What is hydroponics?
Put simply, hydroponics can be defined as growing plants without using soil.
Plants are supported in an inert medium, for example a rockwool cube, and are fed a nutrient solution. This nutrient solution contains all the elements a plant needs for healthy growth and takes as much or as little nutrient from the solution that it needs. This means that rather than concentrating energy on searching for nutrition, the plant focuses all its energy on foliage and flower growth. Growing hydroponically generally delivers 30%-50% extra yield with much faster growth rates than alternative growing methods. A typical crop turnaround period (from cutting to harvest) is between 12-14 weeks.
Growers that cultivate hydroponically have full control over their plants development. By feeding different levels of essential elements at different stages in the plants life cycle it is possible to accelerate root development, stimulate - or slow - vegetative growth, and then trigger and enhance flowering.
As well as constant availability of water and nutrient, plants grown hydroponically also have an abundant supply of oxygen to their roots.
Hydroponic growing medium such as clay pebbles, coco or rockwool have an open structure that provides a highly oxygenated root zone and hydroponic techniques such as NFT (Nutrient Film Technique) and Aeroponics are essentially ‘bare rooted’, leaving plant roots open to absorb as much oxygen as possible.
This constant supply of oxygen, nutrient and water accelerates plant growth and leads to increased yields.
What is active and passive hydroponics and what is the difference between them?
Hydroponic systems can be characterised as either ‘active’ or ‘passive’;
Active hydroponics is the technique where nutrient solution is actively delivered to the plants roots via a pump, whatever the plants do not use simply drains away.
No absorbent growing medium is necessary in active hydro; this allows an abundance of oxygen into the root zone. The constant supply of oxygen, water and nutrients leads to optimum growth and yields.
Passive hydroponics is the technique where nutrient solution is constantly made available to the plant via the capillary action of the growing medium surrounding the roots, there is no pump involved.
Although much more effective than traditional growing methods: passive hydro relies on absorbent growing medium and this limits the amount of oxygen in the root zone.
Growers looking for a simple introduction to hydroponics and the next step up in performance from hand watering pots and trays should try passive hydro, also look at our Autopots section.
Growers looking for the maximum growth and yield possible should always choose active hydro.
Active hydroponic systems explained.....
What is NFT?
NFT stands for Nutrient Film Technique. These recirculating hydroponic systems consist of growing channels or trays over which the nutrient solution is constantly pumped across, creating a nutrient film into which the roots grow. Plants are often started in rockwool cubes and placed on the growing channels. The channels should be covered so the roots can extend out from the cubes forming a large root mat across the channel. The solution is recirculated from a main tank.
What is Ebb & flow/Flood & Drain?
Sometimes known as ebb & flow, flood & drain systems periodically flood the entire root zone with nutrient solution before it dries out. This is done with a timer on a pump from a main nutrient tank usually located directly below the flood tray. The root zone is flooded for short periods of time (between 10-15 minutes). The interval between floods will depend on plant size and medium used (rockwool or expanded clay pebbles).
What is a Run-to-Waste system?
As opposed to a recirculating system, run-to-waste systems do not run the nutrient solution back to a main tank after circulation. The nutrient solution is used once and collected in a separate tank never to be used again. 10% run-off (the amount of waste nutrient in comparison with your start quantity) is sufficient for good results. Try to keep your waste to minimum. In third world countries, run-to-waste systems where no run off waste is achieved are very popular for water conservation.
What is a recirculating system?
As opposed to a run-to-waste system, the nutrient solution is returned to a main nutrient tank for recirculation.
What is the best hydroponic system?
Put simply, the one that suits you the best! The answer will be based on your individual requirements, for example your grow room size, number of plants, budget, etc..... Call us on 01904 479979 to discuss your personal requirements
Is hydroponics complicated?
Not at all - There are hydroponic systems tailored to every level of ability, each one capable of delivering great results. As long as you follow product directions and keep to a few simple regular steps your plants will thrive. Once a gardener gets used to the routine you will be amazed at how simple it is. Often, a gardener will wish to develop the hobby into a more complicated set up or system.
