But first, it is important to consider why people choose hydroponics and whether it is the right option for you.
What is hydroponics?
Although it has received a recent bump in the ratings, hydroponics is not a new gardening method. The first evidence of hydroponic cultivation dates back over two thousand years and has advanced leaps and bounds through scientific research in the last century. NASA has even investigated hydroponics as a potential food source for astronauts on Mars.
Hydroponics is essentially about growing plants without soil and providing their nutrients directly through the water. From Greek, it literally translates to ‘working water’; hydro meaning water and ponos meaning labor. Plants typically get their nutrients from the soil, but the idea behind hydroponics is that plants can grow just as well (often even better) when the nutrients are delivered to the roots through their water.
How does it work?
Instead of growing in soil, hydroponic systems use a combination of growing mediums, water, and added nutrients. There are several different types of systems, each with their own pros and cons, but they all make use of this combination. The growing mediums keep the roots oxygenated and helps transfer the nutrients through the roots, often with a pump. Hydroponic growers typically make use of indoor spaces or greenhouses to allow for maximum control of the surrounding environment.
Essentially, hydroponics skips the role of mother nature in growing plants and transfers all the power to you.
The pros
This may seem to require a lot more time and effort than your average weekend gardener tends to devote, but there are many benefits making the process worthwhile.
- Plants grow faster. If you have an impatient streak, hydroponics is your answer. Plants tend to grow at least 20% faster in hydroponic systems compared to plants grown in soil under the same conditions. The energy usually used by the plant in gathering nutrients from the soil gets put into growth instead and the controlled environment allows for each plant to be under near-perfect conditions for optimal growth.
- No soil. This on its own comes with a number of benefits. People with poor garden soil or without gardens at all can grow almost anything indoors without worrying about poor growth rates or bad conditions. Without soil, problems with weeds are eliminated and there is no concern for soil-related diseases or pests. Soil conditions can also be difficult to control, and your garden soil is not guaranteed to work for all the plants you want to grow. The potential problems with soil gardening are non-existent with hydroponic systems.
- Water-saving. Saving water become a serious concern in recent years. The rise in temperatures and increasing droughts spell trouble for high water consumption gardens, but this concern can be eliminated with hydroponics. Hydroponic systems are sealed to prevent evaporation and no water is lost to the surrounding soil. Any run-off water can be recirculated back into the system to ensure nothing is wasted. In terms of agriculture, hydroponic farming uses only 10% of the water soil agriculture does, making it the ideal method for farming in water-scarce areas.
- Space-saving. The root systems in soil gardens need to travel farther to get the nutrients they need, compared to hydroponically grown plants that get their nutrients directly. With more compact roots, plants can be grown closer together, which is a great benefit for those who need to garden completely indoors.
The cons
All the amazing benefits must have convinced you already, but in case you are still on the fence here are a few cons to consider.
- Expenses. There are a few start-up costs for a hydroponic garden to set up an efficient system, including pumps, filters, growing media, and nutrients. Although there are more initial expenses, once you get the hang of hydroponics there is less risk as you have a greater chance of successful growth with a controlled environment. Money spent on equipment is ultimately money saved on dead plants in the garden.
- System failure. Ah, the dreaded load shedding. Not only is it a risk to our Sunday night movies, but for hydroponic gardeners, it also becomes a risk to the plants. If the system is switched off for extended periods of time the plants lose their only source of survival and begin to die. If you live in an area with an unstable power supply and no backup, you risk losing your plants completely.
- Expertise. Hydroponics takes knowledge and a bit of practice to get right, just like any method of gardening. However, this series will provide you with everything you need to know to get started and your experiences will give you the rest of the knowledge to become an absolute pro.
Getting Started
Systems
There are many types of hydroponic systems with their own variations and pros and cons. In systems that need growing mediums, some easily available options are Coco Peat, Perlite, or Rockwool, each with their own benefits suitable for individual needs. All hydroponic systems function on the same principle and only differ in how the water, nutrients, and oxygen are delivered to the plants. Your choices will depend on space, cost, time, and the kind of plants you plan on growing. The four most common system are –
- Wick Systems: This is generally considered to be the easiest system to set up and manage; a reservoir of water and nutrients is covered by a container holding the growing medium and plants. A wick transfers the water carrying the nutrients to the roots through the growing medium. While this is the simplest system on this list, it may not work with larger plants that need a lot of water as the wick cannot transfer the water fast enough. Try herbs or microgreens and avoid lettuce using this system.
- Deep Water Culture: Deep Water Culture is a similar set up to the wick system, but instead of the growing medium the plants are placed on a floating styrofoam platform, so the roots are submerged in the water. Oxygen is delivered to the roots through a water pump. This system is great for short-lived water-hungry plants as the roots are in direct contact with the water but may not work for plants like tomatoes with a longer lifespan.
- Ebb and Flow: This is a more complex option but gives you the chance to optimize the system for the best growth of your plants. A timer and pump are used to periodically pull water up from the reservoir to the growing medium which then drains out back into the reservoir. The use of a timer allows you to adjust the watering schedule for different variables like temperature or humidity, or to grow plants in separate pots and make adjustments for each one.
