Five Basic Hydroponic Setups SYSTEM THREE: Hydroponic systems come in all shapes and sizes. You are really only limited by your imagination. Here are a few of the basic types of hydroponic systems to consider when you start thinking about using this method for your next garden HYDROPONICS, THE BASICS The most important thing for you is to realise is that Hydroponics should be easy. It is easier for the home grower to grow Hydroponically than in soil and that’s a fact! This is the reason for this booklet. In this booklet I hope to show you how easy, how inexpensive, and how satisfying Hydroponics is. Simply there is no easier way to grow, house plants,ornamental plants, vegetables such as tomatoes, lettuce, beans, fruit, root crops such as potatoes, carrots, onions, flowers such as roses and carnations, bulbs, vines, trees, orchids, herbs, anything in Hydroponics. To my knowledge, there is nothing that is grown that cannot be grown using hydroponic techniques. In Europe they call Hydroponics, “soil-less culture”. This is in fact, the best possible way to describe what we do. We take away the nutritional control of soil, by using a balanced liquid containing 99.9% water, and 0.1% of the Minerals found in soil. Instead of soil giving out some nutrient whenever it can, Hydroponics gives the right amount all the time. Hydroponic nutrient is totally organic (in terms of not artificial or synthetic compounds), except the minerals are mined from the ground and are then balanced to exact proportions, so your plant will get exactly what they need, nothing more, and certainly nothing less! In fact if we could take the perfect soil and dissolve it, we would have exactly what a nutrient solution is, totally natural, but under your control. Apart from nutrients, the most important thing we do in a Hydroponic growing design is make sure the plants have access to Oxygen. Basically, this means that they are not growing in water so they drown, but have a supply of air around their roots. I will explain more about this shortly. The burning question in your mind should be:- How do I get started in Hydroponics? This is the question I most want to answer in this book. I will discuss the major systems and hopefully lead you to the conclusion that Hydroponics is EASY. To get started in Hydroponics is as simple as deciding what system will best suit the plants I wish to grow? This question determines the type of system. The systems described further on explain whether they suit small plants like lettuce and herbs with smaller root systems or larger plants like tomatoes and cucumbers with larger root systems, short term crops like lettuce or long term crops that will be in the system for more than 3-4 months. Remember, plants such as tomatoes can be harvested and removed, from short-term systems, before they clog up the system with roots, but some crops will be harvested for long periods. E.g. flower and herb crops may cut without the actual plant being removed. These can be an extreme example, of a long-term crop, but their roots could be trimmed, or plants replaced with young seedlings instead of re-cropping. We’ll discuss more with each system. THE FIVE BASICS 1. LIGHT Light is the energy that creates life. Life cannot exist without it, and cannot thrive without enough of it. Plants process up to 5,000 foot-candles of light intensity to get the energy to grow. The sun is around 1,000,000 foot-candles. Shade can be lower than 1,000 foot-candles. Plants will enjoy much light, but some do not like all the heat put out by sunlight. Shade cloth is ideal for hot conditions, also to keep plants from, insects, wind, rain and other damage, but rarely is the requirement for low light levels. Sunlight is an ideal source of light for plants. It is bright and contains the Reds and Blues necessary to produce good healthy growth. However it also has infrared, Green and Ultra-Violet light. The infrared light or heat is absolutely necessary or we would all freeze to death, but it can be too little or too much heat. Too little heat is best combated by using a recirculating hydroponic system. By heating the nutrient in the tank, and pumping the 20 to 25C nutrient around we can keep the plants warm. Excess heat in summer, can be alleviated by cooling the tank, usually by aerating the tank heavily. By using a venturi, a water jet, or having the nutrient rising and falling into the tank like a waterfall will cool the nutrient as it passes through the air. It is not necessary to worry about green light as it is usually reflected off the leaves, making them look green. There is some evidence that shows that a reduction in Ultra Violet (or UV) light can improve growth. If you are growing under glass or plastic this may interest you. We generally grow outdoors, so just use common sense. If you’d feel hot or cold in the sunlight, then the plants would feel that too. Plants tend to grow well in the same climate as humans feel comfortable. A great way to grow is under artificial horticultural lights that will allow more control, and less damage from the elements, but that is a decision you can make. What I can tell you is that, a 400-Watt plant light, costs very little to run, but the benefits are, faster growth (from up to 