Home / FAQ
Hydroponics is the process of growing plants using only water. They may or may not have a growing medium which provides the roots with protection and support. The growing medium is usually inert and offers no nutrition to the plants. Instead of soil to supply food, nutrients are diluted into the water in which the plant roots are immersed. This method allows the water and nutrients to enter the roots more efficiently and leads to faster growth and higher yield.
Not at all! -- As with almost anything it can be as simple or as complicated as you want it to be but there is nothing inherently complicated about hydroponic growing. It can even be as simple as a container full of water and an aquarium pump!
Without soil, weeds have nowhere to pop up, and it is much harder for soil-borne pests like insects and bacteria to grow and thrive. Soil also slows the absorption of nutrients down as the roots have to actively seek it out through the soil. With hydroponics, the nutrients are absorbed more efficiently by the roots of plants. Easier uptake by the plant results in much faster growth and higher yield.
Hydroponics also allows correcting nutrient deficiencies much more responsive. Simply add the deficient nutrients and they are immediately absorbed by the plant to address the deficiency. Traditional soil gardening can take much longer for the nutrients to reach the roots.
Plants grown hydroponically can result in 30% faster growth since both water and nutrients are both readily available at all times. This is becoming a preferred medium by many, especially for indoor or greenhouse grow setups.
Soil is much easier to contaminate and tends to be messy. With hydroponics, it is possible to keep the entire grow room sterile, and is useful for preventing all kinds of contamination that just simply would not be possible in soil grown environments.
Anything can be grown hydroponically, but some species make more sense than others and the technique can vary according to the species.
Herbs, tomatoes, peppers, hot chilis, lettuce, chard, cucumbers, broccoli, beans, snow peas, flowering plants, orchids, banana, and tobacco, as well as other tropical plants and fruits, are easy to grow. Even in the UK!
Root crops like carrots or potatoes are much harder to grow hydroponically (though not impossible).
Widespread pesticide use among food crops has led to concerns over healthy eating and food sourcing. In fact, recent reports suggest that up to a third of all store bought vegetables contained pesticide residues. Even food labeled organic are not completely free from pesticide use. Around 70% of organic produce sold in the UK are imported from overseas, often from countries with much lower food safety standards than the UK has.
With hydroponics, it is easy to avoid pesticide use with proper precautions, and there are organic fertilizer options available. With hydroponics, you can grow your own food and know exactly what has or has not been done to it so you can have peace of mind with what you’re eating. This can be done year round and is fairly easy to produce a steady supply of organically grown fruits and vegetables to feed you and your family.
Overseas there are a number of 'hydro-organic' growers who produce and sell high-quality produce, some of which have received organic certification. In the UK, organic and hydroponic growers have historically viewed each other with suspicion and the two growing methods were at one time thought to be incompatible. Even now some UK organic bodies take this view. However, more and more growers, and more importantly, the public, are beginning to realise that as long as the produce is fresh, pesticide free and healthy it makes little sense to stick to this outdated position. With full spectrum organic nutrients now available, such as Earth Juice and others, hydro-organics is now a reality, with an ever-growing number of converts.
In much the same way as traditional gardening, hydroponics can be as cheap or expensive as you want it to be. You can build your own from materials found at a hardware store for less than 40p. You can also choose to purchase more specialised equipment from hydro shops.
We sell all the poly tubing, pumps, and containers to get you started on building your own hydroponic setup as well as pre-fabricated professional growing systems suitable for both beginner and experienced growers.
For those looking for larger, more automated systems we supply high-tech items such as atmospheric controllers, nutrient micro-dosers, grow tents, and ventilation systems. The cost can seem high at the beginning for these items but quickly pays off with the high yields that can result even from minimal effort.
Once your system is up and running, the annual costs of nutrients and pH controls needed to cultivate 90 kilos (200 Lbs) of tomatoes is roughly between 38p and 50p! That many tomatoes would normally cost around 480p from the supermarket.
