FAQ

What parts of the mother plant make the best clones?

The best clones come from rapidly growing top or side shoots. Keep these shoots growing rapidly by keeping the mother plant a bit warmer – around 25°C-30°C and a bit more humid – at about 60%. You must keep the mother plant insect and disease free. Poor clones make poor plants.

When can I move clones into the growing room?

cloningWhen you can see new roots coming from the bottom of the cube. If you move them too soon, they may lack enough roots to cope with the stress. If you don’t see roots within 3 weeks of taking the cutting, then the chances are they are having trouble striking roots. Carefully (the roots are quite brittle) pull the rockwool apart and check if the roots are growing. If not and the clones are still in good condition, then they might still form roots. However, if they’ve taken this long then there is obviously a problem with your conditions or the clone material you are using.

I always have trouble striking clones. How can I do it better?

Here are some pointers. Try using only the best clones (see 48). Make sure you’re using a good cloning agent. Make sure your rockwool is always moist and make sure the incubator doesn’t get too hot. Also use Clone Start and Regen-A-Root on the clones for greater success.
What exactly is the difference between a recirculating system and a run to waste system?

A recirculating system is one where the nutrient solution is continuously pumped from a reservoir to the plant and then drains back to the reservoir. The same water is used over and over though the reservoir is occasionally “topped up” to replace the water used by the plant. Flood and drain and NFT (Nutrient Film Technique) are examples. A run to waste system is where the nutrient solution is periodically pumped from the reservoir to the plant then allowed to drain away and is discarded. Growing in cocopeat is an example of a run to waste system.

What is the best medium to use?

There is no best medium. All the media on offer are suitable depending on the system you decide to use. For Recirculating systems you should use an inert medium such as expanded clay, rockwool or perlite. For run to waste systems you may use either an inert or organic medium such as cocopeat. Success with any medium comes down to good management.

See NEW cloning guide for a more detailed explanation of cloning. PLEASE NOTE: If your query was not answered here please contact help@cxhydroponics.net for more help.

What do you mean when you talk about “Hot Mix Technology”?

Hot Mix Technology uses the latest organic and synthetic chemical reactions to create
combined hydroponic nutrient and additive compounds. This could not normally occur from conventional methods and as a result these compounds are much more stable in solution.
Ordinarily, the normal method of nutrient manufacture is to simply dissolve a few chemicals in water. However, Hot Mix Technology forges a complete fused nutrient that is balanced and more reliable under poor conditions. Furthermore, when the plants take up these fused compounds, they release far more energy to the plant than free ions alone. In other words, you will get a lot more from CX Hydroponics, making it excellent value for your money.

Cloning seems to be one of the areas where beginners and experienced growers alike have difficulty from time to time. It needn’t be like this, though, as long as you follow these basic guidelines. Just be aware, however, that plants without roots are fragile and require a perfect environment. To give yourself the greatest chance of success, try following these guidelines. Remember that these are guidelines. The rougher you are then the more clones you will need to take to get the required number of rooted clones. You also need to work quickly so the clones don’t dry out. Start out by taking three times the number of clones you will eventually need. As you get better at it, you can reduce this number.

  • Before you begin, the mother plant from which you will take your clones must be properly conditioned. That is, it should be fed a specialty nutrient such as “Mother Tucker”. This purpose made nutrient ensures that the carbohydrate to nitrogen ratio is correct. Getting this ratio right in the mother plant is a key factor in successful cloning
  • Prior to cutting the clones from the mother plant, gather together everything you are going to use. The time between cutting the clones and inserting them into the cloning medium should be as short as possible.
  • Things you will need are:
    1. Something sharp to cut the clone from the mother plant, e.g., scalpel, knife, secateurs or scissors as seen Fig 1 Whatever you use, it should be SHARP.

