Leafs yellowing

Discussion in 'Growing Marijuana Indoors' started by bigtree, May 27, 2006.

  1. High,
    I have an indoor grow one plant with two clf lights and a fan blowing its all on 24 hrs a day. The bottom leafs not the circle leafs but the true leafs are turning yellowhish, light green.
    Thanks,
     
  2. I've got the same issue, How far away are your plants from the light, and how many lumins per square foot - It seems I have the same setup.
     
  3. the lights are about 2 inches from the plant, all i know is that each bulb is
    42 Watts.
     
  4. Then likely its anywheres from 1000-1600 lumins. Make sure your plants are 3 inches away. Also do you have an type of relfector? Mylar(if thats spelt right) or foil? (also never use mirrors since they absorb light)...

    Also, tell me your watering schedual - How much and when.
     
  5. No i don't have any reflectors, I put my fingers in the dirt a couple of inches deep to see if the dirt is moist. I'm not sure how much to water, I've heard that white surfaces work good as reflectors.
     
  6. Depends on the material of the reflector. White paint of a closet gives about 33% reflection. Foil gives about 75% and Mylar gives about 90 %. Reflectors are especially important for inner and side leaves. I suggest you go down to the hydroponics shop for some mylar or tape some foil to the sides floor door and even ceiling of your grow space. Its easy and increases efficiency I promise!. The more like the better.

    Yes water enough to keep the soil 2 inches down moist. Over watering attracts gnats and messes with nutes(some nutes).

    I relealized my issue was from light distance.....using cfl's I had them atleast 7 inches away .....=o.......Im stupid, this is my first time. I have a post about yellowing leaves, I'm about to post pictures of my 19 day old plants. Take a look if you want and compare so we can help eachother better. I need a grow buddy anyways ;)
     
  7. High folks.
    I just wanted to interject a few things here. First off white paint has more like a 90% albedo and Mylar around 80%. Do not use foil, it is no good.

    CFL's really should not be any further than three inches from the closest plant tops. The further and further you go the more drastically the lumens drop off.

    Bigtree, what type of soil are you using? How old are your plants? And what type, how often and how much fertilizer do you give them?
     
  8. White paint on - a sheetrock wall - absorbs some light if I am not mistaken. Foil is good to use when mylar isnt available because its reflects lumins from being absorbed by watever color or material behind it.

    But im just going off my grow book from hightimes.
     
  9. Aluminum foil reflects too much heat relative to its light reflectivity (that's why it's sold for cooking, duh). It can cause hot spots that burn plants.
     
  10. Very true! But foil has its advantages ;). My old roomate used foil in his flowering room and mylar in his vegitating room. Since foil creates more heat and generally less humidity, the buds on his flower cycle plants got frostier than all hell. Christmas in july I'd say ;)
     
  11. I think my problem was pre-fertilized soil, should I transplant to better soil?
     
  12. could be, but not all pre ferts are bad, can you tell me the specs of the soil?
     
  13. It is miracle grow, I think it says it feeds your plant for a month or something like that.
     
  14. that soil should be fine - you likely just watered it too much the first time. Dont water it for about 5 days, MJ likes off and on dry periods. In the mean time make sure you find a spray bottle, like the windex bottle and clean it thoroughly. You can mist your plants and spray the soil in your container more thoroughly with it. Use about 1/4th of the bottle (if windex normal size) for each plant on watering days. I do mine every 5 days, but the strain I have seems to adapt well to that sycle.
     
  15. The top leafs also have the tips yellow should I worry?
     
  16. No Chill on the watering, give them as much light and Carbon Dioxide as you can. If yellowing persists it means you need nitrogen or your PH is off. In that case you need Lime, or you can add a little saw dust to your soil.
     
  17. Bigtree,
    Do not use Miricle Grow soil with time release ferts. It is terrible for seedlings and always over-ferts them. Over or under watering does NOT cause yellowing leaves. Your soil is burning them. If you insist on using the least of the reflective surfaces, tin foil, at least use the dull side OUT. Here is a link on what MG soil with time release does to plants. I suggest Salviasagewise and bigtree that you guys read the entire thread and follow my links to other pictures. http://forum.grasscity.com/showthread.php?t=84490&highlight=PGAMG
    Bigtree, if you want your plants to flourish get them out of that soil.
     

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