Common Mistakes Made by Hydroponic Beginners



Going Into the Room When the Lights Are Off


Put simply this is a no, no! You might be excited by your new hobby and be tempted to look at your plants 50 times a day. Save it for when the lights are on.


Pulling Leaves off the Plants


Leaves are sugar production factories for the plant. This sugar is critical to healthy flowering. No matter what anyone tells you, refrain from taking the leaves off the plant. There may be some benefit for inducing a growth stress response which can help in reducing stretch but this practice can be detrimental to growth and is best left for when you are a bit more advanced. 


Adding Nutrient and Water Every Time that you Top Up the Hydroponic Nutrient Tank/Reservoir


This applies to those of you who are using tap water in recycling Systems:


Tap water has salts in it. Then you add salts to it (in the form of nutrients) that is taken up by the plants in varying degrees. You then add more water that contains salts and more nutrient (salts). What can happen is that the salts become very imbalanced as a plant food and too concentrated. This imbalance and over concentration can harm the plants. In a worst case scenario the plants can burn.


You are better off just topping up your tank with water (and not adding nutrient) to a level where the desirable salts levels register on an EC meter. Over the course of several days your water/nutrient levels in the tank get lower. That is, less volume of nutrient/water than when you first started. After 5 days or so you dump your nutrient and start again. Most experienced growers (who use recycling systems) know that the bigger their nutrient volume the better, and that the more regularly they dump their tanks the better.


Point being – just add water to the level where the salts are maintained at their desirable levels.


Using Cheap, Unreliable Equipment for Very Important Jobs


It’s easy to say, but try not to skimp on important equipment such as timers, fans, and lights. OK, so your budget is limited. This means that you have no choice but to shop on price. What you may find is that later on when you have saved a bit more for your hobby you can invest in better quality equipment. Quality means more reliable equipment, fewer equipment failures, and safer gear that is designed for heavy-duty wear and tear.


Not Double Checking that Equipment is Set and Running Correctly


Things like forgetting to plug your pump back in, not checking that your timers are set and working correctly, and not checking that your meters are calibrated and working correctly can cause all sorts of problems. Check and recheck your equipment and settings.


Taking on Practices, Based on Unqualified and/or Dubious Advice



When you first start growing indoors, it is only natural to be a bit confused by all the technology and principles that underpin high yield hydroponic gardening.


At first you may find that you get all sorts of advice from friends and/or other people whom you encounter. Seemingly, everyone – but you – will know the best way to grow. The only problem is that much of this advice will likely contradict the other advice that you are getting. So who do you listen to?


My advice….


Listen carefully to what is being said and then question why anyone thinks their way is best. If their answer is not bound by solid plant propagation and growth principles, be wary of what is being said. It could be great advice that you are receiving, but then again it could be ill-founded advice.


In addition to this, take time out and do some reading about what makes plants tick. We’ve tried to supply information on this site that gives you a solid understanding on what plants like in their environment. Use the ‘grow info’ menu link on the site  and take time out to read the numerous articles that are written by G.Low – the author of Integral Hydroponics. Other than this, we strongly recommend that university sites on agriculture and plant science are great sources of information.

Additionally, many online agricultural magazines such as Practical Hydroponics and Greenhouses magazine and GPN magazine (Greenhouse Product News) can provide extremely good information while a few of the more ‘hydro’ retail industry driven magazines (no names mentioned) can be heavily influenced by advertising revenue, which can taint the quality of the information.

As a guide for evaluating the quality of web based information:

  • Anyone can create a Web site. It is important to find out the author’s identity and his or her qualifications or expertise in order to determine the credibility and reliability of the information. I.e. is the author well-known and well-regarded in the field of which he/she writes?
  • Is the information reliable? What qualifications or expertise does the individual or group that created the site have?
  • How accurate is the information presented? Are sources of factual information cited? I.e. does the author cite references to academic literature/research etc?
  • Is it an official academic or scholarly Web site? Is the organization recognized in the field?
  • Compare the page to related sources, electronic or print, for assistance in determining accuracy.
  • Does the page exhibit a particular point of view or bias?
  • Is the site objective? Is there a reason the site is presenting a particular point of view on a topic?
  • Does the page contain advertising? This may impact the content of the information included. Look carefully to see if there is a relationship between the advertising and the content, or whether the advertising is simply providing financial support for the page.

I compiled this list after looking at numerous credible academic sites about what sort of criteria should be used to establish the credibility of web based information. When using this list it is notable that forums and many commercial sites would rate very poorly.


Bottom line…..Give the forums a bit of miss if you’re trying to learn to grow and instead spend your time reading material written by educated and informed researchers and agriculturalists. Not to pay out on forums because certainly they can be a great resource for information. The problem is that as a novice you first need to be able to discern between good and bad information.


The more you can learn about plants and their science the more empowered you will be.


On the other hand, if all you are given is a rigid system of growing (eg. “do this, this and this and you can’t go wrong”) you are trapped within that system. The only problem is, what if something does go wrong? All you know about plants is confined to a system that really hasn’t given you knowledge on plants and their ideal environment.