      cloningguide11

      Fig. 1

    2. Something to put the cuttings into, e.g.,small pots with potting soil, rockwool cubes (ideal) jiffy pots.
    3. A method of retaining moisture around the clones’ leaves. Commercial growers would use a mist propagation system but for only a few clones you can use a transparent plastic box which lets in the light but can keep the air humid. There are excellent propagation boxes made for just this purpose.
    4. A fluorescent light to provide the necessary low level of light required by the clone while it has no roots.
    5. Either household bleach or hydrogen peroxide for keeping the cutting instruments sterile. You should dip the cutting instrument in this to keep it sterile between cuts.
    6. A rooting hormone. You can use a powder, gel or liquid suitable for softwood cuttings. If the only cutting material you can get is quite hard, then use a cloning gel, powder or liquid suitable for semi hard or semi ripe cuttings.
    7. A stick or something similar to make a hole into which you put the clone. It should be only slightly bigger than the intended diameter of the clone. Rockwool cubes have hole preformed.
    8. Some acidified (pH4.5) for soaking rockwool cubes. These cubes are alkaline so acidic water helps lower the pH. You can make this by putting some pH Down in some tap water. Use a pH meter to test the pH. Research has shown that clones do not make roots as readily at a high pH.

Selecting the clones to use. Ideally, you want growing tips that are about 3-6 inches (100mm-150mm) long.

These growing tips can be laterals, which are small side branches, which you can pull off the main branch see Fig 2.

You can also use other material, such as branches cut into several pieces. Each cutting needs to have at least two leaf pairs along the cutting. Remove the lower pair of leaves to expose the node and leave at least one pair of leaves at the top.

To select the point where you cut the clone from the branch of the mother plant, gently bend the selected branch between your thumb and forefinger. As it bends, try to select the point where there is the start of resistance to bending.

That is, it bends but not easily. If it bends easily without resistance it is too soft Fig 3, if it doesn’t bend much or breaks it’s too hard Fig 4.

Cut the clone at the point of resistance to bending with a very sharp instrument.
Now prepare the clone by trimming off ½ to 2/3 of the leaves.

If you have pulled a lateral off a main branch, you may have ended with a heel at the end of the clone see Fig 7 . This is part of the bark of the branch you have just pulled it off. Do not cut the entire heel off, just trim this back to very close to the stem. Your clone should now look something like Fig 6.

You can see the untrimmed heel at the end of the clone before trimming.

I see recommendations talking about E.C., Cf, and ppm. What are they and what is the difference between them?

In hydroponics, they are all measurements of the amount of dissolved salts in your nutrient
solution. These measurements include all salts, whether fertilizer salts or non-nutrient salts already
in the water such as common salt. These salts are commonly referred to as the ‘background conductivity’ of your water and can be measured using a conductivity meter (see 11).

E.C. stands for Electrical Conductivity, Cf stands for Conductivity factor and ppm stands for Parts per Million. For reference, 1.0 unit E.C. equals 10 Cf units which equals approx. 725ppm. Refer to Fig1.
As different chemical salts produce different conductivities, the conversion will depend on the actual combination which varies from chemical to chemical. The table below is representative and is accurate enough to be used effectively.

Fig 1. Conductivity conversion table

Conductivity Table

What conductivity levels should I maintain?
This is dependent on the growing method, environment, strain, climate and nutrient. Here are some general guidelines.

Vegetative:

E.C. 1.6 – 2.2
Cf 16 – 22
ppm 1150 – 1600

Flowering:

E.C. 1.8 – 2.4
Cf 18 – 24
ppm 1300 – 1750
You should follow the instructions on the product label. However, if you keep to the middle of these ranges you shouldn’t go far wrong. With a bit more experience you can experiment and come up with what suits your situation best.

What will happen if my conductivity is too high?

Typical symptoms of E.C. being too high.

Your plant’s growth will slow down and if the conductivity is way too high the edges of the leaves will start to burn. Your plants will lose production because the plants will try to conserve water by reducing their growth rate in order to survive. In serious cases of over fertilizing, you will eventually burn the roots and the plants could die. If the conductivity is raised suddenly to a high level from a much lower one then water can be drawn from the plant roots leading to severe root damage

What will happen if my E.C. is too low?

The plants will be pale and stretched. They will starve and the quality of the produce will be poor. If you drop the conductivity suddenly from a much higher level to a low level you can damage the roots and stems of the plants as water pressure in the plant increases.

What is a conductivity meter and do I really need to use one?

This is an accurate electronic measuring tool for measuring the electrical conductivity of a solution. It works by applying a voltage between two or more electrodes submersed in the solution. The meter then monitors how much current is passing between the
electrodes as a gauge of how many ions are in the solution. Be aware that meters may give readings in E.C., C.f. or ppm and some meters may do all three. You really should use a conductivity meter to make up your nutrient solution (see 18). Your retailer will stock conductivity meters and we recommend that you read the instructions before use. It is possible to grow without using one but it is more of a hit and miss affair.

