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Any tips on growing marijuana with your LED light?

Nov 6, 2020 - 7:56 AM

  • Hi,

    I purchased your 1000W LED growlight recently. I was wondering if you could aid me in the process of growing marijuana. From a small plant that’s only a few weeks old until harvest. Maybe light cycle and distance from canopy.


  • Hello,

    Thank you for reaching out.
    We're happy to have you as one of our customers. Has the Z5 met your expectations this far?

    Absolutely. We are happy to assist wherever we can.
    Is your plant(s) photosensitive or auto-flowering type?
    What size is your grow space and how does your plant look like today?

    For both photosensitive and auto-flowering plants, 18 hours will work well during the vegetative phase, together with a light intensity of between 150-500 PPFD (µmol/m2/s). 150 PPFD when it has just germinated, and upwards 500 PPFD in the late vegetative stage just before it starts to flower. When it's flowering, It will be benefitting to be above 600 PPFD (12-16" between lamp and top of your plant)

    Always try to increase light intensity in increments over several days. It is always better to give too little, rather than too much.


  • Thanks for replying. I am currently building the area right now. What would you recommend for 2-4 plants? 3 feet x 3 feet? (2 plants to start)
    I will be using reflective materials for the walls.
    I have the auto flowering variety.

  • Hi,

    We've made a video about tent sizes that is very informative:

    It is expensive to produce light, both in terms of hardware required to make a lamp, and in terms of electricity needed when operating a lamp. Minimizing the space to maximizing the light intensity is wise.
    How large space you need will depend on the strains you are growing, as well as your grow style. There are techniques, such as Topping, Manifolding, Low-Stress Training, and Screen Of Green, that will make your plants spread out wider and make them take up more space than if you don't train or tie them at all. one plant can be anywhere from ten inches wide to four feet.

    It all depends on the strain and growing technique.
    Since you are growing auto-flowering plants, you most likely won't be topping them or applying other techniques that are causing a lot of stress. Plan for this growth, but also for upcoming grows. Are you intending to mainly grow auto-flowering varieties even in the upcoming grows?

    Also, since you are building the grow space yourself, how easy will it be to change your mind down the road and increase or decrease the size of it? Starting out small might be wise if it is easy to change the size of it down the road.

  • Thanks. I can change the space pretty easily. I was thinking of making 4, 4 foot sections, then piecing them together in 3 foot sections so i can expand easier next time. But for autoflowering variety, do I just plant and grow? do they not require any techniques to enhance the sizes/lateral area? I have a few regular feminized varieties, but i figured I would start with the easier variety first.

    What would the distances from the plant would you recommend the light being in the veg state? Sorry, I don't have a photometer... So a rough estimate would be ok.

    Do autoflowing plants require a higher PPFD when getting to the flowering state? Also, do you recommend changing the light setting from veg to flower?


  • Yes, autoflowers are just plant-n-grow. They don't handle stress well and are usually sowed in a large final pot right away to minimize this.

    Different strains have slightly different preferred maximum intensity.
    Apart from that, there is no major difference that divides AutoFlowering (AF) from PhotoSensitive (PS) species during the vegetative phase. The big difference occurs when the flowering phase starts. As you may know already, flowering happens automatically by AF species after a set number of days, no matter the length of the photoperiod.
    By PS varieties, flowering is induced by changing the photoperiod from long days of 18h (18 on / 6 off) to short days of 12h (12 on / 12 off).

    For both AF and PS, a photoperiod of 18h is great during vegetative phase. When transitioning to flowering, the 18h photoperiod can be kept as it is for AF species, as a long day won't inhibit AF plants from transitioning to flowering.

    We have made detailed maps that show what intensity is created by our Z5, on multiple heights. We have also included recommended light intensities on this map. These maps can be found on our website, but I'm attaching it to this mail as well.

    Our lamp is designed to put out a balanced spectrum with both buttons activated at the same time, which can be used from seed to harvest. As some growers still want to use an extra blue spectrum in the first week(s), we've divided the diodes into two sections, blue-dominant and red-dominant. The blue button emits 38% of all light when both buttons are used. Looking at our intensity maps, we can multiply any value with 0.38 to see the intensity produced by the blue button alone. Personally, I always have both buttons activated.

    Here's a short write up on how to achieve a certain intensity and what distances you should account for:
    Appropriate light intensity depends on many different factors, such as strain, temperature, and humidity (to name a few), but generally, we recommend 150 PPFD until the second set of leaves are showing. Progress towards 200 PPFD when the second set of leaves have unfolded. When your plant is 4"/10cm tall and/or has three sets of leaves, it should handle 250 PPFD quite well. When it is has become a young adult and is in its vegetative phase, slowly work your way to 400 PPFD, or slightly higher. When switching to flowering, an intensity of 600+ is recommended. When light intensity passes 500-600, photosynthesis will slowly become light-saturated and instead become limited by the availability of CO2. We recommend to not grow in intensities higher than 900-1000 PPFD, as this is where photosynthesis more or less becomes light-saturated, but it could be done in the mid to late stage of flowering if you are on point with watering, temperature, nutrition, airflow, humidity, etc.

    150 PPFD is achieved at 36/90cm
    250 PPFD is achieved at 30
    400 PPFD is achieved at 22/55cm
    600 PPFD is achieved at 18
    900 PPFD is achieved at 12"/30cm

    If you want to give your plants 150 PPFD during seedling-stage with both buttons, hang the lamp at 36/90cm.
    If you want to give your plants 150 PPFD during seedling-stage with only blue button, hang the lamp at 22
    /55cm. (400*0.38 = 152)

    The numbers above are based on the center spot intensity below the lamp. The intensity will decrease the further the plant(s) is placed from the center spot, so keep that in mind.

    As always, let me know if anything was confusing and if you have any other questions. We know light can be tricky in the beginning.

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