Probably worth mentioning also is to find a hydroponics supplier that will take time out to answer any questions that you may have. A good supplier can generally give you well rounded advice based on all aspects of growing. Again, however, listen carefully, as it is in their interests to sell you products. Your supplier should offer you a wide range of different product choices and systems to suit your needs. Be wary of suppliers who are pushing one type of methodology or system; this may suit their needs but will ultimately fail to give you a wide range of options and knowledge. The hydroponics retail industry is a service industry. Make sure that you are confident about the service that you are getting!


Designing Your Own Breed of Hydroponics System


Why reinvent the wheel when (far more) qualified people have done it before you?


If you’re short on funds and can’t afford a system do your research before setting about designing your own system. Many principles should be adhered to when it comes to building a hydroponics system.  Ideally copy a system that you see in a hydroponics store. Cost compare what it will cost you to make yourself against what you can purchase it for. You may be surprised.  (Read more about hydroponic growing systems here)


Interpreting ‘Hydroponics’ as Constantly Wet


Hydro meaning water can be a bit deceiving. Root system health largely depends on a good oxygen/moisture ratio within the medium that surrounds the root zones of the plants. For this reason it is important that the medium isn’t over watered.


Changing the Entire System When Things Go Wrong


If your system is based on a design that is known to work and something goes wrong you will need to analyse what has caused this. Often growers blame their equipment when things aren’t quite working out.  Sometimes they start from scratch and change everything that they are doing. The problem with this is, if things do go wrong again they have no starting point to cross reference against what went wrong the time before  (as they have changed everything). It is better to work through the problem, a bit at a time, than to drastically change things every time something goes wrong. Through this process you can eliminate factors that may or may not be the cause of your problem.


Thinking High Humidity is Good for Plants


Your grow room environment should ideally have humidity levels between 45 – 65% dependent on the phase of the crop cycle. For some reason there is a misconception among some growers that the humidity levels should be extreme (80 – 100% etc). This is not the case.


Reading outdated Literature


There are many books out there that were written many years ago. Much of the advice in them is very well rounded; however some of the information is out of sync with modern day hydroponics. Don’t take any one book as gospel. There is a very good chance that if a book was first published in 1984 etc it is a bit out of date. The hydroponics industry has a tendency to improve things based on new technology and research.


Running Before You Can Walk


The KISS (Keep It Simple Stupid) should apply when you first set out on your hydroponics journey. Don’t go getting ahead of yourself. Simple = less complex; less complex means easier to analyse any problems that you may encounter.


Using Too Many Additives


This is part of the KISS principal. Additives can help your plants. For instance, a root stimulant in the first week of grow, some silica during the rest of grow and early to mid bloom, and a bit of a boost with potash in mid bloom would likely ensure that the plants get everything that they’re looking for. However, this too isn’t absolutely necessary if the plants are getting a good nutrient along with some silica (read more about silica here).


What some growers do is hit the plants with all sorts of additives because their retailer has a snake oil for everything, or their friends heard about some ‘new beut’ product etc, etc, etc. As a learner, however, if something were to go wrong you would have to add all of the additives into the “what went wrong” sum. My recommendation? Use a good nutrient, a root stimulant in the first week of grow, silica throughout your grow and hold back with the rest until you come to terms with what it is that you are doing.


By the way, I don’t class root disease preventives as additives. They are a must! Therefore, I recommend the use of friendly bacteria or another root disease preventative in your nutrient tank throughout your grow. This will help to ensure (along with the correct water/nutrient temperatures) that your plants’ root zones remain healthy.


Not Enough Light


Light is the most important element of photosynthesis. Light is the energy that makes it all happen. Some absurd claims have been made about the power of HID lighting. Unfortunately the suppliers of the lights have sometimes made these claims, when selling kits to beginners. One example – “A 400 watt light will cover 2mtrs2”.  This is true. However, half of the 2mtrs2 will have insufficient light levels to promote healthy plant growth.  I recommend a 600 watt light per square metre.


Insufficient Ventilation


“Air In – Air Out”


Adequate ventilation is an important aspect of successful indoor growing. Often beginners don’t realise the importance of adequate ventilation. There are two things that need to be considered:


  1. Adequate ventilation (exhaust) to ensure that the area doesn’t become overheated due to the use of HID lighting.
  2. Adequate inlet air to ensure that you don’t work your exhaust fan under pressure. There is very little point having a powerful exhaust fan taking air out of the environment when fresh air is unable to find its way into the environment. In this situation you will overwork the exhaust fan, which can make it noisy and reduce its life span. It is a good idea to have one fan taking air out of the environment and another fan bringing air into the environment.


Unhygienic Practices


Often, beginners don’t understand the importance of hygiene in the grow room. Try to think of it like this: Indoor gardening is half science and half gardening. Unhygienic practices can contribute to the incidence of pathogens and harmful bacterial spores attacking your plants. This means that you need to keep everything as clean as possible.  Dead plant matter left in the grow room,  bacterial build up in the nutrient tank, nutrient exposed to light, debris and/or water on the floor of the grow room and non-sterile equipment are all undesirables. Where possible keep your environment as hygienic as possible.


In between crops sterilise all of your equipment (system, pipes, nutrient tank etc) with an anti-bacterial agent such as Bleach. This way you will minimise the chances of introducing pathogens etc into your next crop.




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