Hydroponics FAQ's

HYDROPONICS

WHAT IS HYDROPONICS?
Hydroponics is method of growing plants without any soil, instead an inert growing media is used to replace the soil and plants are regularly or permanently provided with a nutrient rich solution.


WHAT IS QUICKER, HYDROPONICS OR SOIL?
Hydroponics produces much quicker growth rates and much better yields, compared to soil grown plants. Hydroponics growing media offers a lot more available oxygen to the roots of the plants producing much quicker growth, and hydroponics systems also deliver water and nutrients directly to the roots of the plants, allowing plants to put all their energy into the top growth. This is why a hydroponically grown plant, grown for the same amount of time as a soil grown plant, can be much bigger and better, producing more fruits or flowers.

NUTRIENTS & ADDITIVES

WHAT IS BETTER A ONE OR TWO PART NUTRIENT?
We have used many one part nutrients and also two part nutrients over the years and have to say that both have given good results. Many growers prefer a two part nutrient for hydroponics and also for coco, but for soil most commonly a one part nutrient is used. We would recommend a one part nutrient to a novice grower wishing to try hydroponics and after several attempts of growing with a one part, maybe try a two part to see if your results improve. The main thing is the nutrients that you buy are of a high quality, a good one or two part nutrient can both deliver amazing results.


HOW DO I KNOW IF I HAVE UNDERFED?
The most common sign of underfeediing and a lack of nutrients in a plant, can be the bottom leaves of the plant loosing their vibrant green colour and turning a pale yelllow. This will slowly affect more leaves and slow the growth of the plant. The nutrients supplied in the water will need to be increased and fed more regularly to the plant.


HOW DO I KNOW IF I HAVE OVERFED?
A plant that has been over fertilised will show signs with leaf growth being twisted or curling and the shape of new leaf growth looking irregular, the tips of leaves can also turn brown, dry and fall off. The plant will need flushing with water and a milder nutrient solution applied, until things look better.


WHY USE ADDITIVES?
Additives and boosts can be applied to the water with your nutrients in, and can assist plants in many ways. There are many additives and boosts available and most commonly they are designed to help a plant produce quicker growth and more fruits or flowers. There are also additives designed to assist plants internally and strengthen plant cells, helping to fight against attacks from pests or diseases.


HOW DO I KNOW IF I HAVE HARD OR SOFT WATER?
A hard water area will produce a lot of white scale inside a kettle and a soft water area will produce very little. Some nutrients are available to suit hard or soft water areas, take a look inside your kettle to see if you have hard or soft water before purchasing your nutrients.

VENTILATION

HOW DO I KNOW WHAT SIZE EXTRACTION KIT TO BUY FOR MY GROWROOM?
Air in your growroom should be extracted and replaced at least 20 times per hour. An ACH (air changes per hour) of 20 would mean the air is exchanged every three minutes. In ventilation air movement is measured in cubic metres (m3), so to find out the size of extraction kit required for your growroom you will first need to calculate the cubic metres of air that is in your growroom. This is simply done by measuring the length, width and height of your room in metres. Then multiply the three figures to give you the total size of cubic metres of air in your room. Then you can multiply the total figure by 20 for the ACH, this will give you the figure of air in cubic metres that should be extracted and replaced every hour in your growroom.
Example: Below are the figures for a growroom that is 4 metres long and 3 metres wide and with a ceiling height of 2.5 metres.

4 x 3 x 2.5 metres = 30 m3
30 m3 x 20 ACH = 600 m3

A total of 600 cubic metres per hour would be required for a room this size, but with the addition of components in your growroom emitting heat (light, ballast), we recommend that it is always better to exceed the figure by at least 10% to compensate for this, so our total figure for a room this size would be 660 cubic metres per hour. An extraction kit matching this figure or slightly larger would be required.