This large margin is not limited to tomatoes. Other herbs and veggies produce similar savings.
Yes! There is roughly a 30% yield increase on most hydroponic crops compared to soil-grown. This, of course, can vary a bit depending on the crop species and the chosen growing methods.
Hydroponic crops have much better access to the nutrients they need. As a result, they are able to thrive and grow very happily. The plant's food source, sugar will be in strong supply and the plant will be able to express the best flavour possible. Healthy plants always taste better and hydroponics has a tendency of producing very healthy plants.
Some crops such as hot chilis and citric fruits can even have the flavour controlled by moderating nutrient levels and the pH (acidity) of the water. Citric fruits can be made sweeter or more sour a with some simple modulations in the nutrients, and hot chilis can be made hotter or milder in a similar way. It’s fun to experiment with this!
Hydroponically grown plants have a lower incidence of pests but are not immune. There are precautions that can be taken, such as keeping outdoor gardening tools away from the indoor grow setup, wearing gloves, and cleaning your tools after use.
In the event that a pest makes its way onto your plants, there are a variety of natural pesticide options that are completely safe to use on food products. Pyrethrum and neem, for example, are highly effective and are both derived from edible plant sources. Pyrethrum is extracted from chrysanthemum plants which are actually used medicinally for headache sufferers.
For organic gardeners, there are also organic pesticide options available such as predatory insects.
For mold growth, there are a variety of safe and natural treatments as well. Some only require a change in environmental control, while others can be wiped out easily with beneficial bacteria that are found in sprays such as this.
These organic pesticides are highly effective in smaller scale grows but are more expensive in comparison to the much harsher commercial pesticides. This is why some large growers still choose to use harsh and toxic chemicals despite the existence of effective natural products.
This is a very interesting method of pest control. It involves applying additional insects to the crop that are known to attack the problem pest. Depending on what is attacking your crop depends on the best predatory insect option. This solution generally takes a while longer to control the pest, and will never completely eradicate them as it would lead to their destruction as well. Rather, it will result in a balance between the predator and pest as is found in natural environments. This will keep the pest controlled and prevent it from destroying your crop. All without the use of pesticides!
The best growing mediums can vary depending on the application, crop choice, and experience of the grower.
For beginners, rockwool makes a great choice because it is easy to work with, and provides a buffer for moisture control in the event of a pump failure. Its ability to absorb water prevents the roots from drying out as quickly which can be fatal for the plant. Rockwool will even maintain the suggested 60/40 water to air ratio which will greatly help the health of the crop and takes out a lot of guesswork. You can even germinate seeds, or make clones using rock wool which makes it a perfect medium for beginners to experiment with. A lot of professional growers continue to choose rock wool as a growing medium as well.
Another great medium for beginners and experts alike is hydroton. These are made from LECA clay which makes them inert and light. This medium can be cleaned between crops and re-used but is also affordable for those wishing to minimize contamination risk even further by replacing the medium after each harvest. It is suitable for most hydroponic applications aside from NFT and aeroponics.
Coco coir is another great option that resembles soil but still provides the benefits of hydroponics. It is a great medium for organic growing and is best used with a drip system or hand watering. Do not use recirculating systems for coco coir as this can clog pumps and significantly increases chances for contamination.
Perlite and vermiculite are other options but are much less popular among hydroponic growers. The smaller particle size of these mediums can lead to pump blockages, and are harder to work with. They make great top dressings and are great for hand watering setups as they hold moisture in very well and are cheap to purchase.
The last medium is actually no medium. This means the roots are directly immersed in the water without anything to hold the roots. This is a popular choice among expert growers as it can lead to further increased yields but are highly susceptible to pump failures and environmental shock. NFT and aeroponics are the best applications for this style of growing.
We recommend beginners avoid this technique until some of the other variables such as water cycles, temperature, and humidity are worked out and understood first.
