Every living creature needs energy to live, develop and grow. For most living creatures the most important energy source is sugar (glucose). Green plants are the only ones capable of producing these sugars themselves. These sugars are produced from water, which is being absorbed through the roots and carbon dioxide, which is being absorbed from the air. In order to make sugar out of these matters, the plant needs light. This process takes place in the green pigment, (chloroplasts) and is called; photo synthesis. (photo=light, synthesis=produce, therefore photo synthesis means; produce through light).

As above, the plant needs light for its energy supply. Because we are talking about growing indoors, we will have to supply a light source. Normal lamps are less suitable for the job. A plant needs light of certain wavelengths, which are not or not present or strong enough in normal lamps. The Highlife Co. recommends the use of type SON T lamps. They are suitable for both the growth stage, as well as the flowering stage. Ballast's are necessary for these lamps. Ballast's of 600 watts have the most favourable output of delivered light per watt. Depending on the variety we recommend to use between 400 and 800 watts per m2. With insufficient light the plant remains light-green in colour and becomes unnaturally thin and protracted. The buds will also remain smaller with insufficient light.

Saving on light is stealing from yourself!.

The efficiency of the lighting in the grow room can be strongly increased by covering your grow room with reflective materials. You could paint the walls with mat white paint or cover the walls with white plastic. Ensure that the room can be easily cleaned because spraying might pollute the walls quite a bit. Most sorts of your "favourite plants" remain in their vegetative (grow) state when the light cycle is maintained at 18 hours. Your "favourite plant" is a so called short day plant, in this we mean that the plant will start flowering when we shorten the light period. Plants are initiated into the flowering phase by shortening the day period to 12 hours on and 12 hours off per 24 hours. Your "favourite plants" that originate from the tropics do not react to changing day lengths but flower after a certain time. That is logical if you realise that a day in the tropics lasts approximately 12 hours the whole year round. The lamp must hang at a distance from the plants that will not cause any scorching of the leaves. This distance differs with the wattage of the lamp. We recommend a distance of: 400 Watt- 45 cm; 600 Watt- 85 cm; 1000 Watt- 105 cm. Don't hang the lamp any higher above the plants than necessary.

Carbon Dioxide:
Carbon dioxide is absorbed by the plant through its pores. In small spaces, the present carbon dioxide will soon be used up. Therefore the air in the growroom has to be replenished regularly. For this you need to buy an exhaust fan. You have to make sure however that it is powerful enough to replenish all the air at least 20 times per hour. The fan can be connected to a time clock or thermostat and/or hygrometer. To provide for an optimal gas change for the plant we also recommend to place an oscillating fan in the growroom, in order to have a constant air flow along the plants.

In urban areas the carbon dioxide concentration might increase to a higher value than the normal 0.03% which is 300 ppm (parts per million). From regular horticulture we know that adding extra carbon dioxide to a concentration of 0.15% highly stimulates the growth and the speed of photo-synthesis. This results in faster and higher yields. This yield increasing effect is most powerful with intensive lighting and inert substrate cultivation, such as rockwool. Another effect that has been reported by growers is the fact that a higher carbon dioxide concentration makes the plants less sensitive to higher temperatures.

A third effect is that there is less need to ventilate (unless the humidity is too high) because you don t depend on carbon dioxide from the outside air. In greenhouses the exhaust gas of oil-fired central heating is conducted back into the greenhouse. To raise the carbon dioxide concentration in grow rooms, it is usually supplied from bottles. There are two ways to provide for more carbon dioxide in the growroom.