What are the advantages of hydroponics versus soil grow plants?
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 though 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 produce 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 re-potting. As hydroponics is clean, it can easily be used indoors or in spare room as well as a greenhouse or conservatory.
What type of plants can be grown hydroponically?
Anything can easily be grown, but some make more sense than others. Plants we recommend are; tomatoes, strawberries, peppers, hot chillies, lettuce, chard, cucumbers, courgettes, broccoli, beans, snow peas, herbs, as well as all types of flowers and house plants. Banana and tobacco can be easily grown also, even in the UK!! Root crops such as potatoes or carrots are more difficult to grow and are less cost effective due their low price in the shops.
Can plants be grown organically in hydroponics?
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, realise that as long as the produce is fresh, pesticide free and healthy it makes little sense to stick to the historical position. With full spectrum hydro-fusion organic nutrients now available, such as the Earth Juice sugar peak range, hydro-organics is now a reality with an ever-increasing number of converts.
Is Hydroponics Expensive?
Just as in a normal garden you can decide how large or elaborate you want your hydroponic set up to be. You can buy a simple system from as little as around £30.00. Once you have your system the annual cost of nutrients and pH control products for a system that could produce kilos of tomatoes (for example), can be easily calculated and in addition you would have a very rewarding, educational and healthy hobby.
Will my crops taste ok?
Definitely and perhaps even better. Most commercially grown crops are grown to look good, travel and store well for shelf life, not for flavour. When you grow your own plants hydroponically they are receiving all the nutrition they need, you will be amazed just how good they do taste.
Will I need any pesticides, if so what kind?
Generally, the level of pest problem will be less than soil grown crops for reasons already stated. However, if pests do become a problem you can choose to use spays such as pest off, spray safe, smc, neem repel and others, just look in our pests and diseases section. All of these controls are highly effective and completely safe to use on edible crops for the elimination of spider mites, aphids, fungus gnats, thrips etc
What is the best Growing Medium?
There is no simple answer to this question as different mediums are more suited to different systems or plants. A good hydroponics media should support the plants in the system, absorb and retain moisture, be porous to allow air circulation and proper drainage, protect plant roots from temperature extremes and not breakdown. Here’s a brief run through of the most common.....
Rockwool.....
At Elements we sell Grodan Rockwool , which is the undisputed stonewool champion in the hydroponics market and is used by both commercial and hobby gardeners throughout the world. Is an in-organic, sterile, inert growing medium formed from a combination of basalt rock, limestone and silica. Rockwool has the best water and air holding capablilities will enable the gardener an easy set up as it is pre-formed and modular. Rockwool will maintain a 60/40 water to air ratio which results in faster growing plants with more thorough root distribution and also acts as a buffer against drying out in the case of a system or pump failure. Rockwool slabs may be used in hand water systems, drip systems and even flood and drain. Rockwool cubes can be used in Nutrient Film Technique (NFT), drip feed and flood and drain also. For starting seeds and cuttings Grodan Rockwool is the preferred medium. For hobby growers, Rockwool is generally used for one crop only, but today as most Grodan rockwool is produced from recycled Grodan, its environmentally friendly too.
Clay pebbles.....
Hydroton clay pebbles are clay, kiln fired pebbles that are completely inert and sterile. They are uniform clay pebbles and we believe they are the best clay to use. Hydroton is the only clay pebble that offers a smooth round surface, eliminating sharp edges that can cut delicate roots and harm plants, making them vulnerable to pests and diseases. Hydroton drain freely and do not hold any excessive water and will hold a small amount of nutrient between irrigation cycles, which is why they provide good oxygen levels around the root. Hydroton may be cleaned and sterilised and can be used again and again. Hydroton is the preferred media for pot based flood and drain or dripper systems like the IWS and wilmas.
Coco.....
