Problems downunder

[ralph]

Hi guys, Im a first time grower from down under (australia).
I have three plants, soil, still in veg (11 inch, 5weeks old). They are growing in my indoor grow box, ventilated by two exhaust fans (one low down and one high up) 400w Hps light, about 15 inches away. (View pic). 2 gallon pots. Temp is max 84, min 72. Humidity is unknown, but the grobox is in a dry room, so i have placed some open water in the grow box. I gave them some ferts last week (thrive all purpose food - 27-6-9) half dose of reccommendation). I have also used superthrive (hormone) a few times. I have a soil ph meter (the type you put into the soil) It reads 7. I water every 2nd day or when it needs it.
The plant is growing well, but by the pics you will see the problems. I have spent a lot of time reading and havnt been found a soultion.

Also, the last pic is what i found mating on the plant when i was taking the pics.


Please help
ralph

 

[sgtsmoke]

did you get the problem after adding your superthrive and the thrive all purpose food?

i am no pro but i think you over did it with the nutes. 27-6-9)
usually you go with 20-20-20 potting soil

thr flushing the plant and see what happens.
the bugs that i see i have no idea.i am still a newbie so i have no clue

the brothers grunt and hick will prob give you better answers.
kade nows alot to

 

[ralph]

thanks for the reply. about 2 weeks ago, the bottom leaves were turning yellow, dying and then falling off. I think it was eithier a N or Mg problem. So i added the thrive fertiliser and some epsom salts. The plant recovered well and started to grow quickly. These spots appeared soon after, and have been around now for about a week now.

 

[Hick]

The "new" growth appears relatively healthy. You won't be able to repair the damage that is already present.
#1...identify and eliminate those bugs..Identify your pests...or..Pest identification
#2..give that bottle of "Super thrive" to your worst enemy. Others will differ in opinion, but "I" have had nothing but negetive results with it.

 

[ralph]

thanks hick. What to you think is causing these brown spots, drying of middle leave? Superthrive? bugs? Over fertelised? should i flush?

 

[Hick]

...I believe those are fungus gnats. They feed on the micro hair roots in the soil, as a larva. The very roots that are used to feed the plant. Certainly "part" of the problem, IMHO. Gnats are usually presnt when the soil is kept "too moist".
If the yellowing was diminished when you added fetrts, I "doubt" the problem is over nutrients. The soil PH seems.."okay"..not perfect but shouldn't be out so far as to cause lockout.
Have you/do you check the ph of your nutrient mix?..water?..
How long have the plants been in the 2 gal pots?..What soil mix?...Water source?..
As long as the new growth is healthy, "I" wouldn't flush.

 

[ralph]

Thanks hick.

So you think that this is the problem? fungus gnats are causing these brown spots and yellowing? How do i fix this problem? Could it be anything else. i tried to find pics online with a similair problem, but failed.

Bit more info;
Oragnic soil (neautral, the lady said it was the best for a herb garden. hummos, great drainage etc)
2 gallon pots since week 2. (now its in week 6)
I use filtered tap water. I also let it sit in the grow box for 24 - 48 hrs before watering.
I measure the ph with a soil ph meter, which i stick into the soil after watering.

thanks
ralph

 

[Hick]

They could be Fungus gnats or Shoreflies....same treatments..
http://www.hort.uconn.edu/IPM/greenhs/htms/fngnatser.htm
http://www.doityourself.com/stry/fungusgnats

there are a few pesticide "drenches" that will kill the larvae and eliminate the problem.
An economical, simple, organic method,...keep a 1-2 inch layer of "dry" sand on top of your medium for a few weeks. Allow the pots to dry out well between waterings.
here's a link that the "Search" feature here found..

http://http://www.marijuanapassion.com/forum/showthread.php?t=6400&highlight=fungus+gnats
http://www.marijuanapassion.com/forum/showthread.php?t=5538&highlight=fungus+gnats

..that PH probe...check your water before AND after adding the nutrients.
"Filtered" tap water?...what type filter?...some systems use salts that can present problems.

 

[ralph]

Its a Kambrook filter. Contains food safe activated carbons and ion exchange resin to remove chlorine, copper, lead and zinc. It also reduces Turbidity and Lindane. I also let the filtered water rest in the grow room for 24hrs before watering.

The ph probe can not measure liquid, only moist soil.

I plan to add one part hydrogen peroxide (3%) to five parts water for my next watering. (to kill the lavre). i have placed yellow sticky notes near my plant to attract adults. (none have landed 24 hrs, but before placing the sticky notes i capture 3 adults.

I also think the plant needs food. I intend to feed with thrive 27-6-9 (the plant recieved its first doase a week ago and now its in its 6th week.

feedback would be great

thanks

 

[Hick]

hmmmmmm..plants need copper 'n zinc, ..but only in very minute quantities. Your fert "should" provide that. Does the fertilizer have an ingredients list?..Micro/macro nutrients?..
Don't want to "overdo" the mg..it is a salts.
Watch the new growth...that is where your indicators will show. Those old leaves will not repair.

 

[ralph]

So you think that the peroxide will sort the pest? 1 part peroxide (3%) with five parts water. is that ok?

ingredient list of fert
N-27%, P-5.5%, K-9%, S-0.22%,Fe-0.18,Mg-0.5,Mn-0.04,Zn-0.02%,B-0.005, Cu-0.005, Mo-0.002%
(the produxt contains less than 1ppm Lead, 0.5ppm Cadmium and 0.2 ppm Mercury.

 

[Hick]

I don't think the peroxide will harm anything, with a single dose. Though if your sticky traps aren't catching any bugs, they may not be in sufficient numbers to be an issue. I would just watch the traps for adults and treat if needed.
Ferts look like a full spectrum nutrient. There shouldn't be a need for more epsoms.
Your new growth looks good, I think you're on track. I would feed another 1/2 strength dose next watering, watch the new growth and carry on from there.

 

[KADE]

Peroxide is good for the water..... it sometimes kills helpful bacteria in certain brands of nutes... but the more oxygen the better!

 

[ralph]

Three days ago i watered with food. Since then the new growth is green and looking good. The spotted leaves are slowly dying and falling off.

As you can see in the pics, the top of the main stem is so much taller then the top of all of other branches. As a result of this, the light distance from the top of the plant to the light is about 12 inchs, while the light distance from the tops of the lower branches is about 20 inchs. Will this cause a problem during veg or flower stage? Should i top the plant in the hope of reducing this hight difference?

thanks

By the way i watered today with peroxide (3%) in the water.