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  • Does LED grow light produce heat?

Does LED grow light produce heat?

Jun 25, 2020 - 6:04 PM

  • Which product should I get for starting up hydroponics in my basement? Do I have to worry about the heat generated? (do I need a fan or anything?)

  • Hello!

    Yes, LED grow lights produce heat. All lamps do. LEDs are generally a bit more efficient than old light technology. This results in fewer watts needed for the same amount of light, and watts equals heat.

    How large is your grow area? Are you growing in a large and open room or in a tent or small enclosed space? Heat (and humidity) can become trapped and build up in small spaces. In that case, it is a good idea to have a small fan that actively ventilates your grows pace and continuously pushes in new fresh air, or pulls out old air, depending on which way you mount it. A cheap hygrometer is a great tool that will help you keep track of both %RH and temperature.
    Here's an example:

    How large area are you intending to illuminate and what type of plants are you planning to grow?

    Share some more details about your grow space and plants, and I'll be able to give better recommendations for you.

  • I'm growing in a basement and plan to hang lights from the ceiling supports, but not sure about reaching power within 6'. I thought I'd start with lighting. I want to start small to see some success, but not so small that it isn't even worth it. Lettuce for sure. Right now in my container garden I have baby spinach and baby rainbow chard and I keep wishing I was all set up to bring it inside because I'm reading that hydroponics gets fast growth, no bugs, no weeding. But I know I need the right light for it to work.

    Oh, and my cilantro came back from last year and bolted almost immediately. I'm thinking I can do much better with that indoors, too. It gets pretty hot and humid here in the summer. We do get frost in the winter, snows maybe a couple of times per year.

    I want to do Kratky but haven't decided on a configuration yet. I saw a DIY system using an under the bed storage container for lettuce, but I'm not sure yet. That would be 8 heads ready to harvest at the same time and there are only 2 of us now.

    Any thoughts on lights or Kratsky in general?

  • Our Z5 LED grow light covers 2x2' area with good intensity for salad in an open room, at a height of 26" above the canopy. If you put up walls around your grow space, a white surface or reflective mylar, you will get a slightly larger area with good intensity as this will contain stray photons and concentrate them where we want them (on our plants). Light intensity will also be more even, as this effect is greatest in the outer edges and corners.

    Kratky is a great way to start and you can always add a small air pump and air stone to the reservoir (making it DWC) whenever you want to step up your hydroponics game one level. Roots love oxygen and it will help with plant growth and root health. It will also help prevent accidents in the reservoir, such as unwanted bacterias. Basically, bad bacteria thrive in low-oxygen environments while good bacteria thrive in the opposite. Also, make sure that your reservoir is light-proof, as light will have a negative effect on the roots and also promote growth of bad bacteria and algae.

    Heat produced by the lamp will not be a problem if you have a whole room as grow space. Your ambient room temperature could be a problem in itself, but a grow space of this size shouldn't be affected noticeably by the lamp.

    Eight heads of salad is a fair amount to harvest in one go but you can also plant one seed every week and harvest one head weekly. With eight heads, that results in a 56-day grow cycle. Different varieties require different amount of days to mature. You could look into this and pick a variety that fits well with your quantity of plants.

    I hope the above was helpful. Please let me know if you have any other questions and I'll be happy to answer them.

  • From what I read about Kratky, it seems like you need to plant all at once to keep the rate of absorption and evaporation in line with root growth. In other words, won’t the later plantings have difficulty if in the same reservoir?

  • Yes and no. Yes, root length of the youngest plants will have to match the distance down to the water level. If no refill or change of nutrient solution has been made, the water level might be too low for the new plants to reach it.

    One detail that makes the Kratky method so popular is that there is almost no need for maintenance if you don't want to. However, it won't hurt to re-fill or even change the nutrient mix once in a while. Both to get the water level a bit higher, as well as to add new nutrients and keep the strength of your solution balanced for all plants during all stages. Some growers do it every week, some do it every other week, and some growers never touch it at all.
    You might want to consider this option if you don't want to harvest eight heads at once.

    Tools to measure PH and EC will also make everything easier and prevent accidents.

  • I have a liquid pH test kit for my fish tank.
    EC only measures the salts, right? how do you test the other part of the fertilizers, I've wondered. And how necessary is it? Also, I was planning to use my tap water after running it through the filter I use in the kitchen, since I don't have a RO system in my house.

  • It is great that you can test PH, and you don't necessarily need RO water to succeed. It depends on how much minerals you have in your tap water. Measuring the EC of your tap water will tell you if it's good or not and if you need to clean it or not. Oftentimes well-water will have a lot more minerals than communal water. Measuring the EC will also make troubleshooting a lot easier. You'll be able to see if your plants use a lot of water, a lot of nutrients, or equal parts of both.
    This also makes it easier to know how strong nutrient solution you should re-fill with and/if you should lower or raise the concentration in general.

    More often than not, hydroponic nutrients are salt-based (non-organic)
    It is possible to grow hydroponically with organic nutrients but it makes it more difficult and more prone to accidents in the reservoir. If you want to keep it simple, you should start with salt-based nutrients and then change to organic nutrients in the future.

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