Whether you’re after a new lockdown hobby or you’re getting more serious about sustainable living, hydroponics is the answer! It sounds daunting, doesn’t it? That’s what this beginner’s guide is for! A quick Google search for a grow kit might have you umming and ahhing, wondering where to look. It all looks a bit complicated at first, you might be thinking it’ll be expensive to set up or that you need all sorts of snazzy equipment.
The great thing about hydroponics is that your setup can be as simple or sophisticated as you like! You can throw together a Drip Irrigation or Recirculation system as a hobbyist for around £60-90, but if you’re after the works (including a grow tent) you could be looking at upwards of £400.
Hydroponics is the method of growing plants without soil. Plants thrive on the nutrient solution alone. The growing medium merely acts as a support for the plants and their root systems and helps to hold moisture around the roots.
No soil means there are no weeds or soil-borne pests or disease. Plants will be able to achieve the optimum nutrient and moisture levels in the hydroponic system. This has several advantages: healthier plants, faster-growing plants, and more resistant plants as they will not become stressed through lack of water or nutrition. The root systems will stay smaller in hydroponically grown plants; the plant will concentrate on developing plant mass and the desired fruit or flower, this can result in 30% faster growth.
This will also enable the grower to have more plants in a given area. Hydroponically grown plants never get root bound, so will rarely need repotting. As hydroponics is clean, it can easily be used indoors or in a spare room as well as a greenhouse or conservatory.
1) Deep Water Culture (DWC) – perhaps the most popular method on this list. It involves the suspension of plants in aerated water. The plants, housed by net pots, submerge their roots in the oxygen-rich nutrient solution which provides a continuous flow of water, oxygen and nutrition. Many people consider these hydroponics in their purest form.
2) Ebb and Flow (Flood and Drain) – popular with home gardeners, this method involves the placement of plants within a spacious growth bed filled with growing medium. This is then flooded with a nutrient-rich solution, sitting a couple of inches beneath the top layer to prevent overflow.
3) Wick – possibly the simplest of the lot, this is a passive system (meaning zero mechanical parts) in which plants are nestled in growing media on a tray which is sat atop a reservoir that houses a water solution containing dissolved nutrients. Wicks (often made of rope, string or felt) travel from the reservoir to the growing tray. Nutrients and water flow up the wick and saturate the growing media around the plants’ root systems.
4) Drip – a system for the more adventurous among you which can be altered for different plant types and be as big or as small as you like. Nutrient solutions are controlled through their injection directly into the plant’s base; a drip emitter controls the amount of solution allowed to travel. You can also adjust the flow to meet the needs of specific plants.
5) Aeroponic – easier to understand than build, the hint is in the name. A system that has your plants suspended in the air while mist nozzles beneath them spray nutrients directly into the root. This ensures the plant’s needs are met and can be cost-effective as the unabsorbed mist is caught within the reservoir below for reuse.
6) Nutrient Film Technique (NFT) – not to be confused with non-fungible tokens, this easily scalable system suspends plants above a continuously flowing reservoir of a nutrient solution that washes over the ends of the plant’s root systems whilst ensuring limited wastage. Unlike DWC systems, an NFT system doesn’t immerse the roots of plants in water, with the stream (or ‘film’) only flowing over the ends of the roots. The roots’ tips wick moisture up into the plant, giving the exposed root system all the oxygen it needs. The bottoms of the channels are grooved, meaning the shallow film can pass over the root tips with ease.
Without soil, materials are needed to transmit the aforementioned nutrients, oxygen and moisture to the plants’ roots in addition to holding the plants themselves. As for the most commonly used growing media in Hydroponics…
Coco/Coir - its airy, light nature promotes root growth. Its lack of nutritional content gives you complete control over what your plant is actually getting. While you've got to keep an eye on your nutrient pH, the wider margin for error in comparison to soil makes coco an ideal starting point.
Soil Mixes – your go-to if you’d rather not have to test pH. These are also difficult to over-fertilise, but in turn, require more work and care not to over-water.
Clay Pebbles/Granules/LECA (light expanded clay aggregate) – beloved by Dutch bucket users, this lightweight hydroponic substrate with units the size of peanuts is often used in both hydroponic and aquaponic systems. Its high pore space means few blockages and better percolation. While it can be costly, it’s reusable and environmentally friendly.
Perlite – a heat expanded, a man-made product that is perfect for use as a hydroponic growing medium. Perlite retains enough moisture for it to be suitable as a hand watered medium, but also has sufficient drainage to be used in a recycling drip irrigation system. Perlite is extremely lightweight and is suitable for use in a variety of growing containers e.g. pots, trays etc. It also has sufficient water absorbency for it to be used in bottom-fed auto watering systems.
Vermiculite – despite having favourable moisture and nutrient retention capability, it has poor drainage capacity which is why it’s often used in combination with perlite. This is something you probably don’t want to hear about an already expensive product.
Bat Mix/Guano & Worm Castings – Bat manure is naturally rich in phosphorus and potassium, guaranteeing abundant growth. Bat-mix contains sufficient nutrients to meet all the needs of the plant throughout the complete cycle. Worm castings are also popular with organic growers as they can be used at any time during the growth cycle; they boost the nitrogen levels in soil, promoting vigorous plant growth. You can use worm castings to refresh used soil, mixing between 10% and 20% by volume to reinvigorate the soil with essential elements and minerals. Worm castings can also be made into a tea which can be fed to plants and helps integrate beneficial bacteria into your substrate.