(I) The cheapest way is to buy a pressure regulator that can be adjusted so that after ventilation (when carbon dioxide is dispelled from the room) the right amount of carbon dioxide will be released inside again. The exact quantity you need is something you have to work out yourself. You calculate this as follows: Length x Width x Height of the growroom in metres gives the volume of the room in cubic metres. One cubic metre is 1000 litres. If for instance you want to increase the concentration from 0.03% to the required level of 0.15%, you need to add 0.12% carbon dioxide. Suppose your grow room measures 2 x 2 x 3m , which is 12000 litres. 0.12% of 12000 litres is 14.4 litres. So to this room, 14.4 litres of carbon dioxide should be added to obtain an optimal gas concentration. This needs to be done after every exhaust period. This only needs to be done during the "day period", because the plants only use carbon dioxide when the light is on. One kilo of carbon dioxide is approximately 500 litres. So a 10 kilogram bottle contains approximately 5000 litres. This means that a grow room of 2 x 2 x 3m needs two bottles per grow period.

(II) The second system to keep the concentration of carbon dioxide at the right percentage is by the use of a carbon dioxide meter and a computer controlled pressure regulator. The concentration of gas is constantly measured and the computer makes sure that with a too low concentration, the right quantity of gas is added. The ventilator could also be connected to this computer. This system is not cheap but once it has been installed you don't need to worry about it anymore.

The recommended day temperature with the cultivation of your "favourite plant" lies between 25 and 28 deg C. With higher temperatures the growth will slow down and the yield and quality will decrease (many growers experience this during summer). In the dark, other chemical reactions occur in the plant than in daytime. A lower temperature suits them best. The recommended night temperature lies between 15 and 20 deg C. With temperatures lower than 15 deg C the growth is obstructed, lower than 10 deg C the growth stagnates and lower than 5 deg C will damage the plant. The most ideal situation would be a grow room with both heating and airconditioning.

The roots are especially sensitive to low temperatures. The absorption of nutrients through the roots is an active process. This means that the root needs energy to absorb the nutrients, but also to be able to select these nutrients. The root can, to a certain point, choose which and how much nutrient it absorbs. This process can be seriously disturbed with too low a temperature, because then there is insufficient energy available for this process. Therefore you have to make sure that when watering the plants the water is approximately 23 deg C. With cultivation on rockwool the nutrient solution temperature is held constant with the use of a special twin glass sleeved aquarium heater that has a built-in thermostat.

It speaks for itself that the plant must receive enough water. Don't forget that the water needs of a plant, in time, can strongly differ. Freshly transplanted seedlings and cuttings require less water than a flowering adult plant. It is of great importance that the plant has a well developed and healthy set of roots for the optimal absorption of water (and the nutrients that will be mentioned here after).

Most of the water absorbed by the plant is evaporated via the leaves. By doing so the air in the grow room becomes humid.

Relative Humidity:
The humidity will decrease because of the ventilation in the grow room. To measure the humidity , you need a hygrometer. A high relative humidity is very important for the seedlings in the beginning of the cycle (between 60% and 75%). At the end it is important to keep the RH low (40% to 50%) because it could cause the buds to rot. If the humidity is too high, you need to exhaust more air. If the humidity is too low you could first try to increase it by hanging some wet (clean!) towels or sheets in the room and by often spraying the underside of the leaves (normal tap water). If this is not sufficient you might consider buying a humidifier.

Nutrients in General:
For the healthy development of a plant a number of nutrients are indispensable. The following elements are necessary: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, iron, manganese, copper, zinc, molybdenum, borium and chlorine. Carbon is being absorbed through carbon dioxide. (In carbon dioxide one particle of carbon is attached to two particles of oxygen). Hydrogen and oxygen are mainly absorbed by means of water. (In water two particles of hydrogen are attached to 1 particle of oxygen). These matters have already been explained.
Nitrogen together with phosphorus and potassium are the main ingredients in normal fertilisers.

