Light is vital for every plant, including cannabis. Cannabis plants need light, just like humans need air, because it is in the light that photosynthesis takes place in the leaves and stems. This is what allows the plant to grow and develop.
That’s why the right light – this is the first thing to take care when growing plants! Lack of light, either indoors or outdoors, can lead to stunted growth.
Lack of cannabis light also leads directly to a reduced yield. The fact is that in order to grow up the plants need energy which is already in short supply due to a lack of photosynthesis. And yet this same energy could be spent by the plants to thicken the stem and buds, increasing the quantity and quality of the crop.
External signs of a lack of light
Excessively elongated cuttings. Hemp leaf cuttings become thin and disproportionately elongated. They curve, trying to turn the leaves toward the light source.
Thinning of leaves, shoots, and trunk. Cannabis leaves become faded and lifeless, and the trunk and branches become thin and flaccid. As you approach the harvests such bushes will need to be tied up, because otherwise under the weight of the inflating buds the stem may not be able to withstand.
Stretching out in height on the background of the general weakness of the bush. Feeling the lack of light, the plants begin to stretch out in height, but they become weak.
Yellow color. If the leaves receive insufficient light for a long time, they will turn yellow, and then die off altogether. Often the leaves on the lower levels of the bush turn yellow and die off, while the top has no such problems.
How to deal with the symptoms of a lack of light indoors
Whatever bulbs are used in the grow box, you should always watch carefully for signs of a lack of light in order to take action in time. These measures at first glance are simple – give the plants what they lack. Namely light. How to do this, you have to decide according to specific conditions and opportunities.
If the lamps are positioned too high from the tips of the bushes, you need to lower them so the plants get more energy.
You can change to a higher wattage bulb.
If only LED lamps have been used, it is best to add more DNAT lamps to create a combined light.
If it is not possible to lower the lamps, you can raise the pots with the plants to the right height.
If the height of the room does not allow you to give the bushes a lot of vertical light, you can additionally use side lights. This will help to provide light to the side shoots as well.
If you cannot provide the plants with even lighting on all sides, one great way to solve the problem of a lack of light is to rotate the pot 90 -180 degrees about once every two days.
By giving the bushes more light, the grower can expect the stem and cuttings to gradually thicken. The seedlings will fill with life and give a good harvest at the beginning of the harvests.
How to determine the distance from the top to the lamp to avoid the symptoms of lack of light? Let’s look at several ways.
The well-known “grandfather’s” method
Previously, growers used the “back palm” method, which was suitable in the case of lamps DNAT, DRI or ESL.
You have to turn the lamp on and wait for it to warm up.
Extend the palm of your hand with the back of the hand toward the light, placing it at the distance where the cannabis tops start.
Hold the palm for 15 seconds.
If you feel the skin burning, the lamp is too low. In this case, you need to raise the lamp a little and do this experiment again.
Today the method is rarely used, giving way to more modern and technologically advanced ways of organizing lighting.
The rule of inverse squares
In order not to make mistakes in the organization of lighting in the indoors, you need to remember the basic rule. It is based on the optical law of inverse squares, which shows the relationship between the distance from the fixture and the level of illumination.
Here are some examples to demonstrate this relationship:
Twice the distance, four times the illuminance;
Twice the distance – 4 times the illuminance;
3 times the distance – 9 times the illuminance, and so on.
Luxmeter – easy and quick to determine the distance
Grovers who decide to purchase a light level meter will be able to determine the distance with great accuracy.
In the case of LED lights it would be difficult to measure the light in this way, but with the other types of lights the height can be adjusted perfectly so that the plants are not in danger of lack of light!
How to combat the symptoms of a lack of light in the outdoors
Lack of light when preparing cannabis seedlings for planting in the outdoors is one of the grower’s unfortunate mistakes. During the germination stage, the seedlings need especially plenty of light. Additional sources should be used when growing in a grow box. If seedlings are growing on a balcony, be sure to choose a sunny side. Transplanting seedlings to the open ground, you should also choose a non-shaded place, where the bushes will be spared the problem of insufficient light.
What bulbs to use in indora?