Coco Coir is a relatively new media to the hydroponic market. Coconut Coir is rapidly becoming the media of choice for both soiless gardeners and soil based gardeners who are concerned about the depletion of rare peat bogs in the world. Coco Coir is a waste material from coconut production, is 100% renewable and an environmentally friendly product. Canna Coco Coir is the market leader in Hydroponic Coir media, this is due to the high quality and pre-treatment necessary for coir to be used in soiless gardening. Canna Coco Coir has been pretreated or washed to eliminate the high level of salts often found in the raw material. Other Coconut Coir's on the market are often unsuitable for soiless gardening due to these high salt contents. Coco tends to be used in hand watering and drip feed systems and needs a specific nutrient formula due to it being buffered differently to soil.
Perlite and Vermiculite.....
are two lesser used hydroponic mediums. They tend to be smaller in actual size and therefore can block pumps and systems, but work well in DIY soil mixes and traditional wick systems. Perlite is a great hand watering media which provides good aeration for the plants but holds little moisture. Vermiculite does hold moisture well but tends to offer less in the way of aeration. As a result these two media are often mixed in a 50:50 ratio.
Finally some systems are media less, such as the amazon, xstream or aeroflo aeroponics systems. In terms of media, these are the most cost effective systems as they may only need a few 2.5cm (1") rockwool starter cubes. Although plant growth is excellent with these kinds of systems, as there is now no media to buffer either the plant or the system the plant will be at risk from pump failures, fluctuations in temperature or uneven watering. This results in a more volatile environment and therefore not ideally suited to the beginner hydroponic grower.
Nutrient & Management
How do I know whether to use hard or soft water feed?
Officially, hard water is anything over pH 7. In practical terms, for growing plants hydroponically hard water feeds should only be used for very hard water generally with a pH above 7.8 and a cF value above 8-9. Soft water feed should be used in all other cases and the water will need to be pH adjusted with either nitric or phosphoric acid. Some of the nutrient companies offer universal feeds to cater for all water hardness levels, eliminating the need for this question all together.
How do I test and adjust my pH?
Electronic pH pens are available from £39.00 upwards for instant and accurate readings. Some people still like to use manual indicator kits which are easy to use and are available for £4.00.
Why do I need to test my pH?
When growing hydroponically, the nutrients are more available to the plants if the pH is between a range of 5.4-6.7. Ideally keep your ph close to 5.8 throughout the growth cycle and this will eliminate nutrient lock out or toxicity problems occuring.
What's the ideal water temperature for my nutrient?
Your nutrient solution should be between 20-23 degrees Celsius.
How do I know what and how much nutrient and additives to give and when?
All the nutrients we sell at Elements can be supplied with tailor made grow schedules. These are easy to use and take all the guesswork and need to calculate away from you. Simply follow them week by week!
How often should I change my nutrient solution in my hydroponic system?
It's best to change the solution every week to ensure optimum results, especially when the plants are bigger and eating/drinking more. However when plants are young every 2 weeks should suffice.
Should I adjust my pH every day?
In recirculating systems (NFT, Flood & Drain) the pH will fluctuate on a daily basis. This is normal. Do not adjust the pH every day, rather every two or three days to avoid build-up of phosphoric acid (ph down) in the system.
Do I need to introduce oxygen to my nutrient solution?
Although not necessary the addition of oxygen can often be of benefit in helping the plant perform in demanding environments. Put simply, more air equals more yield!
What is the best way of introducing oxygen?
Both by the use of adding oxy-plus (H202 liquid) to your nutrient tank and air pumps with air stones are good ways of introducing oxygen. Using air stones will also help keep the nutrient solution moving and reducing stagnant water as well as keeping everything evenly mixed.
Do I need a nutrient heater?
In the colder months theses are particularly of benefit as they will prevent the nutrient solution from getting too cold when the lights are off. Maintain nutrient temperatures between 20-23 degrees Celsius.
What is the best additive to increase yield?
Again its about finding the best additive to match your needs, taking into account your budget and the stage the plants are at, etc..... the most popular place to start is with a PK product which is a phosphorous/potassium boost for mid to late flowering. This product should increase yield and weight of fruit and flowers. Add this to your bloom feed. Call us for further advice.
