Yellow Leaves and Deformed Leaves

[mallett]

High All,

I have noticed a few problems with my plants which are nearly 1 month old and in the veg stage at the moment under 24/7 light ( a 600w HPS) roughly 2.5 feet away from the plants and I was wondering if anyone could advise me.
The plants have been started from bagseed and are currently around 20cm high.
My soil mix is miracle grow multipurpose compost mixed with perlite and stones at the bottom for drainage, all in 5 litre pots.
My space is ventilated with a 10,000 BTU ac unit.
As you can see from the attatched pics some of my leaves have yellow patches on them and the newly forming leaves are yellow also, some leaves haven't formed properly at the tips.
I was using a 15-30-15 fertilizer by mistake to begin with and have only fertilized my plants once with this fert - I put my miracle grow fert in with my water when I water them which is usually once a week.(I used the reccommended mix on the box which I now know isn't advised for the first time)
Today i bought a Lawn feed which is 15-3-3 and I will be using it next time my plants need watering.
This is my first ever grow and I don't know how often and how much I have to fert my plants could anyone advise?
Also if anyone has any ideas why my babies are sick advice would be much appreciated.

p.s I did spill a bit of water on the leaves when ferting could that be why?

Also how can i tell when to start flowering?

Many Thanks in Advance.

mallett

[gonnagrow]

If the soil you are using is multi-purpose compost, I'm assuming it already has some nutrient value. No need to feed as much as you are imho. Whatever the ferts say to mix, start with half or a quarter and see how the plants do before over doing it.

I don't know what your ambient room temp is but I'm guessing even if the room is cool, the plants are hot. Put your hand above the top of any plant and if you feel the heat of the light on the back of your hand, the light is too close. No need to burn them up either.

I fertilize rarley and organically, maybe once a week if that. Miracle gro isn't the best stuff for your plants and you can find blood meal, bone meal and maybe even guanos or manure to fert your soil.

Better to under-fert and make sure the light is a decent distance from the plants at that age. I would suggest bigger pots as well, 1 gallon (5 liter) is a bit small for a good yield, I would say 3 gallon (13 liter) min.

Hope that helps, otherwise looks good keep it up.

Gg

[gonnagrow]

Another note . . I know HPS is good for veg and flower, but the mostly red spectrum increases internodal spacing (space between nodes). You actually want to keep the internodal spacing to a minimum. Increasing blue spectrum with fluoros or Metal Halide helps. Just some info I know we're all on a budget . . .

I veg strictly with fluoros and seems to do well for me. I would rather have a metal halide but thats not an option at the moment.

Gg

[mallett]

I have just checked on my plants and all of the new leaves that the plant is producing are yellow with little green in them.
I haven't watered my plants since over ferting cause my moisture meter still reads from 8-10 (10 being the highest)
I have attatched a picture of one of the plants.
Is this still to do with over-ferting or have I got another problem?

mallett

[mallett]

High Gonnagrow,

Thanks for the good advice bud.

I have just flushed out my 5 litre pots with 15 litres of luke warm water ( ph tested ).

when should I fert my plants next ?

also, what signs should i look out for when my plant is telling me it needs watering?

Many thanks for your support.

peace,

mallett

[gonnagrow]

Looks like heat stress, fert burn or pH fluctuation. Just give them some non-ferted water a couple times and let them rebound.

I always pre-mix ice cold water out of the tap and let it sit overnight to get room temperature and dissipate chlorine. Warm water comes from your hot water heater, which contains sediment and hard minerals etc.

Feel how heavy the pot is when fully watered, when it weighs a lot less than that it needs watering hehe. Honestly thats how I do it when I soil grow.

Gg

[gonnagrow]

Almost forgot . . .

Plant Problem Link

Gg

[mallett]

hey gg,

I am going to get a digital PH meter soon as I only have one of those crappy old non-digital ones!
I'm not gonna fert until they're better and I have a paranoia that it could be heatburn. I have put the two worst ones under my cooltube floro at the moment and will see how they improve.
I have had a few major heat issues up in my attic and room temp around the house is as high as 26 celcius!
With one of my HPS lights running in the attic temps are around 30c+ and with both on my ac unit shuts off at 42c!!!

I really need to cool these lights and am looking into designing a cooltube for both of them.

My AC Unit is a portable one and the back of it gives off so much heat (the exhaust)

My humidity is at 15-20% would a humidifier help temps at all as my humidity was 60% when they were under floros.

Last question... Can you get Cool HPS Lightbulbs that don't give off much heat or am i dreaming?!!!

Thx GG.

Peace,

mallett

[javpanda]

I had this problem its a nitrogen difficency, use a good tomato feed