18 hours of light per day), more control of the seasons through day length, less pest problems, no wind, rain and less cold problems. But you may need an exhaust fan to ensure good air circulation and no heat build up in warm climates. (See Appendix on Artificial Light) RULE: A PLANT GETS ALL ITS ENERGY FROM THE LIGHT IT ABSORBS THROUGH ITS LEAVES. LOWER THE LIGHT LEVELS AND YOU REDUCE THE GROWTH RATE. 2. OXYGEN TO NUTRIENT RATIO Oxygen keeps a plant’s roots healthy and allows the plant to take up nutrient. Oxygen is the key to growth rate. Without oxygen around the roots, the roots will rot and die. You cannot grow in water, unless you dissolve oxygen in it. The recommendation is that you do not grow in water, just feed enough nutrients to keep the roots moist, with access to oxygen. The 5 systems I have described in this book will have varying degrees of oxygen according to their design. The oxygen level or the oxygen to nutrient ratio is the key to success. RULE: PLANTS CANNOT TAKE UP THEIR NUTRIENTS UNLESS OXYGEN IS PRESENT. THE MORE OXYGEN, THE FASTER THE UPTAKE OF NUTRIENT. 3. NUTRIENT STRENGTH Assuming you have a commercial brand of nutrient made by a good Australian company such as Accent Hydroponics, Growth Technology or the like, you will get excellent consistency in the nutrient. Always use a 2 part A&B style nutrient where possible. Nutrients must be solely designed for Hydroponics. Soil fertilisers require bacteria to break down more complex elements into useful ones. They are likely to be less soluble, not pH adjusted, and are usually too slow to release the necessary elements to be suitable for Hydroponic systems. Plants may grow for a little while in Hydroponics using soil fertilisers but they generally exhibit minor mineral deficiencies, then develop major deficiencies, until even changing to a Hydroponic nutrient can not correct the disorders. Soil fertilisers normally kill hydroponically grown plants, but not overnight. Certainly they will never produce as nature intended them to if you do not supply the right amount of minerals in a soluble form. There are a range of companies offering a grow (High Nitrate) nutrient and a bloom (high Potash) nutrient. Neither will MAKE a plant do anything. You can use these formulas to approximate the nutritional requirements of your plants. When growing, a plant generally takes more nitrates, and during flower production and/or fruit production, plants generally increase their potash and phosphate uptake, but lessen their need for nitrates. However, in cloudy, overcast or short days of the year, the plants will take up more potash and phosphorus due to lower light levels, and on sunny, long, cloudless days the plants nitrate uptake is greater. Sounds confusing? It isn’t really. Most manufacturers put an excess of everything into their general-purpose nutrients. But when in doubt, ask a store. Also, when people tell you an imported nutrient is better, don’t believe them, unless they’ve tested a good Australian nutrient with a growth additive like Superthrive, Budwiser or Organic Growth Promotant (OGP). They will find out smartly, that these nutrients only grow a bit better because of the Americans and other countries put small amounts of hormones or vitamins into their nutrients – and imported nutrients cost more! Use Australian nutrients, and to boost growth, add a good plant hormone and Plant Vitamin treatment to the nutrient. You will be amazed! Once you have a good brand of nutrients, mix exactly to directions. Less is better than too much. Less will make a plant grow faster, but more stretched, and leafy than normal. More will create a compact plant that hardly grows upward but is extremely bushy, woody, but can be a heavy bearing fruiter/flowerer. If nutrient strength is strong or weak to the extreme, this will lead to deficiencies or death. E.g., too strong, and calcium is deficient because the plant is not taking up nutrient fast enough. If the nutrient is too weak, it is the same deficiency, but due to insufficient calcium in the nutrient. Follow directions and ask a store what to do. Nutrient strength can be read and adjusted by electronic conductivity meters. Ask your store what a conductivity meter will cost. (See also Appendix on advanced nutrient control through CF adjustment) RULE: THE NUTRIENT CONTENT AND STRENGTH GOVERNS HEALTH, HEIGHT, LEAF AND FLOWER PRODUCTION, AND ALL GROWTH ASPECTS. 4. NUTRIENT pH (ACIDITY AND ALKALINITY) pH is the level of acidity or alkalinity of the nutrient solution. Think of it as sweet and sour. Most nutrients in town water will be within the range of 6 to 6.5 pH. ALL PLANTS GROW IN THIS RANGE IN HYDROPONICS. Anyone who tells you otherwise, is either horticulturally trained in soil only or is reading materials drawn from soil based research and is therefore untrained for plant nutrition in Hydroponics. I extend my apologies to Horticulturists. Some of you do understand the nutritional simplicities of Hydroponics, but 4 years of soil training is hard to overcome, research into Hydroponics is still new, and soil nutrition is not suitable for the simple Hydroponic plant. If recycling nutrient, pH and Nutrient strength can change as certain elements are taken in by the plant. All you have to do is change the nutrient for fresh nutrient as often as possible, or adjust to the correct reading with a set of meters. If the nutrient is too sweet or too sour, the plants will develop deficiencies. I will discuss manual care, electronic adjustment, and computer control later. As discussed in water purity – pH must be checked if you are using rain, dam, bore water or any other source than town supply. RULE: pH IS THE KEY TO KEEPING PLANTS FEEDING ON THE CORRECT ELEMENTS, AND KEEPS THEM FROM DEFICIENCIES. 