Lighting
Simply put, more light equals more yield!!
Light is the most important environmental factor to consider whether growing in soil outside, or hydroponically inside, or in a greenhouse.
Depending upon where you live and where you want to garden the sun will not always be there for you. With a light kit from Elements you can literally grow any plant, anywhere and anytime !
What's the best lamp to use?
For early vegetative growth look at our propagation lighting section, but light loving plants need more light as they get bigger, so it wont be long and you’ll need to get your plants under a metal halide or dual spectrum HID light kit. Once you’re in flowering you can either stick with the dual spectrum or switch your metal halide for a sodium lamp. Call us for more detailed advice to match your exact requirements.
How close should I have light to my plant?
This generally depends on factors like size and height of growroom and whether you have an extraction system. As a rough guide, with young plants, approx 4ft is a good start point. When the plants are big and strong, you may be able to get your light 2ft or even closer without burning. It is important to keep your plant healthy so always err on the side of caution and keep a close eye on them in those first few hours after you’ve moved your lights down.
Should I be using a heat shield with my light?
As well as acting as a heat shield, they are designed to produce an even spread of light over your garden. They reduce hot spots under the lamp without reducing yield. It could be said that heat shields would be of benefit to everyone using HID light kits!
I want to put a timer on my light system. How should I do this?
On fluorescent systems, a standard digital or mechanical timer will do. On H.I.D. (High Intensity Discharge) lights such as 250W and larger Halide and Sodium systems, a normal timer would blow without the use of a relay/contactor. These relays/contactors are used in conjunction with a normal timer and allow you to switch from one, up to eight lights on the one timer system. Relays and contactors start from approx £25.00.
What are the advantages of air-cooled lighting?
At Elements the air-cooled lighting we sell is either the Supernova or the tubular type Cool Shades in 5 or 6-inch diameter. These are very efficient at reducing heat as an extractor is attached directly to the end of the reflector, so the heat is sucked straight off the lamp. This means that your lamp can be lowered directly onto your plant and that both quantity and quality is often improved due to the reduction in heat and stress.
How often should I change my bulbs?
For high output Sodium and Halide lamps, you should change your lamp at least every 9 months. This is because the performance of your bulbs steadily diminishes from three weeks after initial firing. From this point it is a straight line down in terms of performance versus time. If you leave replacement of your lamp longer than this you often lose more yield than the cost of a new lamp, so its not really worth it.
Environmental
My growroom smells what should I do?
he first step that we always recommend is that you add a carbon filter to your extraction system for odour elimination. These connect to the extraction system in your growroom. Call us for further advice on size requirements and installation. Moving on from there we offer other air purification products like ozone generators and ona gels for the complete removal of unwanted smells.
What's the ideal room temperature for my growroom?
When your lights are on, the ideal temperature for your growroom should be 24-27 degrees Celsius (in the shade) for most light loving plants. When the lights are off, the temperature should be between 21-24 degrees Celsius.
Do I need an extractor?
We would always advise that you need an extractor. Not only to remove all the C02 depleted air, but you will always get better results with one and it will pay for itself very quickly in extra yield and better quality.
How much air exchange do I need in my growroom?
There are many factors to take into account for this. As a rough guide, 20 plus air changes per hour are necessary. The less headroom you have and the more lights you have, the more air exchange per hour you need. Give us a call for us to calculate and match to your exact requirements.
How often does my carbon filter need changing?
This depends on which type of filter you purchase. Our economy carbon filters have an expected life span of generally 6 to 12 months. They are not refillable so then need to be placed. If you choose to invest in the Mountain Air brand though, these carbon filters are expected to last you 3 years!
My temperature gauge says my room is too hot, but my plants seem fine. What should I do?
Are you using an inlet fan? It is usually of benefit to install an input fan as it will help cool your room, although the inlet fan can only bring air in as cool as the air outside. In a two or more light situation we would advise in turning a light off or possible introducing some low output supplementary lighting until the temperature subsides.
