lights and fertilizer

Discussion in 'Cannabis Grow Rooms and Greenhouses' started by sillypuddy, Apr 29, 2007.

  1. sillypuddy

    sillypuddy Member

    I've got two spindly 4 foot sativas growing indoors in 5 gallon pots each. The growth medium is pro mix, 80 % peat mos with vermiculite, perlite, and limestone. Because it's not soil, is this hydroponic? So, how often should I water and fertilize them?
    Also, I'm using six blue incandescent 'grow' type bulbs, three overhead, and three from the sides. Changing the light system is unfortunately NOT an option. Disregarding electricity costs, has anyone achieved moderate success with this type of lighting. I'm not looking for Amsterdam quality.
  2. T.H. Cammo

    T.H. Cammo Member

    By sillypuddy:

    "Changing the light system is unfortunately NOT an option." - Well, it looks like you are out of options. Without enough proper light, photosynthesis ain't going to happen! After "spindly" comes "fell over". Adding nutes without enough light to metabalize them will probably toxify the environment.

    "Because it's not soil, is this hydroponic?" - No, it's called a "soilless mix".

    "I'm not looking for Amsterdam quality." - You're well on the way to not finding it!

    Sorry if I sound very negative, but you will get a lot better results if you find out about something before you actually try it.
  3. sillypuddy

    sillypuddy Member

    actually, the plants look pretty healthy, and have grown quickly. How often should a soil-less mix be watered and/or given nutrients?

  4. T.H. Cammo

    T.H. Cammo Member

    As for watering - 5 gallon buckets are perfect for the "Heft" method. Start by slowly adding a little water and allowing it to soak in. After a few minutes do this again, this allows the water to distribute evenly into the soilless mix. Keep repeating this untill you get a little runoff out of the drain holes. At this point, lift the buckets to feel how "heavy" they are - 5 gallon buckets should be pretty heavy unless you have a "dry pocket" in the mix. Get used to feeling the weight of the buckets every day. It gives you a good chance to get up close and personal with your plants and it also lets you know when they need watering. Don't over water - that is harmful not helpful. When the buckets feel very light it is time to water again, as above. If the leaves begin to wilt a little, that means that you have waited to long. The trick is to let them dryout some, but don't make them wilt. You'll get the hang of it!
    As for nutrients - it depends on what you're using. Many growers never use more than half the label recommended strength. How often and how much to use is a solution only arrived at by comparing the label instructions with your growing conditions. But I would advise to break down the doses so they are smaller and more frequent (1/2 oz. every week instead of 2 oz. every month - for example). Remember that overwatering and overfertilizing are the two biggest problems with beginners. Start weak, about 1/4 strength - each time you apply nutrients you can make the mix a little stronger. If the leaves show a little nute burn, then drop the strength back a notch. If the leaves show a severe nute burn, flush the buckets A.S.A.P.
  5. sillypuddy

    sillypuddy Member

    ok, thanks for the tips.
  6. sillypuddy

    sillypuddy Member

    hey, can anyone tell me if plants get burned from the actual heat of the lamps, or just from too much light?
  7. T.H. Cammo

    T.H. Cammo Member

    The short answer is - "Both of them".

    There are two things happening here, "ambient heat" and "radiant heat".

    Ambient heat is caused by the hot lamp acting as a heater and warming up the whole grow space through "convection" - this is what burns the plants, if the ambient temperature is too high.

    Radiant heat is caused by the impact of the photons of light being "radiated" from the lamp. Radiant heat passes through air regardless of the "air tempature" - this is why the sun can "feel" warm on your skin, even on a cool day. The radiant heat from the lamp is controlled by adjusting the distance between the lamp and plant. This is what is called "light burn", if the radiant temperature is too high.

    While the ideal ambient temperature for growing is about 73-75f. (opinions may vary!), the radiant temperature (at the canapy) can do very well at about 90f. The radiant temperature can be tricky to measure accurately with a thermometer - just use your hand. Hold your hand, opened flat, just touching the canapy; hold it there a while till the temperature stabilizes. The radiant temperature on your hand should just feel warm - not hot, then you know your lights are at the right distance.

    This is why air cooled reflectors and "cool tubes" can be used closer to the plants, boosting efficiency, because the ambient heat keeps getting sucked away (that reminds me of a girl I knew in High School - but that's another story!!!).
  8. sillypuddy

    sillypuddy Member


    I actually changed my blue incandescent bulbs to compact flourecsents. Two 27 watt ones at 2700 K, and one 27 watt at 6100 K. These ones seem much cooler than the other ones.
  9. sillypuddy

    sillypuddy Member

    Well, I've got 20,000 initial lumens from a series of 6500K CFL's for two 3-month-old female sativas. I know this is less than a powerful HID, but those things have to be a couple of feet away from the plants, whereas these are within 3 inches. If anyone wants, I can give progress updates.
    By the way, can anyone tell me if I need to fertilize Pro-Mix soilless medium more often than I would fertilize soil? If so, how much more?
  10. bush basher

    bush basher Member

    hey silly, i'm using cfl's at the min. 4 of, there 1200 lumens each and i'm only growing 1 plant so far. it's in its 3rd week. when i build my grow room i'll be using them 4 cfl's (moveable) on top of each plant (obviously 4 of them) i'll also have 2 4 foot flourescent tubes on the lid, which are 58w each and i'll have 2 more on the sides of the room keep me posted to see how yours are going. my pics are posted in the growing section!
  11. sillypuddy

    sillypuddy Member

    have you ever successfully flowered with fluorescents?
  12. bush basher

    bush basher Member

    no, this is my first grow. however thats all people used to use and there has been many great yields off them so we'll see.
  13. T.H. Cammo

    T.H. Cammo Member

    Many "great" yields from flourescents?
  14. posedat

    posedat Member

    pesimist... lol... o think that with the amount of flo's BushB is using.. he might get a reasonable yeld off of his first grow.. you know how it is for the first timers.. everyone is just happy if they get more than 20 grams offa their plant.. i bet my collection of useless junk from around the house you tried everything to speed up your first grow just to get the that first puff of your DIY weed
  15. sillypuddy

    sillypuddy Member

    from what I understand, it's all about lumens and spectrum. If you only have 1 or 2 plants, than maybe....
  16. bush basher

    bush basher Member

    Many "great" yields from flourescents?

    yes you heard. sorry i'm just a newbie but i've read every forum cover to cover and i know hell of a lot now. (prob not as much as you experienced growers) but in one of them some 1 has experimented with bulbs. flouro vs cfl's vs hps

    check it out, really informative. and if you had the same wattage of cfl's as you have hps which would come up tops then??? you read an then decide. let me know what you think!!!

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