Help needed

[ifsixwasnin9]

I have 2 plants in 7th week: white widow hybrid and California gold (don't know which is which). The larger plant (one on left) developed yellow leaves at the bottom about 4-5 days ago and now it's showing brown spots and a little yellowing on the 2nd row. The top of the plant is green and still growing. The other plant is doing pretty good although it has a couple yellow leaves at the bottom, too.

1. Used commercial potting soil mixed with a little vermiculite and bottom 1.5" is all vermiculite.
2. Transplanted in 4th week from 2L bottles to larger pots and took them a week to recover and start growing again.
3. Grow area is 3Wx2Dx5H.
4. 250W HPS light and added 100W HPS light 3 days ago.
5. Light time until last week was 12-13 hrs, now it's 14-15 hrs.
6. I kept the plants a good 2-2.5' from lights and moved them to about 14-16" three days ago.
7. Using 20-20-20 diluted (~40-50%) nutrients 2x/week. I added magnesium (1 teaspn/gallon) 3 days ago.
9. I was watering (distilled) every day just to keep the soil moist, not overwatering.
10. I have an external and internal fan and temp is 75-80 degrees.
11. I don't know the ph because my crappy meter doesn't work. (I ordered a new tester and should be here 5-7 days.)

The plant in question curls its leaf edges while under light. Out of the light the leaves straighten out and looks great in the morning.
Only thing I can think of is a bad ph or low CO2 levels. I know these plants are a little stunted but this is my first grow and it's harder than I thought. Anyone?

(Large photo just a tad overexposed. No sign of yellowing in top half of either plant.)

 

[powerplanter]

I think thats fairly normal. Your plants look fine to me. I think they start to turn brown because the light isn't getting to the lower leaves as much as when they were smaller.

 

[leafminer]

Looks a bit nitrogen deficient - on pic 3 you can see yellow mottling beginning on leaves higher up, if you look carefully. What's in the "soil"?

 

[ifsixwasnin9]

I used Scotts potting soil and I mixed maybe 8% vermiculite with it. Maybe I should flush and start using full strength nutrients 1x/week? Both plants were totally green 2 weeks ago. Adding the 100W HPS 4 days ago made the grow area brighter which I think it needed. The brown spots just started maybe 3-4 days ago on the one plant. I actually started them out more than 2.5' away from light and now they are at least 20" away.

 

[legalize_freedom]

your lights could be closer...I'm surprised you don't have more stretch from keeping them so far from the light. put them as close to the tops as you can without burning. Test this by holding your hand at the tops of your plants for 1 min...if your hand does not get too hot then the plants will not. You should be able to get those lower wattage lights at least 12-10 inches from the tops.

If you have no way of checking your pH it could be that the (N) is locked out from pH being out. They look okay, I'd wait until you get your meter and then you will know more. To just go adding more (N) without knowing the pH will be pointless right now, if it is locked out. When you get your meter, run some pH'd water through it, and check your run-off, make adjustments after knowing where your soil is.

 

[pcduck]

I would also be concerned about the vermiculite you added. Most growers use perlite as an amendment to improver aeration where as vermiculite retention of water and the pH of vermiculite is essentially neutral (7.0-9.5) but owing to the presence of associated carbonate compounds, reactions are normally in the alkaline direction.

 

[Alistair]

ifsix, why did you have the lights on for 12-13 hours? For vegging, 18/6 or 24/0 is best. Your plants look good to me, and as the others said, it looks like a possible nitrogen deficiency, but wait for your meter to arrive before deciding.

 

[Old_SSSC_Guy]

They look fine, maybe a bit pH locked. Watch increasing the light cycle it will confuse the plants. Consider watering with bubbled tap water instead of distilled, and feed a tiny amount of nute at each watering instead of weekly.

Vericulite is made to retain water - it is better to drain than retain...

 

[ifsixwasnin9]

Update: The plant now looks in worse shape since 24 hrs ago. The lower half has a lot more browning and looks like the leaves are dying. I removed the plant from the pot to add some stones at the bottom so I can get some runoff (I don't get any runoff) and the vermiculite at the bottom is compacted very tightly to no more than 3/16" and the bottom is engulfed in roots. I have 1.5-2.25 gallons of soil and I would say I have much less than 5% vermiculite overall. Do you mean the nitrogen is "locked out" due to absorption by vermiculite? There has to be some available nitrogen for the plant. I was lighting for 12-13 hrs because that's what my schedule allowed and the room isn't heated so it's hard to leave them in during my sleep.

 

[ifsixwasnin9]

More detailed photo.

 

[cuy103]

If you have no way of checking your pH it could be that the (N) is locked out from pH being out. They look okay, I'd wait until you get your meter and then you will know more. To just go adding more (N) without knowing the pH will be pointless right now, if it is locked out. When you get your meter, run some pH'd water through it, and check your run-off, make adjustments after knowing where your soil is.

:yeahthat: I completely agree. Don't do anything until you get your pH meter!

9. I was watering (distilled) every day just to keep the soil moist, not overwatering.
11. I don't know the ph because my crappy meter doesn't work. (I ordered a new tester and should be here 5-7 days.)

That means the soil has been soaking up and sitting in the "unknown pH water" for 7 weeks. You could have been using water with a pH of 5.8 or 7.2 or other variations that would make the soil acidic or base; like you said, "you don't know the pH..." I was doing the same thing and found out the hard way that most of my problems were caused by this. Now, everytime I water I check the pH and adjust.

I suggest watering until most of the soil is dry or damp. I would avoid keeping the soil moist because too must moisture/water will "drown" the roots. Letting the soil become dry will allow the much needed oxygen into the root system. I find the best method is to pick up the container after you give the plants their watering. Now you have an idea of how heavy the container is after watering. Wait a couple of days, 3-5, and check again how heavy is the container. Eventually, you get a feeling of when to water your plants.

My 2 cents
- Check the pH of the water before giving it to your plants!
- Only water until most of the soil is dry or damp

Hope that helps. BTW, don't do anything until you get your pH meter!

 

[ifsixwasnin9]

Who would use tap water? It contains trace amounts of minerals and chemicals such as zinc, iron, copper, fluoride, etc. not to mention microbes. Distilled water doesn't contain any of that.

 

[The Hemp Goddess]

While I do not believe that the light schedule has anything to do with this problem (I believe you have pH issues), you are going to have to do something about your light cycles. It is really bad to be changing the light cycle like that--you are almost asking for hermies. You really should be giving your girls at least 18 hours of light a day for good vegetative growth. And they are going to need 12 hours of uninterrupted dark to flower--the same time every day.

 

[legalize_freedom]

Who would use tap water? It contains trace amounts of minerals and chemicals such as zinc, iron, copper, fluoride, etc. not to mention microbes. Distilled water doesn't contain any of that.

Although you are correct that tap does contain all of these elements, you have no way of being able to tell the amounts of each, or what is exactly in there. I would much rather use RO or Distilled and add the exact amounts of trace minerals, and nutrients that I'm capable of doing with fertilizers. Microbes are only going to play a small part in the symphony if you are using chemical ferts, but are also avaliable at your local hydro store.