5. TEMPERATURE AND FRESH AIR Optimum temperature depends on the plants. Generally, Phosphorus up-take is severely impeded below 15 degrees Celsius, so that’s our bottom temperature. It is recommended to heat the nutrient if it is below 15 degrees Celsius for more than 4 hours per day. Maximum temperatures are, (as a guide) around 30 degrees Celsius but as long as it is well below the temperature where humans start to sweat the plants should be all right. Use common sense. If the plants are in 20-25 degree temperatures and 40-60% humidity, then it is likely that you would feel comfortable where the plants are. By coincidence, plants tend to grow best in climates approximate to human comfort. So if you visit your plants and it feels like a blast furnace, or a freezer, it is likely they would benefit from some attention on the matter. Fresh air is absolutely essential in shade-house, tunnel-houses, glasshouses and grow-rooms, as the Carbon Dioxide the plants breathe is essential for every plant process. Poor ventilation will kill plants, as surely as poison. You will notice ventilation problems by the better growth near vents, doors, or fans. If plant growth is more sluggish away from these areas, then you should improve your fresh air, or use Carbon Dioxide enrichment systems to add CO2. RULE: PLANTS NEED CARBON DIOXIDE IN EVERY PLANT PROCESS. THEY NEED FRESH AIR, NOT TOO MUCH HEAT OR THEY CANNOT PROCESS DUE TO WATER LOSS AND NOT TOO COLD OR THEY CAN’T GET THEIR FOOD. Plus one other basic: WATER PURITY Town water is generally suitable for Hydroponics, but if you are using bore water, spring water, dam water or rain water, you may have to check to see if this is suitable. What problems could occur, is the salt content of the water, may be too high, the zinc content from metal (zincalume) tanks, could make it toxic for plants (even though it may be still safe for us to drink), as well as any number of chemicals, poisons or fertilisers, could be contaminating the water supply. Please speak to a Hydroponic Company about the water supply if you are unsure. In all the above cases, pH control of nutrients is required. However town water is generally fine. Now we have looked at common sense approaches to growing conditions, we can identify 90% of problems and correct them. Let’s have a look at the five systems! SYSTEM THREE: Flood And Drain SETUP COSTS AVERAGE. RUNNING COSTS AVERAGE. EASY TO BUILD SOME PLUMBING. EASY TO RUN EASY. MAINTENANCE FREE VARIES BETWEEN TWICE OR ONCE PER WEEK. RESULTS EXCELLENT. Ingredients. Container or tray to be Flooded (Food Grade Plastic or Fibreglass). Irrigation Lines. Upper Level Drain System. Lower Level Feed System. Tank. Centrifugal Aquarium type Pump. Filter. Expanded Clay or Large particle (10-15 mm) Medium. Nutrients. Concept. Flood and Drain uses two cycles to feed oxygen and Nutrients to the roots. These are the Flood Cycle, and the Drain Cycle. FLOOD CYCLE: To get high oxygen into the root zone, we can flood the root zone with nutrients, and expel all “dead air” from around the roots. DRAIN CYCLE: After the Flood Cycle (2 to 15 mins) we can drain the nutrients quickly to draw or “suck” fresh oxygen into the root zone as the nutrients drain out and at the same time, leave the roots damp with nutrient. (15 to 45 mins) Sound Complicated? It’s as easy as Pump on and Pump off ! Design. To Design a Flood and Drain System we have to pump from a reservoir into the growing container or tray. We usually do this by pumping in at the lowest point. See Figure 3.1 (The Flood Cycle) The overflow in Figure 3.1 is the drain point during the Flood Cycle. This ensures the Growing Container does not overflow with Nutrients. The Pump is on and the Pump power keeps the nutrient “up” in the container. The Nutrients Flow in and fill all the spaces between the Expanded Clay and Soak the Roots with Nutrient. Note that the Nutrients are never Still during this Cycle. They are flowing up and out, through the over flow. Dissolved Oxygen levels in the nutrient are high because the nutrients cannot stagnate. During the Drain Cycle (Figure 3.2), the pump switches off, and gravity forces the nutrients back through the pump into the reservoir. There is a filter to stop any damaging particles getting into the pump. As gravity drains the nutrient, the spaces between the Expanded clay are left empty, and air rushes into the spaces left by the receding nutrient. The Flood Cycle should only be as long as it takes to fill the growing container or tray, and the Drain Cycle should be at least twice what it takes to drain the container. Usually 15 minutes on and 45 minutes off is enough. If any root problems occur, lengthen the drain cycle. During the night hours only have