I’ve heard about Fusion Nutrition. What is it?

Fusion Nutrition has been a recent breakthrough of scientific fertilizing research.
Up until now it has been virtually a secret, reserved only for selected laboratories and privileged scientists. Now the secret is yours.
Fusion Nutrition is the fusing of organic practices with synthetic fertilizers to create a nutritional growing system that combines the best of both approaches.
This powerful combination lifts performance to a higher level than could ever be attained by using either pure organic nutrients or synthetic fertilizers alone. Fusion Nutrition has been made possible by the process of Hot Mix Technology. This is the new frontier in fertilizing and its popularity is shown in its swift adoption by commercial growers worldwide.

What temperatures should I maintain?

The ideal air temperatures within the grow room are between 24°C – 28°C during the light hours. Try not to exceed 32°C during this light period and do not go below 18°C as a minimum for the dark period. It is important to let the temperature be higher during the light period and cooler during the dark. Also the nutrient solution should be kept warm in winter, if necessary, by heating the water to between 18°C and 21°C. Any warmer than this and you will begin to deprive the plant roots of essential oxygen as warm water can hold less oxygen than cooler water. Practically speaking, nutrient solution temperatures can get higher than this and up to about 28°C in recirculating systems should be ok provided there is plenty of aeration.

What happens if the temperatures are sometimes too high or low?

As long as it doesn’t happen regularly then no harm should be done. Usually, if the plants are consistently too hot or cold then aside from disease related problems, there will be a reduction in yield. The longer the plant is at the wrong temperature the greater the loss of production.

What humidity should I maintain?

The ideal is 50% in the plant canopy, any higher and your plants run the risk of diseases such as grey mould (see 40). If the humidity is considerably higher than the outside humidity then you probably haven’t got enough ventilation (see 34). To measure humidity you can use a small electronic weather station or hygrometer. If your retailer doesn’t carry them they should be available from most major specialist electronic retailers.

How much ventilation do I need?

growingenvironment11-300x196

Fans vary in size and type. You should ask your retailer for the best fan for your system.

The right amount of ventilation will vary for every situation, however there are some guidelines you can follow. The ventilation should be sufficient in capacity to keep the room temperature no higher than the outside temperature and the humidity at 50%. Too much ventilation may cause humidity or temperature to be too low; too little ventilation and the humidity and temperature may rise to unacceptable levels. It is important that you also avoid a laminar flow. This is where the air is dragged or blown in one hole and sucked or blown straight out another without passing through the plants. This results in a streamlined airflow which does little. The air should pass through the plant canopy to the extent that you can see the leaves moving as they would in a gentle breeze. An oscillating fan inside the grow room will help with this.

 

What do you mean when you talk about “Hot Mix Technology”?

Hot Mix Technology uses the latest organic and synthetic chemical reactions to create combined hydroponic nutrient and additive compounds.
This could not normally occur from conventional methods and as a result these compounds are much more stable in solution.
Ordinarily, the normal method of nutrient manufacture is to simply dissolve a few chemicals in water. However, Hot Mix Technology forges a complete fused nutrient that is balanced and more reliable under poor conditions. Furthermore, when the plants take up these fused compounds, they release far more energy to the plant than free ions alone. In other words, you will get a lot more from CX Hydroponics, making it excellent value for your money.

What is Induced Acquired Resistance?

Induced Acquired Resistance is the strategy pioneered in the hydroponics industry by CX Hydroponics. In Induced Acquired Resistance we stimulate the plant’s own immune system to fight off and prevent diseases rather than relying on toxic pesticides and harsh chemicals.

How much light should I use?

This will predominantly depend on the size of your grow room. As a general guide, use about 600 to 1000 watts per square meter of growing area. Rule of thumb is 1% increase in light = 1% increase in growth up to the light saturation point. The light saturation point is the point where more light won’t get a growth response. Because of heat problems, you are unlikely to reach this point with normal artificial HID lighting. For more information please see your retailer.

What is the best light to use, High Pressure Sodium or Metal Halide?