All proteins, also the ones in the plant, contain nitrogen. All enzymes (these are matters that regulate the character and speed of the chemical reactions in the plant) are proteins. Especially chlorophyl with which the plant produces sugars (with the help of light, water and carbon dioxide) contain many proteins and therefore a lot of nitrogen. From the previous you might understand why nitrogen is such an important nutrient for the plant. When a plant receives too little it is first shown by the colour. Because so much nitrogen is needed to make chlorophyl, a shortage will be noticed here first. The plant will become ailingly light green. This fading starts first with the older leaves. BUT: when there is insufficient light it is of no use for the plant to make chlorophyl which also gives this light green colour. When this is the cause however, the leaves also tend to "reach out for the light" in their shape. With a nitrogen shortage you don't see this. Also with a nitrogen shortage the plant becomes more susceptible to mycosis. With too much nitrogen the opposite will happen. The plant becomes unnaturally dark green and the growth stagnates.
Just like nitrogen, phosphorus is important for protein chemistry of the plant, especially in the regulation processes. A shortage of it is expressed as slow growth and sometimes a purple-ish colouring of the whole leaf. The chance of a phosphorus shortage is small with the right nutrition. An excess is more likely to occur, especially with substrate cultivation, because phosphorus can accumulate in the root environment. When this happens the plant can't absorb enough zinc so the symptoms are similar as with a lack of zinc. (see Zn).
This nutrient is especially important in the humidity regulation. With a potassium deficiency, symptoms of burning occur. (see page 10). With too much potassium there will be a shortage of calcium and magnesium. (see Ca and Mg). During the flower period the plant requires more potassium.
Magnesium is necessary for the production of chlorophyl. With a deficiency the plant will yellow between the veins, initially in the older (strange enough not in the very oldest) leaves. Your "favourite plant" is a true magnesium lover. Too much would make the growth stagnate, but this has never been established with the cultivation.
This nutrient is "built-in" the cell walls and membranes of the plant cells. A shortage might occur in the leaves when the relative humidity is too high (and they cannot evaporate enough water), and with a potassium overdose. With a lack of calcium, the young leaves and new buds die. The plant also becomes very susceptible to mycosis. If the calcium deficiency is being caused by a too high humidity, the entire crop can be ruined in no time through moulding. An overdose of calcium has never been established with this plant.
The plant uses sulphur to build up proteins. Overdoses or deficiency are unknown in practice.
The plant uses iron in its enzymes. When growing on soil, both overdose and deficiencies are unknown. When growing on rockwool however, an iron deficiency might occur as a consequence of a too high pH.

An iron deficiency is easily recognized by the chlorosis of leaf tissue on the growing shoots. Leaves in the shoots have a network of green veins which stand out among the yellow or white tissue between the veins.
The plant also uses this in its enzymes. Deficiencies and overdoses are both unknown when growing on soil. A lack might occur when growing on rockwool because of a too high pH. This is recognized by a yellowing between the veins of the new leaves (but not the very newest).
Copper deficiencies are extremely rare. Be careful not to confuse this deficiency with the symptoms of overfertilisation.
Zinc is also used in the enzymes. A zinc deficiency is usually the result of an overdose of phosphorus. The symptoms are chlorosis of tissue between the veins of top shoots starting at the base of the leaf. A radial or horizontal twisting of the leaf blades in the growing shoots is a dead give away.
The plant needs boron to transport sugars. When there is a deficiency symptoms first appear on the growing shoots which turn brown or grey and die. The shoots may look burnt. A good indication of B deficiency is that after the top shoot dies, actively growing side shoots start to grow but die also.
This nutrient is needed for a few important enzymes in the plant that play a role in the manufacture of nitrogen. Extremely rare, look for another cause.
One of the things you never find in other manuals is the following: We have told you before that the absorption of nutrients is an active process and that plants can, within certain limits, decide what and how much they absorb with their roots. Suppose that a nutrient solution contains nutrient A and nutrient B in equal amounts. The plant grows fine but it happens to use some more of A than of B. After some time the EC has dropped and is adjusted with new nutrients that again contain equal amounts of A and B. But more has been used of A, so after adjusting, the solution contains more of B than of A. If this continues for a while the solution will contain too much of B and too little of A whereas the EC has the right value. With the EC you determine the concentration of nutrients but not WHICH nutrients. Besides, the plant also expels certain toxins through the roots into the drainage water.

For these reasons we strongly advise you not to use the drainage water a second time.