What is the ideal night-time growroom temperature for my light loving plants?
For optimum growth rates, it is best to keep night temperatures between 21-24 degrees Celsius. Below 21 degrees Celsius may affect your yield although not your plant health. Try to keep temperatures as ambient as possible.
Would I normally have to run my extractor all the time?
You only need to run your extractor at the times when your light is on.
How can I quieten my extraction system?
Acoustic ducting is available from Elements and will significantly reduce the noise made by the air entering and leaving the fan which is the primary source of noise with most fans. Speed and climate controllers can reduce noise significantly and remember 20% less speed is about 40% less noise!! Silencers are also available and acoustic fans rubber mounted inside acoustic boxes are available too. Call us to discuss your situation and requirements.
Plant Health
My leaves are curling up. What does this mean and how can I stop this?
Leaves curl up at the margin and tip in an attempt to retain water. If they are curling up, this would indicate slight environmental problem: Either your light is a little too close to the plant or your oscillating fans are drawing too much moisture from the leaves. To remedy this problem, move your light up and make sure oscillating fans are not blowing too heavily on the leaves.
My leaves are curling down. What does this mean and how can I stop this?
This condition is more commonly known as ‘rams horn effect’. Similarly to upwards leaf curling, the plant is trying to retain moisture by reducing its leaf surface area. A downward curl would indicate that your nutrient solution is too strong or you are watering too heavily. To remedy this problem, reduce feed strength, reduce your watering cycle, move your light up and make sure oscillating fans are not blowing too heavily on the leaves. Be patient and call us for more assistance if the problem persists.
My big bottom leaves are losing colour. What's wrong, and how can I stop this?
This would be quite normal in a high light situation. The large leaves at the bottom of the plant will lose colour as they get old and younger leaves nearer the light will take over as the main leaf engines of the plant.
I have rusty spots/marks and light colouring on my leaves. What does this mean?
There could be a multitude of reasons for this problem occuring. Check for bugs, especially on the undersides of the leaves. If no bugs are present it could be an environmental or nutrient problem. Take immediate demands off the plant (move light up, check nutrient strengths and pH, to relieve stress) and call us for further advice and trouble shooting.
My leaves are yellowing, what does this mean?
Again there could be a multitude of reasons for this problem. Check your nutrient solution or make a new solution. If this is OK your light may be too close or your night temperature too cold. Call us for further advice and trouble shooting.
Plant cultivation
What's the best medium for rooting cuttings?
Small rockwool or root riot cubes are by far the most popular propagation mediums as they tend to give very high success results.
How much light do I need to root my cuttings?
A fluorescent tube or two is generally all that is required over a propagator. This is ideal as the cuttings will not get too hot and they provide enough light to root all cuttings. Check out our propagation lighting section.
My cuttings will not root. What's going wrong?
Make sure your cubes are in a propagator under the correct type of light, are not too wet and the cutting is firm in the cube (not wobbly!). Ideal humidity is 75-85% RH. Ideal temperature is 21 -27 degrees Celsius. There could be a whole host of reasons for this happening, call us to discuss if all of the above are correct and the problem persists.
Once I've rooted my cuttings in rockwool or root riot, what can I then plant them on into?
Once cuttings are rooted into small cubes, they can generally be transplanted into any of the growing mediums we sell at Elements or any kind of system.
How do I increase my yield?
The most important factors in a successful garden are 1. Good quality plant stock 2. Lots of light 3. Good air exchange. A good active hydroponic system will always increase yield too. If you are happy with these, please feel free to try different feeds and booster (additive) products in an attempt to find what works best for you with your plants and your garden. All Elements we only sell premium branded products which are tried and tested and as a result we have complete confidence in all of them and would recommend them all. To us, its all about matching our products to your needs and at Elements we are happy to discuss your options and assist in how you can go about achieving the best results!
Happy Gardening!
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Topic: What Is Hydroponics A Great Article For The Enthusiast (Read 4082 times)