In our controlled trials, we found that High Pressure Sodium (versus Metal Halide) when used for an entire crop cycle, slightly but noticeably out performed Metal Halide. We have also found that High Pressure Sodium gives a marginally better yield if it used for the bloom phase and the Metal Halide performs slightly better during growth. Our results would not justify purchasing both the lights for growth and bloom but this may not be the case with all species and strains. We also found that both types of lights used together yielded better results than either type alone. Given the choice between the two, we would recommend High Pressure Sodium over Metal Halide.

How high above the plants should the light be?

Using height adjustable lights, you should keep the light between one to two feet (300mm-600mm) away from the tops of the plants; closer for smaller wattage and further for stronger lights.

Another way to gauge correct height is to place your hand on top of the canopy. If you feel too much heat then it’s too close. Too close will burn the tops of the plants and too far will slow the growth down and cause the plants to stretch.

How can I tell if there is too much light?

Lighting in a Commercial Greenhouse

Yield will be reduced because the upper canopy of the plant will get too hot and burn. It will cause the running temperature to be higher than necessary and in extreme cases the plant will “shut down” and stop growing as it will be unable to cool itself down (see 24 and 26). Excessive heat rather than too much light is more likely to be a problem when using artificial lighting.

How can I tell if there is not enough light?

Your yield will not reach its full potential. The plants need light too so the leaves can manufacture sugars for the plant’s use. A rule of thumb is 1% reduction in light from optimal = 1% reduction in yield. In severe cases of light deprivation, the plants will be pale and thin and will be stretching toward the light (see 24).

 

 

I have plenty of light but my plants are still stretching and growing during the flowering period.

This could be caused by excessively long light durations during the flowering period. You could try dropping the light time to ten hours, crank the conductivity up to about 2.6-2.8 E.C. and use a high potash additive such as Superior Potash. Many growers open their rooms during the dark period, allowing extra light in. If the room is not adequately sealed against light then there could be light inadvertently seeping into the room during the dark time. Any light during the dark time may cause the plants to stretch. If these are not your problems, then it could be the strain you are using or too high a nitrogen level during the flowering phase.

Do I need reflective walls inside the box?

Well managed growing environments allow for good crop production.

You don’t need to have reflective walls but reflective walls dramatically increase the light efficiency and therefore plant growth. Non reflective surfaces absorb light which is therefore not available to the plant. Rule of thumb is 1% increase in light = 1% increase in growth up to the light saturation point. The light saturation point is the point where more light won’t get a growth response. Because of heat problems, you are unlikely to reach this point with normal HID lights. Silver or white reflective surfaces are the best to use.

What size reservoir should I have?

For recirculating systems 40 liters/m2 of growing area is the minimum for ease of use. A larger reservoir gives a greater buffering capacity against changes in conductivity, pH and plant water use. You should aim to have the largest reservoir you can comfortably fit in the area you have allocated for one. For a run to waste system, any convenient amount is ok.

How do I make up a nutrient solution?

As a general rule of thumb, you add your nutrient first then add the additives until you reach the desired conductivity (see 8).

Lettuce Grown Using Typical CX Hydroponics Program

Remember, regardless of your background conductivity (see 4) you should still make your nutrient solution conductivity to the recommended level on the label of the product you’re using. In other words, the background conductivity is included in the final conductivity reading of your nutrient solution. For example, if your background conductivity is E.C. 1.0 and the product recommends you have your nutrient solution at E.C. 1.8 you only add enough product till you get a reading of E.C. 1.8 (not 1.0 plus 1.8 to get 2.8) in your nutrient solution. This is an important factor in your growing because if your background conductivity is too high, by the time you add the additives, your E.C. could be too high to add any nutrient. In that case you will need to source better water (see 4).

How often should I check my nutrient solution?

You should check your nutrient solution’s reservoir level, conductivity (see 8) and pH (see 13) at least every second day given that you have an adequate reservoir (see 17) as long as you’re not running high temperatures and you have good water. The more often the nutrient solution is checked the better the chances of preventing serious problems.

How often should I change the nutrient solution?

This will depend on the quality of your water, the size of your reservoir and the size of the plants. You will need to change your water more often if

  1. your reservoir is small;
  2. your water source is poor quality;
  3. your plants are large.