The best lighting for hemp is sunlight. This is why indor growers are always faced with the important task of creating conditions that are as close to natural as possible. To avoid the problem of inadequate light in indoors, you have to choose the right lamps and place them at the right distance from the tops of the bushes.
The question of what is the best lamp to use when growing indoors has no clear answer. Every advanced grower has his own “recipe” for the ideal lighting system arrangement. But there are some general rules.
Gas discharge lamps are considered an indispensable source of light in indor grovelling. The wattage of these lamps will depend on:
the size of the room;
Number of plants per 1 m²;
Advantages of DNAT, DRI:
can be used in a large area;
great scalability – that is, the ability to adjust the light level;
high light output, the ability to penetrate deep into the foliage and not just illuminate the top.
Disadvantages of DNAT, DRI:
Takes time to warm up.
Cannot be purchased at a regular hardware store.
To use this type of bulb you need a grow box to be at least 1.5 meters high. The lamps should not be placed too low – this can cause the other extreme – light burning. The optimal distance from the lamp to the head is 30-60 cm (depending on wattage).
Be sure to take care of ventilation, because these lamps emit a lot of heat, the excess of which must be removed.
Experienced growers advise to use DRI lamps for hemp at the vega stage, when the shift of the color spectrum to the cold range with bluish shades is especially important for the bushes. DNAT lamps are best used when plants are transitioning to color. They are dominated by a warm spectrum of light with orange hues that are as close to the natural light spectrum of the sun as possible.
Many professionals advise using both DRI and DNAT at the same time to give bushes more energy and provide plants with the full light spectrum. By combining DRI and DNAT, growers achieve the full yield potential of each variety.
Energy Saving Lamps (ESL)
Energy-saving lamps are a great option for growers who aren’t looking for huge yields. They are not recommended for use on flower, because these lamps do not give the plants the right amount of energy. But for the initial stage of growth of clones they are perfect. Soft light will be enough to avoid its deficit. And at the same time the light is not damaging to the still growing seedlings.
Pros of ESL:
Suitable for small grow boxes with a shortage of height – a few medium-power ESLs can be placed just a few centimeters from the crown.
Can be purchased in the regular hardware department of the supermarket.
Don’t use much energy.
No special ventilation system is needed because ESLs do not generate heat.
A good beginner’s experience that doesn’t require a lot of investment.
Cons of ESLs:
Not suitable for large plantations.
Not suitable for tall plants.
To achieve efficient lighting, it is best to choose a few ESL bulbs of lower wattage, because high-powered bulbs can heat up just as badly as DNAT bulbs.
LED bulbs (LEDs).
Not a bad option for hobbyists, which has both advantages and disadvantages. Advantages are cost-effectiveness and the absence of the heating effect. Among the disadvantages are the monochromatic spectrum and insufficient power. Of course, the developers of lamps are constantly improving them – and the LEDs of the new generation have partially overcome the shortcomings of their predecessors. Diodes at 5 watts allow you to give plants more light, and therefore – more energy. In one LED lamp can be several diodes with different wavelengths of light. But as a rule, these models also consume a lot of electricity, and they are not cheap.
Ideally, it is better to use LED lights as an additional source of light. You can combine it with the same DNAT.
HID systems – the optimal solution
The optimum solution, proven over the years, are HID systems, i.e. lighting systems that use both DNAT and DRI lamps. This combination is also suitable for huge plantations and for a few plants. HID systems are usually already sold with everything you need, which is very convenient for growers.
Components of HID systems include:
Ballast – a device that will make the connection to the power grid safe.
Luminaire – located around the lamp, reflecting the light and redirecting it to the plants. The function of the lamp is to amplify the brightness of the lamp and obtain uniform directional light. By design, fixtures can be divided into winged fixtures, cooltubes, and air-cooled fixtures.
Fan + air-cooled – a system that prevents the bushes from overheating.
Timer – adjusts the duration of the artificial light day by turning the lighting system on and off at the right time.
Coal filtration (if necessary to get rid of odors in the growroom).
Proper lighting is the key to a good harvest, because not only the growth rate, but also the thickness and density of the buds depends on the light. Giving enough light to the bushes, growers will be able to succeed in growing cannabis and get the results that the grower announces.