one flood cycle in the night, and one just before dawn. If heat is necessary, flood as normal during the night, but have one longer drain cycle during the morning and one in the afternoon to add extra oxygen. Set-up. The Growing Area should be set up with a pump connected to the inlet, and an overflow as shown in figure 3.1 and 3.2. The pump should be a submersible, and although you might think a larger pump than usual is necessary, it doesn’t usually hold true. If the pump has to pump high, measure the distance between the height from where the pump will be in the reservoir, to the height where the overflow will be. We are only interested in height vertically, not distance horizontally even if the tank and growing area is several meters away(horizontally) from each other. (The following is an approximation of pump pressure only. It can vary in practice). If the height of the system was 1 meter, and you have a 600 litre per hour pump with a 1.4 meter “head” of pressure, then you will have 0.4 meters of pressure to fill the flood area 0.4 x 600L ph = 240 Lph. 240Lph =60 Litres per 15 mins, so you can flood a chamber of approximately 60 Litres if you flood for 15 mins. Tank size in Flood Systems should be at least 1 and a half times the growing area. (Expanded Clay takes up a lot of the volume, so the nutrients required to flood the area is not even ¼ of the growing area size) Inlet: The Inlet should be at the lowest possible point to drain the growing area. Wherever possible, complete drainage will give you the best results. Some sort of Screen should be placed over the inlet so that it does not become blocked with expanded clay during the drain cycle. If the screen is fine (like stockings), it will block with the fine particles and the system will remain flooded. Use a wide mesh made of plastic like a ¾ inch Phimac Foot Valve Screen. This is large enough to not block, and small enough to block expanded clay from falling into the inlet. (Never use metal in Hydroponics. Use plastic parts, or stainless steel, because metals will react with the nutrient) Overflow: See dig 3.1 and 3.2. Set the overflow at least 1 cm below the top of the media, or the plants can be dislodged from the expanded clay when it over-floods the media. Again, use a screen so that the expanded clay will not fall into the overflow. Use an “in-line” filter between the inlet and the pump to collect any fine particles. Clean it regularly if you notice it is picking up any expanded clay particles. If you have any problems, discuss it with your local hydroponic store. Propagating. Propagating in Rockwool cubes, or perlite mix is required to give the seeds a chance to germinate and develop a root system. Flood systems usually don’t give a good result for propagation because the medium has very little water holding ability. For striking cuttings, inset cutting into expanded clay, and put some liquid rooting hormone into the reservoir. Cuttings strike very well this way, but you should shield them from very hot or dry conditions or bright sun. Misting them should stop them drying out before the roots have developed. Maintenance and Problem Solving. I usually would advise people to keep an eye on their plants. If the stem and leaves wilt, then increase the number of floods. If the leaves wilt with yellowing of the leaves; you may have too many floods and the roots are drowning or rotting. Immediately increase the amount of time between flooding. As a guide, try flooding 15 minutes out of every hour, by setting a household timer such as a Kambrook KD84 (15min increments) to that period. I miss out 3 to 4 floods a day, during the night, or during the morning or afternoon. The reason I do this is to give the roots a chance to get a bit more oxygen. But if the plants are cold at night, and I am heating the solution, I would not give them any breaks during the night, using the morning or afternoon to give the system a break. If I have a choice, then breaking the flood times during the day is always my second choice. Nutrient Changes should be performed regularly, if you have no electronic test equipment. For a 20 to 40 litre tank, feeding around 2 to 10 plants, I would change every 7 to 10 days. If more plants are using the solution, then change more often, and use common sense. If your plants start looking less than perfect, try changing more often. Take a sample of your nutrient into a hydroponic store and ask them to test it for you. take a fresh sample from when it was first mixed up, and a sample before dumping. This will give you reference to how the nutrients are going. Flush the expanded clay every 4-8 weeks with a weak nutrient, just in case any nutrients build up on the expanded clay. This can occur if the plants use a lot of water, and leave the nutrient behind. This is called salt build up. Some people get this problem, some don’t. Clean the filter if the system is not draining quickly. Growth Rate. This system is known for unbelievable growth rates when it is really well run. Even without nutrient management, and control, the high oxygen ensures good growth rates at all times. Heat and Cold Control. Since this system uses intermittent pumping cycles, the only time we have complete control of the nutrient is