Assuming you have an adequate reservoir (see 17) and good water (see 4), a change every two or three weeks is acceptable when the plants are less than three weeks old. As they get bigger, a weekly change is recommended. If you are unsure of the water quality or required reservoir size, your retailer can help. Of course, this recommendation only applies to typical recirculating systems.

What temperature should my nutrient solution be?

The best temperature is between 17°C and 21°C. Any lower and growth will slow down and any higher and you will start to deprive the solution of oxygen. During summer, it is sometimes difficult to keep temperatures low enough. Generally, you will need to aerate the solution if the water temperature gets too high. The absolute maximum solution temperature is 32°C. Above this and the plant will begin to suffer. During winter, in most places, heating the solution is necessary.

Is it a good idea to aerate the solution?

Yes, especially when solution temperatures start to rise during the warmer months as warm water can’t retain as much dissolved oxygen as cool water. Ask your retailer for aerating equipment.

How much nutrient solution should I give my plants?

This is a good sized reservoir for the system shown here.

To answer this accurately depends on too many variables such as temperature, humidity, medium used, preferred E.C., water source, lighting and plant size to name a few. Most pre-made kits have been designed to water plants correctly, so you would only need to work this out if you were designing your own. Basically, the requirement is to keep the roots moist and aerated all the time but do not over water them, as this will deprive the roots of oxygen. For more information please see your retailer.

I have webbing all over the tops of my plants and what looks like tiny insects crawling on it. What is it?

Severe aphid infestation.

This is a serious pest known as Spider Mite or Two Spotted Mite. Lots of webbing indicates an advanced stage of infestation. Other earlier symptoms of this pest are speckled or scorched leaves. They are small mobile mites like grains of sand that vary in color from red to brown or may be light brown with two dark spots. Mites tend to congregate under the leaves and around the tops of the stems. They are more commonly a problem in the warmer months but may pose a threat at any time. If left untreated, Spider Mites will destroy your plants.

What are aphids and what do they look like?

Aphids are small soft bodied green or black insects usually found clustered along the upper part of the stems and on the leaves. Although not quite as serious as Spider Mites, Aphids can still destroy your crop if left untreated.

What are small black flies crawling around the top of the pots. Are they harmful?

Yes. They are known as Sciarid Fly or Fungus gnats. The young insects in their larval stage attack the roots of your plants. The larvae are approximately half a millimetre long maggots with clear white or yellowish bodies and black heads. Sciarid fly will not usually kill your plants but heavy infestations will severely stunt them, reducing yield and quality. They can also carry and spread the root disease Pythium which is a far more serious problem (see 40). Ask your retailer for a remedy.

What are the white powdery spots on the leaves?

This is probably a disease called Powdery Mildew. Unfortunately, Powdery Mildew is a fungus that spreads by airborne spores that can enter your box through the ventilation or when you open the door. To prevent it, keep your humidity at an acceptable level (see 33) and remove dead leaves. If left untreated, powdery Mildew will consume your crop. See your retailer for a suitable remedy.

There seems to be grey mould on my plants. What should I do?

This is a fungal disease called Botrytis or Grey Mould. It grows under conditions of very high humidity. To prevent further attacks increase ventilation and/or have a fan blowing over the flowers. Unfortunately mould grows easily in crops with heavy flowers and if left untreated, mould can virtually consume your crop.

The roots of my plants have gone brown. Is this normal?

No. You probably have a serious root disease called Pythium. Symptoms of this are browning and softening of the roots, dead feeder roots and lesions on larger roots. Advanced infections cause the plant to wilt and eventually die. Pythium is known as a water mould and as you might guess, it thrives in wet situations. Hydroponic systems suit Pythium well and if your plant’s roots are stressed through poor oxygenation or attack by sciarid fly, then you can expect Pythium to be a problem. The source of infection from Pythium can be your water, extraneous dirt in the system, infected planting material, dust etc. In fact, it can be found almost everywhere. Poorly aerated water with poor drainage is why Pythium is a common and widespread problem in hydroponics. If left untreated you will lose your entire crop.

What could be causing my plants to wilt?

This could be due to high temperature, lack of nutrient solution (see 17), E.C. too high a conductivity (see 8) or Pythium (see 40) to name a few. Start by checking the roots for abnormalities; check your E.C.; check the ventilation; check the temperatures (see 31) of the grow room and the nutrient solution. Try making sure you have adequate ventilation and nutrient solution supply. Excessive heat will also encourage wilting.

