What is the best material to use for NFT growing channel?
PVC (PolyVinyl Chloride) vs. HDPE (High Density PolyEthylene)

The ‘Green’ movement is gaining momentum and the spirit of the movement has integrity. In my opinion, it is about building a future where the ‘true’ costs of commerce are transparent, where sustainability, though illusive, is a target after which to model our technologies. 

With this in mind, let’s compare these two materials, PVC and HDPE. I look toward reputable organizations who have done their homework regarding environmental costs, manufacturing costs, disposal costs, recycling costs, etc. ALL of the costs incurred to produce and dispose of/recycle a product.

One such organization is the US Green Building Council (USGBC). With 15,000 organizations participating in this ‘green’ movement, here is their mission: To transform the way buildings and communities are designed, built and operated, enabling an environmentally and socially responsible, healthy and prosperous environment that improves the quality of life.* Here’s what they have to say about PVC:

In February 2007, the Technical and Scientific Advisory Committee of the (USGBC) released its report on a PVC avoidance related materials credit for the LEED Green Building Rating system. The report concludes "no single material shows up as the best across all the human health and environmental impact categories, nor as the worst" but that the "risk of dioxin emissions puts PVC consistently among the worst materials for human health impacts."

LEED Rating System is an attempt to provide a credit for avoidance of PVC. In general, there is less environmental concern with ABS (Acrylonitrile butadiene styrene) than PVC, due to the chlorine in PVC and the potential of dioxin production during incineration or accidental fires.

The State of California is currently considering a bill that would ban the use of PVC in consumer packaging due to the threats it poses to human and environmental health, and its effect on the recycling stream.[40] Specifically, the language of the bill analysis[41] stipulates the EPA has listed PVC as a carcinogen. It is also further cites there are concerns about the leaching of phthalates and lead from the PVC packaging.

Every grower who utilizes hydroponics to grow crops must have an EC and pH monitoring device, or meter, to make sure these crucial set points are always in balance with one another.  EC (nutrient strength) and pH (nutrient availability), are two of the Basics of Hydroponics .  As most growers are aware, pH can waver between 5.7 and 6.6 without a problem, though keeping it at 6.0 to 6.3 is optimum. EC is a little trickier. Depending on temperature, humidity and airflow, a couple points in either direction can really affect crop performance. With high temp and high relative humdity, plants have a difficult time transpiring.  They need to keep cool, but cannot easily cool themselves by evaporating water from their leaf surfaces due to the air which is already saturated.

The point here is, most of the time, moderate EC and pH fluctuations are tolerable, except when there are extremes in temperature and relative humidity.  The problem is that meters and dosers have a tendency to work SO WELL and be SO RELIABLE, we forget to make sure they are being honest with us. It's easy for bacterial slime, algae, salts, amendments and more to accumulate on the conductivity probes, as well as the specific gravity bulb in the pH probe. If you are not constantly testing your hand held meters against your dosers to keep the probes honest, you may be in for trouble when you encounter extreme environmental conditions.

Better to make it a habit of cleaning and calibrating probes once a month. Since most growers do not, we recommend, as we head into spring with higher temperatures and relative humidity, please do it now. Make sure all your metering equipment is clean and accurate. Then, when any crop issue comes up that needs your attention, you will know it's not inaccuracies of your testing equipment. Also, replace batteries in your EC Commercial Truncheons and have spares for your pH meters .  If your meters are getting old and are not calibrating easily, invest in new ones. This is a much less expensive solution than risking any crop lost due to something as simple as an inaccurate set point.

Plants are basically electric. That may sound weird, but when you think about it, plants require light (which is a wave or a particle depending on which school of thought you subscribe to), they require CO2 (which are charged molecules of carbon with two oxygens found in the atmosphere that is prominently occupied by nitrogen gas), and they require nutrients at the root zone (which are primarily inorganic elements in the form of ions or 'magnetically charged particles', which is the only form a plant can absorb). These ions must be available in water for the roots to be able to absorb them by osmosis. Where do you begin?

Then the magic of photosynthesis happens, combining them all to produce a living organism true to the genetic code from which it is created. In nature, that process has been occurring for what, a billion years? The only way we can improve upon it is to leave it alone. Organic matter is consumed by microbes in the soil releasing ions that plants require…feed the soil and microbes feed the plant. With hydroponics, we feed the plant directly.