There are so many different hydroponic techniques out there it can be intimidating for beginners. The truth is that they all work and we suggest if something stands out to you to just jump right in. The concepts are more or less the same for all of them and there are plenty of resources available online for each method.
That said, deep water culture or drip systems are the simplest by design. NFT and aeroponics, on the other hand, tend to be more touchy and can be difficult to get the hang of at first.
Opinions can vary on this, but generally, an 18 on and 6 off is recommended. Some prefer to run the lights 24 hours a day but this is not suitable for all crops.
Some species depend on changes in light cycles to begin flowering. By changing the cycle to 12 on and 12 off, the plants will begin sending out flowers which then develop into those tasty fruits.
Generally once a week is recommended for reservoir changes for optimal growth and the highest yields. This can be stretched to a 2-week maximum, however. After this, you risk nutrient deficiencies and contaminations in the water and root zone.
These are two common growing methods that are intended to produce the highest yield possible.
SOG stands for sea of green. This is because it places a lot of smaller plants together with very little space in between. This technique offers an even distribution of light across the canopy (top of the plants) and wastes very little space. It does make it hard to get to the plants near the center of the group and allows pests to spread quickly between plants so extra care is needed to catch pest problems early.
SCROG is similar to SOG but uses a screen placed above the plants which are then weaved through the screen (purchased here) as they grow. This helps to provide an even distribution of light across the canopy as well and makes efficient use of space. In an effective SCROG, there is almost no light reaching the bottom of the plants as the maximum amount of leaf coverage above catches the light first. This technique also provides the fruit with added support while it begins to grow and become heavy.
Aquaponics is a symbiotic combination of fish and hydroponically grown plants. It is a cycle where fish excrement is pumped into the growing medium to be used as fertilizer. The plants then filter the water to be dumped back into the fish pond below. The only thing added to a functioning aquaponics setup is food for the fish. This is a popular organic growing method that uses the same principles as other hydroponic principles. The fish can either be pets such as Koi or goldfish, or food such as tilapia. There are large scale aquaponics farms across the world and it is likely to be a common method of food production in the future.
What lights do I use for indoor growing?
There are a few great options for growing crops indoors and each has its own benefits.
Compact fluorescent (CFL) lights are a popular choice for beginners because they are cheap to buy, energy efficient, and highly effective. Not just any CFL can be used, however, as plants require a specific spectrum to grow effectively. There are a variety of CFLs available that are designed to emit the best spectrum possible for plant growth such as this.
High-pressure sodium (HPS) lighting is one of the gold standards for more advanced indoor gardeners and emits an incredible amount of light energy for plants to soak up use to towards growth. These lights are more expensive than CFLs and emit more heat which will need to be vented off so as not to cook the plants to death. They also require additional ballasts to run the lights but overall can significantly increase yields. HPS lighting is the best option for the flowering stage of growth.
Metal Halide (MH) is another great option and is very similar to HPS. It also requires an external ballast to run and produces a significant amount of light energy and heat. This type of bulb is better for the vegetative growth stage.
LEDs are also available and are likely going to be the lights of the future. They are significantly more expensive up front but have incredible life expectancies and low energy consumption. Some boast only a 20% reduction in efficiency even after 25 years of constant use! This makes them a great investment for long term growing. Due to the lower energy requirements, they also emit much less heat, which makes them a great option for smaller spaces or places without adequate ventilation. LEDs come in different light spectrums based on the findings of the manufacturer's research. This is an area that is quickly evolving and new discoveries are made each year.