My plants leaves are turning yellow from the bottom of the plant. What should I do?

This is often normal near the end of a plant’s life. It is usually caused by the lower leaves being shaded. The plant removes the nutrients from the leaves for use elsewhere causing them to turn yellow. As a precaution, however, check the root system for disease and the solution temperature is correct and remove the yellow leaves. If it is a young plant it could be a nutrient deficiency – change the solution. Use Mighty Grow for enhanced chlorophyll production and vegetative performance.

My plant’s leaves are going brown throughout the plant. What can I do?

There is nothing you can do for leaves already turned brown. Brown leaves are dead leaves. If the brown leaves seem scattered throughout the plant then it could be an insect or mite infestation. If whole plants or whole sides of plants are dying then it will most likely be a problem within the roots. If the leaves are going brown in the upper canopy it could be that the lights are too close. Also check for mites. Next crop, ensure you have the basics right and keep an eye open for pests and diseases.

I have noticed that the leaves are suddenly all going curly. What does this mean?

Check the undersides of the leaves for aphids. Also check for thrips which are tiny (1mm) elongated, black or brown rapidly moving insects. It could also be a problem known as Broad Mite. These mites are invisible to the naked eye. If the problem gets bad enough to cause your plants to stop growing then Broad Mite is probably the cause. You will have to discard your plants. Check the origin of your clones. The infestation probably (but not necessarily) started there.

The tips of my leaves are going brown. What can I do?

This is a stress condition usually caused by the conductivity being too high, the humidity being too low, conditions being too hot or lights too close. In some circumstances it can also be a potassium deficiency or boron toxicity. Change your solution as a precaution.

My plant is going yellow all over. What should I do?

First check that the roots are healthy. If they are then it could be a trace element deficiency or even a total deficiency in the amount of nutrient being given. Check the pH also. Too high a pH will often cause trace element deficiency and consequent leaf yellowing.

I have floaters or scum in the reservoir. What should I do?

The floaters are often fungal or bacterial colonies and don’t usually pose a problem unless they start to block hoses and nozzles. If it becomes a problem then flush your system with a heavy dose of chlorine AFTER THE CROP IS FINISHED. Be sure to flush the chlorine out properly before using the system again. NOTE: Chlorine is poisonous to plants.

What should the E.C. and pH be of my drainage water from a run to waste system?

Generally, you would want the output E.C. to be about 0.1 - 0.5 (200ppm/3Cf) higher than the input E.C. For example, if your input conductivity is E.C.2.0 then the water draining from the pot should be around 2.1 – 2.5 E.C. If output E.C. is higher than the input by >0.5 higher you will need longer irrigation times, if the output E.C. is the same or lower than the input E.C then shorten the irrigation times. These rules only really apply as the plants gets bigger (maybe 3-4 weeks old) and
start to use significant amounts of nutrients and water. Note that with smaller plants the drainage will tend to have a conductivity similar to the input. With the pH, try to maintain the average between 5.5 and 6.5. For example, if your output pH is 6.0 and input is 5.8 then the average is 5.9. You will have to adjust your input pH in order to get the desired output if your pH is outside the desired range.

What should the pH of the nutrient solution be?

Ideally, the pH should be maintained at 6.0 as at this point, a drift of half a pH point down to 5.5 or up to 6.5 is entirely acceptable. It will fluctuate (see 14 and 15), so maintaining the pH between 5 and 6.8 is fine. A short time a bit outside of this range should not cause any real problems but try to keep it within the recommended levels as much as possible. When the pH is outside the recommended range the plant will not be able to take up certain vital nutrients and therefore the growth will slow and in severe cases the plant will starve.

Why does the pH of my nutrient solution go UP?

Assuming your system is set up correctly, this is normal and desirable in the vegetative period. It means that the plants are growing strongly, as they should be.

Citrus leaves showing signs of Manganese deficiency, this is caused by pH being too high or nutrient imbalance

If it occurs later than about four weeks into the bloom period it may mean that nitrogen levels are too high. Another cause of dramatic fluctuation of the pH is the reservoir being too small to cope with normal pH fluctuation. (see 13)

Why does the pH of my nutrient solution go DOWN?