COGR/Rockwool/Coco Slabs – versatile and acceptable as a standalone material in many hydroponics systems, particularly recirculating ones. Their predominantly vertical fibre structures promote rapid rooting and vigorous vegetative growth.
Plants, much like children, need nurturing and a push in the right direction to reach their full potential. Nutrients are the answer to bringing the best yields. A nutrient solution is a hydroponic equivalent to fertilizing soil.
In essence, a hydroponic nutrient solution is a liquid comprised of the necessary nutrients required for plant roots to come into contact with and maximise growth. The keyword here is ‘necessary;’ different plants require different nutrients.
Not only that but there are other factors to account for, like growth cycles and the weather to name two. This is why there are different formulas and combinations for hydroponics.
That might sound daunting, but the fact is that major nutrients for plants stay the same a lot of the time, just with different percentages! The table below should help break this down further…
Macronutrients…or macros, are what plants require in large amounts:
(N)itrogen – the primary food for growth in plants, particularly in the vegetative growth phase. Without nitrogen, you get no leaves; it plays a key role in leaf and stems growth as well as a plant’s colour and size. it also has a vital role in chlorophyll, amino acid, protein and co-enzyme synthesis.
(P)hosphorus – vital for photosynthesis and one of the components of DNA, the plant’s genetic memory unit which is involved in plant vigour and seed production. Phosphorus is required in large amounts during the early phase of seedling, flowering stage and germination; it’s responsible for forming roots, seeds, flowering and fruits.
(K) Potassium – okay, that one doesn’t work, but that doesn’t make potassium any less important. In fact, it plays a role in all stages of plant growth; aiding in the synthesization of sugar, starches and carbohydrates. It also plays a role in a plant’s resistance to insects and bacteria as well as chipping in on the development of roots, stems and flowers.
(Mg) Magnesium – now onto your secondary macros. Fast-growing plants require magnesium in large amounts; it’s essential to chlorophyll production and helps create oxygen through photosynthesis. It’s recognizable in healthy and vigorous plants.
(Ca)lcium – another one needed in large amounts by fast-growing flowers and vegetables. In fact, it’s almost as vital as the primary macros as it’s necessary for cell formation and development.
(S)ulfur – Sulfur is a structural component of 2/21 amino acids that create protein. It also helps activate and form certain enzymes and vitamins, including vitamin B.
(Bo)ron – used in conjunction with calcium in synthesizing the functions and structure of cell membranes; boron also aids with seed production and pollination.
(Mn) – Manganese, coupled with iron, aids in nitrogen utilization during chlorophyll production.
(Fe) Iron – required for chlorophyll synthesis; it’s also important to the enzyme system.
(Zn) Zinc – works with other elements to form chlorophyll; it’s important for stem growth and is a vital catalyst for most plant enzymes.
While this doesn’t cover all the micronutrients pictured above, providing you become acquainted with your macronutrients and keep the micronutrients listed in check you should be fine.
You’re probably wondering why I left this until now. It’s not a secret that plants need water to grow, but something you might not consider is the quality of the water you’re giving them. Water quality can play a big part in how well your plants will grow. Tap water, for example, can contain unwanted minerals or have an undesirable pH level. For optimal results, choose fresh rainwater (easy to come by for those of you in the UK) or bottled spring water.
Speaking of pH levels, pH is a very important factor in plant care, perhaps more so in hydroponic systems as your plants will be submerged more often than not. Because of this, you’re going to want to stay within your plants’ pH range.
The chart above shows the vital plant nutrients covered above and the pH levels to which plants can take said nutrients. Different pH levels cater to different plants but the sweet to shoot for is between 5.5 to 6.5. pH testing kits can help you keep an eye on these levels, while pH-Up/pH-Down can be added to your water reservoir to maintain the perfect pH for your plant.
Your nutrient solution is one of the most important additions to your repertoire, therefore you must invest in a high-quality solution that suits the plants you’re growing. Mixing your own is always an option, but as you’re just starting out, Pro XL and Advanced Nutrients are always a good shout!
As a rule, plants should get at least 6 hours of sunlight per day; space for your plants to get ample sunlight may be tough to come by when indoor gardening, but that’s where grow lights come into play. Advancements in technology have led to artificial light becoming a much more viable option for growing, bringing about results that rival natural light!
When you’re new to hydroponic gardening, your best bet is to start off with clones rather than growing from seeds. If you choose the live plant/seedling route, make sure you take the time to rinse the soil from your plant’s roots to avoid the contamination of your water and nutrient solution.
By now you probably know what type of system you want to get started with, now it’s time to get your kit together and get growing!
Putting together an indoor hydroponic system is a lot simpler than you probably thought, right? Now you know your basic systems, you can probably already picture ways in which to make your ideas more advanced and what pieces you’d want to add next. Hydroponic gardening is for pretty much anyone who wants to give it a go, all you have to do is make sure your plant’s roots get adequate water, nutrients and oxygen in the absence of soil. With what you’ve learnt here, you should be more than ready to put together a hydroponic system you can call your own.