- Nutrient Film Technique (NFT): The more complex NFT systems use a nutrient pump instead of a timer to continuously pump nutrients directly into the water without a growing medium. The grow tray is placed at an angle so the nutrients can pass through the roots and back into the reservoir when they reach the end of the tray.
Get your lab coat on
Now that the system is set up its science time!
Macronutrients
Plants, like people, need a wide range of nutrients that serve different functions to keep the plant healthy. Luckily, most stores selling hydroponics equipment do the work for you and sell nutrient packages, but it is always good to know what is involved – once you get the hang of it you can try mixing your own. Make sure the nutrients are specifically designed to be dissolved in a hydroponic system and avoid using normal garden fertilizers as they are designed for soil.
Macronutrients are the most important for plant growth and include Nitrogen (N) for the leaves, Phosphorus (P) for photosynthesis, Potassium (K), Calcium (Ca), Magnesium (Mg) and Sulphur (S). Micronutrients are required in fewer amounts but are still important for growth, including Zinc (Z), Manganese (Mn), Iron (Fe), and Boron (B).
Water
The mineral content and pH of the water can change the effectiveness of the system so controlling these factors is vital. It is best to filter your water before introducing it into the system as ‘hard’ water with high mineral content, like tap water, can prevent the nutrients from properly dissolving. The water pH should be slightly acidic (between 5.8 and 6.2) but chemicals can be used to adjust the pH if it is out of this range.
Lighting
Since most plants grown in hydroponic systems are not meant to be grown indoors, you may need a grow light to ensure optimal growth. Most hydroponic kits from stores come with a grow light but if you are building your own system you will need to invest in one. Bulbs with more orange or red light are best as they stimulate growth, like an HPS (High-Pressure Sodium) bulb. The lights need to be on a timer to ensure the plants get the right amount of light; a minimum of 6 hours up to 12 or 16 hours a day.
Room Conditions
Controlling every aspect of growth includes the room conditions. These few factors need to be considered –
- Temperature. Summer vegetables should be grown in temperatures from 15° to 26°C. Winter vegetables like lettuce and spinach should be grown between 10° and 20°C.
- Humidity. The ideal humidity range is 40% to 60% as anything higher can lead to bacterial problems. A humidifier may be necessary to manage anything out of this range.
- Air flow. The more CO2 plants get, the faster they grow so a room with good air flow is a must.
Which plants to grow
Some beginner-friendly plants to grow are:
- Leafy vegetables like lettuce, spinach or kale
- Herbs like parsley, basil, mint or coriander
- Tomatoes
- Strawberries
- Peppers
What not to grow if you’re just starting out:
- Vegetables with deep roots like carrots or potatoes as the roots need more depth and may need to be supported.
- Large vegetables like pumpkins or corn as they take up a lot of space and need adequate support.
Although veggies are the most popular plant to grow hydroponically, other fun options include flowers, catnip, chamomile, and lavender.
Getting to set up, know and operate your hydroponic garden may seem difficult, but it is important to remember that the end goal – a system that largely manages itself and produces perfectly grown plants – is well worth the effort!
Hydroponic system DIY
The price of some hydroponic systems can be a deterrent for many people, but you don’t need a fancy set up to start on your hydroponics journey. With a few supplies and one free afternoon, you can have your own deep-water culture hydroponic system at a fraction of the price.
You need
- 41l Plastic tub (dark in colour to prevent algae growth)
- 8 x 80mm plastic net pots
- Aquarium pump and air stone
- 1m 5mm tubing to fit pump
- 2 x control valves
- Tri-pack nutrients
- pH test kit
- pH down
- A growing medium of your choice
- Vegetable seedlings
Step 1
Start by cutting 8 holes in the lid of your plastic tub for the net pots to fit through using a 78mm hole saw. At the same time, drill a small hole in the side of the tub close to the lid to fit the pump tubing through.
Step 2
Using one of the net pots as a guide, fill the tub with water until it covers about 20mm over the bottom of the pot.
Step 3
Test the pH of your water using the pH test kit and adjust it if necessary, using the dry pH down.
Top Tip: If you are planning on sticking with hydroponics long term, it may be easier to invest in a pH and EC (electrical conductivity) meter to better control the environment your plants are grown in. A pH meter is used to measure the pH of the water which should be slightly acidic, and an EC meter is used to measure the strength of nutrient formulas, or you could get a combo meter with both readers in one. These meters can be costly, but they can quickly tell you if there is a problem with your system that allows for easy adjustments and foolproof growing. They are also useful if you plan on having more than one system with different types of plants, as the pH and nutrient levels can be managed to suit each individual plant’s requirements.
Step 4
Connect the control valve to the tubing and attach both sides to the pump and air stone through the drilled hole in the side of the tub. Place the air stone at the bottom of the tub and switch the pump on.
Step 5
Using the instructions on your tri-pack nutrients according to the plants you have chosen, add the nutrients to the water and close the lid.
Step 6
Place your chosen plants in the net pots and surround the roots with your growing medium of choice. Add your pots to the holes and place the tub under a grow light or in an area with high sunlight.