Assuming your system is set up correctly, this will often occur
in the bloom phase as the plants take up nutrients in different
ratios. Normally, the pH drop is not as large as the pH rise in
the growth phase. If it does drop significantly it could be root
diseases attacking your plants or an undersized reservoir.
Always check your roots for disease.

What is a pH meter and do I need one?

A pH meter is a small electronic device that is used to accurately measure the pH of a solution. It works by a glass probe detecting the tiny voltage produced when the hydrogen ion in solution makes contact with the glass probe.

Citrus leaves displaying typical Iron deficiency symptoms as seen here by yellow leaves. This is due to pH being too high or nutrient imbalance.

The more hydrogen in solution the more acidic the solution is. The meter will give a reading of a whole number followed by one or more decimals, 0.0-6.9 is acidic, 7.0 is neutral and 7.1 -14.0 is alkaline. It is very important to maintain the correct pH levels (see 13). Colormetric pH measuring kits are also available but not as accurate. As all meters are inclined to drift, they become inaccurate over time. They need to be calibrated regularly.

What exactly is the difference between a recirculating system and a run to waste system?

A recirculating system is one where the nutrient solution is continuously pumped from a reservoir to the plant and then drains back to the reservoir. The same water is used over and over though the reservoir is occasionally “topped up” to replace the water used by the plant. Flood and drain and NFT (Nutrient Film Technique) are examples. A run to waste system is where the nutrient solution is periodically pumped from the reservoir to the plant then allowed to drain away and is discarded. Growing in cocopeat is an example of a run to waste system.

What is the best medium to use?

There is no best medium. All the media on offer are suitable depending on the system you decide to use. For Recirculating systems you should use an inert medium such as expanded clay, rockwool or perlite. For run to waste systems you may use either an inert or organic medium such as cocopeat. Success with any medium comes down to good management. See NEW cloning guide for a more detailed explanation of cloning. PLEASE NOTE: If your query was not answered here please contact help@cxhydroponics.net for more help.

See NEW cloning guide for a more detailed explanation of cloning. PLEASE NOTE: If your query was not answered here please contact help@cxhydroponics.net for more help.

What is background conductivity and what is good water?

The best water is the purest water, one with the lowest amount of unwanted salts and other contaminants. Background conductivity is the measure of conductivity of the water before anything is added. The ‘background conductivity’ of your water is measured in the same way you would measure a nutrient solution. Rain, desalinated or R.O. water and distilled water are all excellent as they have a very low background conductivity. Tap water can vary from excellent to unsuitable. Generally, the best results will be with water where the background conductivity is below 150ppm. The maximum acceptable background conductivity should not exceed 350ppm (see Fig 1).

300 grams of Salt - If salt is the only contaminant then this much salt will pass through an average system in just 8 weeks from a background E.C. of 0.4.

The higher the background conductivity reading the less room there will be for the nutrient and additives (see 18). Some areas are known to have hard water (see 5 and 6). The bottom line is you should get the best water possible. Better results ALWAYS come from better water, everything else being equal

I have been told my area has hard water. What does that mean?

Hard water is generally considered to be water that contains more than 60ppm dissolved calcium and magnesium. The problem with hard water is that it also contains many other different types of contaminants in amounts which vary greatly depending on the water source. The ratio of calcium to magnesium also varies from one location to another. Even within a single city you may find large variations as cities often have more than one water source. It is for this reason that there is no one nutrient that can compensate for hard water in all areas. While both calcium and magnesium elements are the most common in hard water (they are also plant nutrient elements), if there is too much of these elements, the nutrient solution will be out of balance which can lead to serious deficiencies. The other problem is hard water usually has a high pH and a heavy load of bicarbonates that causes another problem, pH control. For example, in run to waste, some very hard water may require an input pH 4.0 and may run off at pH 8.0 giving an average of pH 6.0. At these levels you are going to require a lot of acid. In addition, the nutrient solution may become unbalanced because of the amount and type of acid used. The best way to solve this problem is to get better water where possible (see 4).

Is soft water always good water?

No. Soft water by definition does not contain significant amounts of Calcium and Magnesium salts but it may contain detrimental amounts (> 350ppm) of Sodium Chloride and still be soft. Soft water is definitely easier to use than hard water provided the unwanted salt levels are not too high (see 4). The main advantage of using soft water is that it is easier for managing pH (see 13 and 5).