Sunday, May 2, 2010

pH Testing in Hydroponics Explained

pH Testing invokes this image of a mad horticulturalist muttering an arcane ritual over a set of vials when nothing could be further from the truth. pH testing is simple and easy to understand.

First off – what is pH? It stands for the rather cumbersome potentiometric hydrogen ion concentration. Simply put, it is a measure of the acidity or alkalinity of a solution. The pH scale is from 0-14 and pure water has a neutral pH of 7. Anything that would be considered acidic is rated lower than 7 and anything considered alkaline is rated higher than 7. Pretty simple.

How does this affect my hydroponic system and why test for pH? Well, different plants require different pH to get optimal growth. Testing your growing solution allows you to correct any imbalances in allowing you to grow bigger and better plants. It is one of the simplest and least technical ways to increase your produce yields and plant size. Think of it as part of providing the best home for the roots of your plants – allowing them to feed at the best rate possible. Always add the nutrients to the water before checking and adjusting the pH of your solution. Should your pH level go too high or too low the nutrients in your system will settle out – leading to deficiency and death.

The simplest and least expensive way to test water pH is paper test strips. The strips, which have a pH sensitive dye on them, change colour when dipped into your nutrient solution. You compare the colour on the strip to a colour chart to determine the Ph level. Nothing complicated about that. The only down side is that the strips can be hard to read because the colour differences can be subtle.

The most popular method to check pH is liquid test kits. The liquid test kits work by adding a few drops of pH sensitive dye to a small amount of the nutrient solution your hydroponic system uses and comparing the colour with a colour chart. These kits are a bit more expensive than the paper strip tests but are much easier to read and are extremely accurate and reliable.

For the technologically gifted, the most high-tech way to check pH is to use the digital meters. They come in a huge array of sizes and prices. The digital pen style meter is the most popular. Just simply dip the electrode into the nutrient solution for a few moments and the pH value is displayed on an LCD screen. They are very handy and easy to use. Digital meters usually need to be calibrated frequently, as the meters can drift and you must check the calibration often to insure accuracy. Most pens also require the tips to be stored in a buffer or electrode storage solution and have a reputation of breaking down without warning.

The major requirement of pH testing asks you to be able to compare colours – making the pH of nutrient solution component of your hydroponic system easy for you to understand and maintain. No mad horticulturalist and certainly no arcane rituals needed.

Saturday, May 1, 2010

The Importance of Ventilation in Hydroponics

Fresh air is at the centre of successful indoor gardening. Outside, air is abundant and almost always fresh. C02 levels in the air over a field of rapidly growing vegetation will vary on how still the air is. Being outdoors, and subject to the warming and cooling of the day, the wind blows in fresh air. Rain will cleanse the air of dust and pollutants.

The outdoor environment is always moving. Plants grown indoors do not have the natural balance that is present out of doors and must be achieved indoors by way of fresh air ventilation or CO2 enrichment.

So you have decided to add CO2 to your hydroponic systems. Great! Welcome to the wonderful world of bigger yields. Now having said that, there is a caveat – like all good things – there can be some events to watch out for. For our purposes we will be dealing with the increases of humidity in a CO2 enriched environment.

Now what is humidity? Simply put – humidity is the water vapor present in the air.

There are various devices used to measure and regulate humidity called psychrometers or hygrometers. You can regulate the humidity of a room with humidistat a variety of tools in your growing arsenal. These are comparable a thermometer and thermostat for temperature control. You can find from most retail outlets combination hygrometer/thermometer unit – we recommend looking for a quality wireless unit for ease of placement.

The humidity level should be in the range of 40-75% when your lights are on which can be measured with a hygrometer. Now the warmer the air, the more retained water- this means humidity levels can easily go beyond the recommended 40-75%. High humidity like this coupled with lower nighttime temperatures (a requirement to get plants like orchids to bloom) can cause condensation to form on leaves. Which means your hydroponic system would be a prime candidate for all sorts of fungus issues, like powdery mildew. Inadequate ventilation is the primary cause of most fungal diseases.

How do you prevent this?

Ventilation fans – both intake and outtake- help regulate temperature, CO2 levels and relative humidity. During the winter months, you're more likely to need a ventilation fan for dehumidification rather than reducing temperature. Air is not exchanged as frequently in winter, so plants naturally raise humidity without air being exhausted. Fans at too high a setting combined with high heat can lead to lower humidity levels as well – find the balance for your hydroponic system and it will take care of itself.


These remove heat, which accumulates rapidly in indoor growing situations. Excess heat can result in excess humidity as the air retains for water. By pulling air in the side of the blower and pumping it out the front. For mounting on a wall or inside a grow box units have a flange on the front. Some feature a round inlet flange for connecting ducting so you can pull air from another room.

Keep fresh air flowing, and watch your indoor garden grow!