Clones are genetically identical copies of a plant. Unlike insects and animals, plants can grow differentiated cells from anywhere. This means they can begin growing roots from a stem if it decides it will be beneficial to its survival. To make clones, the plant stem is cut at a node ( an area where leaves or branches meet on the stem) and placed in water or rock wool medium. After just 1-2 weeks roots will begin to grow out the bottom and a new plant is born. This new plant is genetically identical to the plant it was removed from and interestingly is considered to be the same age genetically. Clones are an important part of hydroponic cultivation.
pH is an expression of the acidity or alkalinity of something. The lower the number is, the more acidic it is. 7 is considered neutral.
pH will affect what nutrients the plants can absorb into their roots, so it is important that it is kept within a suitable range. If pH drops too low or too high, nutrients will not be able to enter the plant's roots and deficiencies will occur. This will eventually lead to the death of the plant if it is not corrected.
5.5-5.8 is the range in which plants will absorb all essential nutrients in a hydroponic setup. Keeping it around 5.6 will have the best results and allows a bit of a buffer on both sides. The pH will vary as the nutrients are used up and metabolites are released into the water so make sure to check this every day or 2 to ensure it stays within this range.
For soil, the pH of the water should be between 6.2 and 6.8.
Depending on where you live the tap water can vary in pH. In the UK the water can vary significantly between 6 and 9.5 depending on where you live. You can change the pH by adding either an acid to bring it down, or an alkaline to bring it up. Only very small amounts of these substances are needed to change the pH so be careful when starting out. Purchasing an electronic pH tester can save you tons of time and effort and ensure your pH is as near to perfection as possible. There are cheaper options available such as litmus test strips. These work fine but are not as accurate and can become fairly time-consuming.
With hydroponics, water is much more conserved than traditional gardening methods. This is because it is usually a closed loop where the water is reused over and over again for about a week. Different plants species drink varying quantities of water throughout the week, and temperature will affect how much water is lost through evaporation. In an average setup at a temperature of around 25 degrees C, a 100L reservoir is more than enough water to maintain a 1m squared flood table for a week including water loss. Systems such as drip or NFT often require even less.
Yes. As long as your tap water is clean you can use it for hydroponic culture. In some places where tap water is considered hard water, there might be up to 400 ppm of solutes already present in the water, and the pH could be as high as 8. This simply means extra care is needed to ensure the ppm does not become too high when adding nutrients and it will mean more pH corrections will be needed in order to achieve optimal pH levels.
Using filters such as reverse osmosis can bring the water closer to 0 ppm and a pH of 7.
Reverse osmosis is a special type of filter that uses pressure to force water across the salt gradient which yields up to 99% pure water. This is extremely clean and considered the best for hydroponic growing. The downside is that RO systems can be expensive, slow, and waste ⅓ to ½ the water that runs through them.
See Extraction calculator.
PPM stands for parts per million. This is a measurement of the amount of solids dissolved in the water. It is a useful diagnostic tool for assessing certain growth issues and helps to identify the maximize amount of nutrients you can feed your plants. Generally, the recommended ppm is between 500 and 1000.
Both synthetic, and organic nutrients are available for hydroponic cultures. Synthetic nutrients (mineral salts) are generally cheaper and offer a greater yield. They also provide a lower risk of contamination and help to maintain a more sterile growing environment. Synthetic fertilizers are simply mineral salts which are converted in the plant to other chemicals. They are very safe for food crops and have been used by commercial growers for decades.
Organic fertilizers can be made from ingredients such as bat guano, fish emulsion, bone meal, or blood meal. They tend to have a much stronger smell but are thought to increase the flavour of some crops, especially those that produce terpenes or other volatile oils. Organic fertilizers are usually more expensive and have a greater risk of contamination.
The NPK ratio refers to the amount of Nitrogen (N) compared to phosphorous (P) and potassium (K). Different species of plants and different life stages of plants demand certain macronutrients over others. Generally speaking, nitrogen is needed for the upward growth of the plants and is needed in the highest amounts during the vegetative growth cycle. Phosphorous is mainly needed for the production of roots and flowers and is needed in the highest amounts during the flowering stage. Potassium is needed for the immune system of the plant and adds general strength and vitality throughout the life cycle of the plant. Its needs are fairly consistent in both vegetative and flowering cycles.
