The effect of various growth mediums on the development and production of plants in hydroponics systems.
By Ben Safronovitz
In a trial conducted at Camdeboo Farm near Fourways, Johannesburg, South Africa, one basic question was posed. Are there any differences in the overall performance of plants grown in different growing mediums? …The reason for the trial is the general uncertainty (at least in South Africa) regarding growing mediums. Many growers are confused or reluctant to use some mediums due to a lack of experience, lack of performance information, and/or an ignorance regarding the financial implications of using the medium in the short- and long-term.
The main objective of a grower is to invest the minimum possible in infrastructure and achieving the maximum yield, which in financial terms means increased profit. Therefore, in the short-term, investing in an inferior growing medium is a reality. The fact is that a larger initial investment will in the long-run return an increased yield per growing cycle to warrant the investment, and yield a greater profit.
In South Africa sawdust as a hydroponic medium is used extensively; it is inexpensive, readily available from a nearby mill, and due to its low-cost, can be discarded after each growing cycle.
The importance of understanding the characteristics of a growing medium and the long- and short-term affect on the plant is essential to the overall success or failure of a crop, therefore the trial targeted the most commonly used growing mediums in the country, each on its own (to serve as a control batch) and also in combination with other growing mediums. Without elaborating on the physical and chemical differences among the tested growing mediums, each has characteristics, which make it a usable medium – for example: bulk density, porosity, aeration, ability to contact water with high holding capacity, highly hygroscopic, create capillary water and nutrients dynamics, etc.
The mediums used for the purpose of this trial were:
• Palm pith (Coir) 100%
• Perlite 100%
• Vermiculite 100%
• Sawdust 100%
• Palm pith 50% / Perlite 50%
• Palm pith 70% / Perlite 30%
• Palm pith 40% / Perlite 30% / Vermiculite 30%
• Perlite 50% / sawdust 50%
• A locally produced light compost pot soil 50% / Perlite 50%
Growing medium trials at Camdeboo Farm near Fourways, Johannesburg.
A standard tunnel 30m x 10m was selected for the purpose of the trial, positioned north-south with excellent light cover during the day. A white/black ground cover plastic sheet was used to eliminate weed growth and increase light reflection at the tunnel floor level, thus increasing plant photosynthesis.
Day one – seedlings transplanted into medium.
Medium consists of 50% palm pith and 50% Perlite.
Seedlings in 100% sawdust.
Seedlings grown in 50% pot soil and 50% Perlite.
Seedlings grown in 100% Perlite.
Seedlings grown in 100% Vermiculite.
Perlite 50% Sawdust 50%
The trial principles of using one crop (tomato), one cultivar (Malory – indeterminate variety produced by Mayford-Sakata seeds), under the same climatic conditions and nutrient feed and irrigation cycle regime across the various mediums, allowed a fair and unbiased evaluation of the plants’ performance during a complete growing cycle.
The hydroponics method used was quite revolutionary, which is in the process of patent registration. In essence, the method uses growing containers with a slit on one side at a certain level. This method allows routine irrigation (four times daily) of approximately 800 cubic centremetres of water and nutrients per plant on average, which has enormous implications on cost in terms of saving water and nutrients. The growing system was an open system (not re-circulated) and the drain kept to 10% of the total volume.
The floor plan was organised to allow for eight rows of 48 containers each. One block of 48 containers served as a control, representing each of the tested mediums. There were 432 containers with two plants per container, a total of 864 plants. Each medium covered a block of 48 containers situated along the tunnel width to ensure fair distribution of light or shade across the eight rows, eliminating the possibility of false results due to uneven exposure to light.
sir’i wantINTRODUCTIO to NHydroponic Tomato Production and SOILLESS GARDENING plese help me,thanks
im seeking of developing greenhouse and hydroponics technology for variety of crops in Pakistan. we are interested in developing these technologies at commercial level pl
contact me to help you in your hydroponics project I’m expert in this field.
Hi
Please feel free to contact me.
Best Rgds,
Ben
ben111251@gmail.com
[...] Issue 117: Comparing Growing Media [...]
Dear Mr. Safronovitz,
Thank you for this excellent article. As a result of the work of professionals like you, us growers find new hope and direction in striving to improve our products. I was truly impressed by the quality of tomatoes you grew in this experiment and was wondering if I could get some information on other factors involved in the production of these high quality tomatoes. What was your nutrient solution (EC an pH)? what method and regiment of irrigation did you use. What were the environmental parameters present in the course of production? I know you must be quite busy, but I would appreciate some more information on how you achieved these excellent results. Thank you.
Thank you for the information and research. I am from the USA and have a background in Hydroponics. I find myself in Australia on an Aquaculture farm and arboretum, which presently raises a crustacean they call Yabby’s. We would call them Crawdads or crayfish in the USA. They also raise chickens. I would like to integrate an aquaponic system into the operation for the production of food and perhaps ornamental crops. They have a lot of sand here. It is a bit fine. I have not used sand as a medium before or integrated into an aquaculture operation. Do you have advice or recommendations that you could share with me? Thank you
Hi
Sorry did not see your message before.
Please feel free to contact me.
Best Rgds,
Ben
Dear Ben Sir!
Thanks a lot for your infomation given in comparing growing media.
It would be kind of you to get some information related to pest control like white fly, Tomato leaf turn curly(curl upward and form tube),late blight(Fusarium Oxysporum) for number of seed variety available here in Singapore.
We use dripper system to water 4times a days, Liquid nutrient 2.5EC/6-7pH once/week, Use Moss peat for First crop & Coco peat on 2nd crop under poly shed, with all open side wall due to 65-70%RH and ambient temp 22-47Deg C.
Size of Cherry Tomato is 30mm and weight around 20gm with only 2 sucessful truss/plant of 6-7fruit/truss of this determinate variety.
we are just learning to grow in small garden & getting only 15-30% yield due to plant growth severly affected. Not able to see any visible pest other than few number of flying of white flies.
Like your help to perform matrix/do experiment to isolate root cause of low yield.
Thanks & Regards
Pradip
I have lived Arizona, USA, for many years and surrounded by cotton fields. The side of our house was literally coated with white flies. The only safe deterrent is to purchase a sprayer that attaches to a hose. Use a solution of dish soap and water, about one or two teaspoons (5 milliliters) per quart of water and attach the sprayer to the hose and wash you plants off DAILY until the infestation (season) is over. They’re very difficult to safely get rid of. Good Luck.
Dear Sir,
thank you for the information on comparitive study on various medium,its useful for me as i am trying to cultivate on various mediums available near my farm.hope i will be able to acheive better results after reading your article.
kindly publish aother research articles you have expriemented so it will enable small farmers across the world to produce better quqlity vegetables & earn better profits
thanking you
with regards
jayaprakash
Thank you
Hi,thank you very interesting, I am looking at doing some sort of course to kick me of with hydroponics, can you advise of any books/sites etc that will be helpful
regards Russell
Great article Ben, its good to see a well done study on mediums.
regards,
tony
Are the insides of the fruits watery, or, are they well-developed in to flesh, across the various growing mediums tested? This would be an indicator of quality, in addition to sugar (brix) content.
Hi, We are very interesting to supply coco peat grow bags for your tomato growing, see my web http://www.greensubstrates.com
Kapila
Hello! This is my 1st comment here so I just wanted
to give a quick shout out and say I truly enjoy reading through your blog posts.
Can you recommend any other blogs/websites/forums that go over the same topics?
Many thanks!