Friday, April 30, 2010

Hydroponics in the Home for Seniors

Imagine being retired. No daily grind of the 9 to 5. Now imagine being in a retirement home. Do you have images of a regimented, somewhat institutional environment? Now imagine being in that type setting growing strawberries or roses or fresh herbs? Seems impossible or contradictory? It is entirely possible with Hydroponic Gardening.

Thinking of Elder Care and the quality of life in those years which we common refer to as the Golden Years, you cannot overlook the importance of the value of continued self reliance. These are people, just like you, who for the vast majority of their lives have made decisions regarding day to day activities placed in an environment where this capacity is limited.

Hydroponic gardening allows for personal choice and decision making. As studies have shown, it can be a tool to assist the improvement of the quality of life as well as the immediate environment. The Eden Care program is a great example of this. For the maintaining of self reliance and mental functioning, this method of gardening cannot be dismissed. Being able to pour over seed and equipment catalogues and dreaming of the results is not just limited to the younger mind.

Imagine being able to grow fresh food for your enjoyment, flowers for your pleasure and the tinkering involved with the minimal maintenance and the planning for the improvement of hydroponic systems. Starting small with container growing – such as herbs in a window and then more complex systems as the understanding of what is possible happens. As hydroponic systems do not require bare earth, but can be set up and maintained in just about any extra space- with or without natural light, it seems a perfect match of form and function to re-involve those inhabiting institutions with the natural world.

The capabilities of the style of gardening can be tailored to any scale or environment- from something as small as a cup to as large a scale as a greenhouse making decidedly urban environments where space it at a premium a non-issue. The placement can be adjusted to the height and range of movement capabilities of anyone. Hydroponic gardening is also not limited by seasonal requirements- you can grow all year round. These hydroponic systems can be made from recycled material or purchased from reputable suppliers all depending on the complexity and scale of what hydroponic system you choose to develop. The choice is yours.

There is an almost infinite combination of styles and methodologies regarding hydroponic systems that can be used in such institutional settings. In our opinion, the benefits of such practices are beyond measure. Many universities and horticultural organizations have in depth and detailed information available for you. These sources of information are available online or from your local libraries. Explore, discover and learn – after all - retirement living is all about living first.

Thursday, April 29, 2010

Hydroponic Systems - No Soil? No Problem!

What makes hydroponic systems different from traditional in-ground gardening is a soil-less growing medium. No dirt! All plants require support, to be held up. This basic requirement is dealt with by soil-less growing mediums which are inert, mostly non-organic materials. Non- organic refers to the medium not being derived from living organisms (unlike soil- which is). There is a perplexing jumble of growing mediums available. Generally speaking, these mediums are porous, light, and coarse, allowing oxygen and nutrients easy access to the plants roots. Some of the most common are:

Coconut coir

This is produced from the husk that surrounds the coconut shell. Made up of millions of tiny micro-sponges, it can absorb and hold up to eight times its weight in water. It lasting three times as long as peat moss so is fairly sturdy. It is also called palm peat, coco, or just coir. Some of the advantages are better water retention and aeration. The disadvantages of coconut coir are its breakdown after several uses and some drainage issues. It is often mixed with other media to improve drainage in hydroponic systems.

L.E.C.A / Lightweight Expanded Clay Aggregate

This is clay which has been heated under high temperatures until it puffs up. It makes a very coarse medium as the clay balls are about 1/4" across. Superb drainage, holds moisture, stays put and is reusable after sterilization are just some of the advantages of this medium. On the downside it doesn’t hold moisture as well as mediums like coconut coir and can be more costly.


Glass flakes (Silica) are heated until it expands producing what we know as perlite. These tiny nodules hold water well and provide drainage. A common medium due to its low density (have you ever picked up a large bag of Perlite – it weighs almost nothing) and somewhat low cost. Its advantages are its reusability and low cost, not to mentioning it’s lightweight. That being said it cannot be used alone for ebb & flow hydroponic systems, it will float away or move during flooding cycles.


Fibers spun from melted Basaltic rock. A binder is added to the fibers and they are compressed and cured into large slabs. The density of this growing medium can be adjusted by changes in the amount of pressure during production. Large slabs are cut into smaller slabs and propagation blocks for easy handling. Advantages of this medium are the ease of handling, convenience, better control over nutrition, being able to plant seeds in it and allow the plants to be very stable. The drawbacks are that all rockwool is not the same. Some are produced from slag left over from smelting operations and as such have a high proportion of metals which can be somewhat reactive with your nutrient solutions. Rockwool can also have mineral oils present and may contain wetting agents used to counteract this that will wash out over time.

Much more information regarding these mediums is available from other sources, this basic summary of common growing mediums used by hydroponic systems touches lightly on the subject. Vive la difference!

Check out more information about hydroponics systems or in home gardens at my website. It's a site dedicated to hydroponics