These ratios tend to confuse people, and our advice for beginners is not to worry too much about these ratios in the beginning. Plants have their own ability to decide how much of each nutrient it requires at different stages of its life, and will thrive well in hydroponics regardless (as long as enough fertilizer is given of course). Nutrients offering different ratios simply make this more efficient for the plant and can increase yield by offering a boost of one or 2 particular nutrients during specific stages of development. If a plant does not need as much phosphorous during the vegetative cycle, for example, the ratio can shit to include less phosphorous and more nitrogen. This allows the greatest efficiency of the nutrients delivered to the roots and allows for the maximum ppm of each nutrient. Using well formulated NPK ratios can increase yields.
When choosing to grow with soil, we do not recommend using soil from your backyard. This is because the soil in your backyard is part of a larger balanced ecosystem. Every square centimeter of garden soil si home to thousands of organisms. These organisms are kept in check by the other variables of the environment including insects, bacteria, fungi, wind, rain, and even animals like birds. When you remove this from the environment and place it in a warm, humid closed environment like a grow room, whatever is living in that section of soil will multiply and begin to grow out of control. This is what we call contamination and can be hard to correct, especially if the contamination involves a root fungus or a plant virus. Contamination is very common from garden soil and can end up being a lot more trouble than it's worth.
Soil is cheap, and it will save you a lot of headaches if you purchase quality, pasteurized or sterilized soil from garden centers or grow supply shops. Try this one.
For those of you with a grow room or grow tent who have the ability to control the environment for your plants. This can be an incredible tool for minimizing pests and maximizing yields. But what temperature is the right temperature? As with most things in hydroponics, this can vary a bit between plant species. The general range, however, is around 20-30 C. In some cases, a cooler temperature can be beneficial such as with cloud forest orchids. A good idea is to consider the crop you are growing and investigating what its natural habitat might look like. Is it a tropical, temperate, or desert growing species? Try to simulate these natural environments through temperature and humidity as much as possible, and don't be afraid to experiment a little bit with your crop in order to find its optimal range.
Depending on the location, size, and light selection there are a few variables with maintaining your temperature. Here in the UK where we have milder temperatures throughout the year it is easier to control the temperature with ventilation and rarely will an air conditioner be necessary. Having ventilation is important for your plants to get adequate carbon dioxide, but also keeps the air cooler. By venting the warm air produced by the lights out, cooler air is brought in and the temperature can be effectively controlled with fan speed. If you find it's getting too hot simply increase the ventilation fan speed. If it is dropping too low, slow it down instead.
In the summer months when it can get quite hot, your fan may not be enough to keep these temperatures at optimum ranges, if this is the case, a great option is to cool the water temperature. It is the temperature at the root zone that will have the largest effect on the plant's health. You can buy water chillers for larger setups, or simply toss a frozen water bottle into your reservoir when you need to cool it down. The last option is using an air conditioner. This is only really recommended for larger setups and can be quite expensive in both startup cost and on the electricity bill. These are generally not needed in places like the UK however.
The ultimate solution to your temperature control is to purchase an environmental controller such as this. Connect all of your devices into this unit including your vent fan, intake fan (if you have one), water chiller, and air conditioner and it will use these to keep the set temperature. No effort needed! These are especially useful for larger grows.
Unlike humans, plants breathe CO2 and release oxygen. Many growers choose to add CO2 to their environments in order to increase yields. For setups with a lot of ventilation this is not likely to be necessary, however, for grow tents with low or poor ventilation this can offer a huge benefit for your crops to ensure the highest yield possible.
The main use for CO2 supplementation is what is called a “closed system”. In these systems the grow room is completely closed off from the outdoor environment, the lights are cooled on a separate system, and CO2 must be added to the system on a regular basis. This is an extremely advanced technique and is used to minimize contamination risk and eliminate any interaction of the grow with the outside world.