Assuming that light and CO2 are in abundance, with hydroponics we focus on nutrient availability at the root zone. Are the nutrients pure, balanced and available? How do you know? Where do you begin?

The first step to being able to create hydroponic nutrients is to understand the difference between soil nutrients and the requirements of plants. Most gardeners are familiar with soil nutrients such as those called by the numbers 20-20-20, but what does 20-20-20 really mean?

One might assume N.P.K ratio means 20% Nitrogen (N), and 20% Phosphorous (P), and 20% Potassium (K). No, it’s not that simple. It’s 20% Nitrogen (N) and 20% Phosphorous Pentoxide (P2O5) and 20% Di-Potassium Oxide (K2O).  (Depending on the country of origin, these units change by continent.) This translates to the actual % of the N.P.K as follows:  20% Nitrogen (N), 8.8% Phosphorous (P), and 16.6% Potassium (K).

However a good hydroponic nutrient contains all of these plus all the other minerals required for healthy growth. They will also be in the correct ratio to each other, according to plant type, and stage of growth, e.g. vegetative, flowering or fruiting stage.

The minerals required for good growth are as follows:

Macro elements:

• Nitrogen (N)
• Phosphorous (P)
• Potassium (K)
• Calcium (Ca)
• Magnesium (Mg)
• Sulphur (S)

Micro elements:

• Iron (Fe)
• Manganese (Mn)
• Boron (B)
• Copper (Cu)
• Zinc (Zn)
• Molybdenum (Mo)
• Sodium (Na)
• Chloride (Cl)
• Silicon (Si)

There are other minerals found in plant tissue when analyzed, but for our purposes these are the main requirements for hydroponic growing, and the ones we have to monitor.
 
We have over 20 time-tested, custom nutrient formulas for growing plants hydroponically. They are designed to be dissolved in ‘pure’ water. We test  your source water first, then custom formulate if need be. Once we have the  correct formula for your crop and your water, we then test the nutrient  solution AND the plant tissue after the first crop to see exactly what the plants are taking up and what is left in the nutrient solution. If necessary, we then adjust the formula one more time. In most situations, this is enough; in others, we test every 4 months or so just to KNOW that the nutrients are spot on.
 
Any experienced  grower knows that consistent crop production is about isolating the variables and controlling them. With our nutrient  formulas, we make sure they are no longer a variable you need to worry about.  That allows the grower to focus more on environment and moving the crop or produce through the system to markets.
 
All our nutrients are made from the best mineral salts, very pure. They are 2 part powders which means, you will need to dissolve bag A in one tank and bag B in another, stir well and then let settle. Then draw equal parts from both to make a balanced nutrient solution.
 
This is by far the most economical way of buying and providing nutrition to your plants. The healthier your plants, the more complete their nutritive value is when consumed. For most growers, at  some point, you will want to get your bags of raw mineral salts locally. We  supply a Trace Element mix (TE) to which you add your ingredients to our specifications. And it’s custom only to your growing  operation.
 
We recommend that all our commercial growers set up blanket orders to make sure their nutrients are shipped once a month with out  fail. This avoids costly, over-night shipping charges when you forget.  
 
Let us help you make worrying about your plant nutrition a thing of the past. Call and talk with one of our  commercial specialists and get your nutrients dialed.

The Basics of CF (Conductivity Factor)

CF is EC with decimal point removed (e.g. CF 15 = EC 1.5)

The CF test is a measurement of the electrical conductivity of water. Pure water does not conduct electricity, so the CF is 0 (EC 0.0), but as we dissolve mineral salts into the water, the electrical conductivity increases. We can use this to our advantage when growing plants - if the plants remove minerals from the nutrient; the CF reading falls, so we add more minerals. If the plants remove only water from the system, on a hot day for example, we only have to add water, as the CF reading will rise.

We measure the CF level of nutrient solution with a simple conductivity meter that is manufactured for hydroponics with an automatic temperature correction built into the meter. When the temperature of the water changes, the CF reading also changes, so all equipment should have automatic temperature correction to give a temperature-corrected CF reading.

CF is important to plants because a solution that is too strong can burn the roots and causes reverse osmosis (osmosis is the natural process whereby water including dissolved minerals, but not solids, is moved through a semi-permeable membrane, such as the cells in plant roots - the weaker solution flows to the stronger to try and reach equilibrium. This is how plants take in minerals). However, reverse osmosis is when the minerals are drawn out of the plant because the solution on the outside of the plant is stronger than on the inside, this can lead to plant death. A CF level too low will cause weak, thin and leggy plants, and the plant will not produce its potential yield. It will also be more susceptible to disease.