when the nutrient is flowing in the growing container. When the Growing container is drained of nutrient, the temperature is affected more by the air temperature. If heat or cold is extreme, consider using more flood cycles during that period of the day and less at other times. An example might be, very cold at night, and medium hot in the day around noon. Then you could flood more at night and miss a flood in the morning and one in the afternoon. Don’t flood for longer, but have less of a period for draining. Heating the Solution is an effective way of controlling the temperature. If the weather is hot, you will find that nutrient will cool enough generally because the nutrient flowing into the growing chamber is falling back into the tank through the overflow, and the aeration is cooling the nutrient enough. Further Aeration should cool the nutrient further if required. Suitable Crops. Flood and Drain is excellent for permanent crops, Herbs, Flowers, and all crops. Harvesting plants usually means taking some of the media with the roots, so I do not usually grow short-term crops in flood and drain, but it works very well. If root crops are grown, make the expanded clay a fine grade, and keep flood cycles far enough apart so that rotting does not occur. Root Crops will do better in a Pot with Perlite really, but you can give it a try. Striking cuttings with a Flood and Drain System is excellent, just add some rooting hormone to the nutrient solution. Too many floods could lead to stem rot in this case so halve your flood cycles, or keep a good eye on your cuttings. Set-up Costs. Pump, Expanded Clay and Growing trays make this a medium cost system to set up. Some trays can cost a lot. For Price, if you are setting up the system yourself, use plastic tubs and more of them, than trays. Trays are cheaper when buying a complete kit, because stores find the labour time shorter and less framework to build more inexpensive, and generally discount the pump and media. A small tub system should cost less than $200 and full Trays up to 1 square meter in size should only cost $350 to $400. They are excellent when pre-built, but check they have included a filter for the pump, (unless they are the top feed type). Running Costs. Running costs are medium because the larger tank holds more nutrient and should still be adjusted or dumped regularly. Also the replacement of media adds cost because when plants are removed, as they can take some expanded clay away with their roots. Offset against running costs is the excellent growth rate. I would rate this system a top performer. So yields can offset the cost. Options. Flood and Drain Systems have a disadvantage in that normal automatic filling systems using float valves are more difficult to set up as the reservoir will be lower during the flood cycle and higher after the system has drained. We should set up the float at the minimum level, and ensure no leakage around the float valve fitting. Fig # 3.3 The different reservoir quantities at flood time and drained time can make nutrient dosing computers difficult to organise as it may adjust the tank and find that during a different cycle the nutrients need a radical readjustment because the total volume of the tank changes. However, using diagram #3.4 we can see a timing system for dosing equipment that should optimise the computerised flood system. Variation on Feed System -. A flood and drain system using a top feed. Nutrient pours into the top at a faster rate than the smaller holes at the bottom can drain. The overflow is still present, but when the pump switches off the system drains slowly. The bottom holes can block with small media particles, so ensure there is a drain coil (not a foam or cloth filter) around the drain point to keep them clear and allow you to check them for blockage. This system has the advantage of saving your pump from grit and cleaning, but is less responsive if the system does not drain quickly enough. Variations on Materials. There are purpose built flood trays, which drain completely with no pooling at the base of the growing tray. These are better than normal buckets, boxes or other containers. For DFT or Deep Flow Technique, we can use channels, or even round pipe, but flat bottoms make it easier to plumb fittings, and round pipe can only be fitted at the end caps. See DFT later in this book. For efficient draining, ask for a ¾ inch Foot Valve (Screen Only), made by Philmac. They are a drain cover with openings too small for expanded clay, but big enough to drain quickly. They are also, very easy to plumb. Conclusions. Flood and Drain is a very high powered system, and will give you much higher yields than similar systems. It is too tricky and expensive to consider on a large scale, and running costs versus yield is lower than NFT. You will have fun with Flood and Drain, because there is more experimentation for the grower than with normal systems, and root size doesn’t matter as much as NFT as the roots don’t usually choke up when large like they can in small NFT channels. One of my favourite systems for those who like to tinker around, and “play” with their plants.
Posted on: Thu, 03 Oct 2013 22:58:49 +0000
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