WHAT IS BETTER TO USE, ALUMINIUM DUCTING OR INSULATED DUCTING?
Insulated ducting is better to use than aluminium ducting as it helps to greatly reduce the noise levels created by the fans and the air travelling through the ducting, with its acoustic properties.


DO I NEED TO USE A FAN INSIDE MY GROWROOM?
Yes, the movement and circulation of air inside your growroom is also very important. Using an oscillating fan or a wall and floor fan can be very beneficial and will help to replace the air around the plants more easily. The creation of a slight wind inside your growroom will also help to strengthen plant stems, and when flowering or fruiting plants it can help to prevent botrytis (bud rot) from forming. Hot humid conditions with little air movement are a great place for bud rot to thrive.


WHAT HUMIDITY LEVELS DO I NEED IN MY ROOM?
When propagating seedlings or cuttings a humidity level of around 85-95% is required, this can easily be achieved with the use of a propagator. When plants are in the growth stage a humidity level of around 65-75% is required, and when flowering or fruiting plants a humidity level of around 45-55% is required.


WHAT TEMPERATURES SHOULD I KEEP MY GROWROOM AT?
For different plant varieties temperatures can differ, but most commonly the temperature should be between 21-25 degrees Celsius when your grow lights are on and it is the day period for the plants, and for the night period the temperature should drop slightly to about 18-21 degrees Celsius. Too big of a fluctuation with temperatures can result with plants suffering and slow growth. Try to keep a constant regular temperature and your plants will love it.


HOW DO I CONTROL MY FANS TO KEEP THE REQUIRED TEMPERATURES?
The best way to control both the inlet and outlet fans to keep the required temperature is with a unit that has a thermostat and fan speed controller. We stock the Primair fan speed controller unit with thermostat. This unit requires only one plug to a mains supply and it can have two small or large fans connected. The thermostat dial can be set to the required temperature and both fans have an idle speed, which controls the speed of the fan when the temperatures are reached. Basically if you set the temperature to 22 degrees celsius the fans will turn on to full speed if this temperature is exceeded and if the idle speeds are set at 0, the fans will shut down completely when the target temperature is reached. If the idle speeds are set at 50% then the fans will continue to run at 50% RPM when the target temperature is reached. This unit allows total control for room temperatures at the turn of a dial and can help to prevent dramatic temperature fluctuations in your growroom


WHEN MY FANS SHUT DOWN COLD AIR STILL COMES INTO MY GROWROOM THROUGH DUCTING?
This can be a common problem and can easily be solved with the use of a back draft shutter. Back draft shutters are circular with internal hinged doors and can be easily installed into your ducting to prevent air movement when fans are off. When your fans turn on the pull of air will easily open the hinged doors to allow the air to travel through, when your fans turn off the hinged doors will close stopping any air passing in or out of the fitting and keeping your growroom temperatures at a more constant level.


HOW DO I STOP PESTS ENTERING THROUGH MY FRESH AIR SUPPLY DUCTING?
There are filter chambers available that can be fitted into your ducting to prevent anything entering your growroom, or for a cheaper option you can use a pair of stockings to cover the end of the ducting. This will allow air to travel freely but will stop any pests entering, and they can be changed regularly at a very low cost.


I HAVE A LARGE ROOM BUT DONT WANT A BIG CARBON FILTER HANGING FROM MY CEILING?
You don't have to, we recommend to many customers who require large amounts of air to be moved, to use one large fan and two smaller carbon filters to be suspended, instead of one large heavy carbon filter. This allows for one hole to still be used for expelling the air from your growroom. The fan can be situated near to the main outlet hole and connected with ducting. The other side of the fan facing the growroom can have a tee piece to split the ducting into two sections, and the ducting can have damper units fitted to control the flow of air allowed to travel through each line of duct, as air follows the path of least resistance. The damper units can be closed or opened to balance the flow. At the end of each run of duct you can reduce down to suit the smaller carbon filters. This spreads the weight across your ceiling and can also improve your extraction, as it removes hot stale air from two points in your growroom.