CF levels are different for many crops, even at different stages of growth of the same plant (i.e. lettuces grow at a CF range of 6 to 16).  Levels are generally at the higher end for the hearting types in the cool conditions of winter [cool, low light conditions], and lower in the tropical conditions [hot, high light conditions] for the loose leaf type lettuces. Tomatoes are normally grown at CF levels of 26 to 46, depending on variety and stage of crop. They start at levels as low as 18 at planting and build up the CF level until full fruiting occurs at the higher levels. Home growers with hobby systems will grow good tomatoes at CF levels of 18 to 30, harvesting the fruit vine ripe, while the commercial grower will grow his commercial varieties of tomatoes at the higher CF levels to get better quality into the fruit, as they are often picked before being fully ripe.

Experience will teach you what the CF level should be - the plants will tell you. If the plants are thin and leggy, and providing there is sufficient light, the CF level is too low. If the plants are short, thick and stunted, then the CF level is too high. We can learn from the plants; they will tell us what they want in the type of growth we see.

Basics about pH.

• The pH scale is from 0 to 14.
• pH is the acidity or alkalinity of the nutrient.
• The most important test of a nutrient solution is pH.
• At 0, it’s the most acidic, and at 14 it’s the most alkaline. At 7 it’s neither acid or alkaline, but neutral.

Plants can survive in the pH range 4.0 to 8.0, but below 4 there is a danger of the roots being burnt and some minerals are not available to plants. Above 8.0 some of the minerals can be precipitated or are not available to the plants. The ideal range for most plants is from 5.8 to 6.5, so we try to maintain this pH at all times.

If the pH is outside the range where plants can take up minerals, then it does not matter how good or bad the nutrient is in terms of dissolved minerals, the plants will starve to death as some minerals cannot be taken up by the plant. Deficiencies are often seen in crops grown at the wrong pH even when the mineral balance of the nutrient is perfect.

We measure the pH of a solution with either a pH meter, or a pH liquid vial. The pH meter is calibrated using buffer solutions, and from the pH test reading we either have to raise the pH or lower the pH.

When plants are growing in good light and warm conditions the normal trend is for the pH to rise and we have to add a pH lower (acid solution).

In cool, dark, short day conditions, it can be normal for the pH level to fall and we have to add a pH raise (alkali solution).

To lower the pH we use an acid, phosphoric or nitric. To raise the pH we use an alkali, potassium hydroxide.

Remember to never add any adjuster at full strength. Always dilute any pH adjuster with water by at least 100 to 1, and ideally 1000 to 1. Add small quantities of pH adjusters to the nutrient solution, re-measure the pH and adjust again if necessary. Very small quantities of adjusters are required to move the pH, so do not put in large quantities at one dose.

Fall is here!  With the change of season comes shorter day length (less light), higher humidity, and cooler air in the evenings and night time. Plants have a tendency to stress if you don’t anticipate this and take preventative actions.  With tomatoes, cukes and peppers, the stress shows up as BER (blossom end rot), poor fruit set and mildews, on top of a slow down in production. With lettuce and basil (quick turn crops in NFT), it shows up as weak stems, mildews and slow growth.

For tomatoes, keeping calcium moving in the vascular system in high humidity is crucial for good fruit set as well as vegetative growth for lettuces and basil. AminoActin is designed to do just this! The aggressive amino acids in AminoActin chelate Calcium, keeping it in solution and available to the growing tips, regardless of humidity and transpiration rates. Same with lettuces, basil and other herbs; remember, since Calcium is not a mobile element like Nitrogen, it must be in solution all the time and available to actively growing tissue constantly.

Make sure your HAF fans are causing turbulence in the greenhouse, making it difficult for fungal spores to get comfortable and inhabit tissue. Also, keep your greenhouse spic and span, all cut material and waste OUT of the greenhouse.

If you are taking advantage of off-season vine crop markets, you must have HID lights to keep production up during the short days. For quick turn crops, lighting up your seedling production and nursery area is crucial.  As you well know, mediocre seedlings produce mediocre plants. Holding market share in the Fall/Winter months with quality and consistency is crucial even though your operating costs are higher. We stock HID lighting and have lighting layouts for many different applications. We can even help you with your layout and size your electrical panel.