adjusting ph of soil in growbox

[ktm250]

I might need to adjust ph levels in my soil,im not sure.Heres the deal - The pic has 4 pots in it but i only have 1 seedling in one of the purple pots and one in the big brown pot(seedlings are only 13 days old).I have a soil ph tester with the probes on it from bunnings that says the ph in the brown pot is in between 6.0 and 7.0,so about 6.5.In the small purple pot its ph is about 7.1.

I was under the impression that cannabis like neutral ph of 7.0ph but have read also that they like 6.0 to 6.5ph.So which is it?

In the pic the 250watt light is really close but have moved it way up high now.Which is the best way to adjust the ph levels in my situation?Do i use fine dolomite lime?Sulfer?Egg shells?And how do i use it?

Also i bought a fan speed controller to cut some of the noise down from one of the 120mm sunon fans im using(intake fan).The light and ballast and two fans plus fan speed controller is connected to a 4 socket powerdboard connected to an extention cord that runs from the house into the shed where my growbox is.Please let me know if that could be a fire hazzard also.Cheers.

P.S. I also have put 3/4 of teaspoon of once a year slow release fert on top of soil aswell.It has a total nitrogen of 17 per cent.Should i use the mericle grow i bought yet or wait a while?

Edited August 28, 2007 by ktm250

[Token Jet]

One lead should handle that no worries at all. The timer is usually the weakest link. To adjust my ph I use ph raise or lower as purchased from the hydro shop. Try diluting it with water then water your plants with it. I've heard some people say 5.2 and others say 6.5. I guess you'll just have to see what works for you. Like the skateboard trolley.

[67Special]

Dolomite is good for raising ph with the added bonus of magnesium, but imo you should be aiming for 6.5 so your after ph down.

 

I dunno how accurate your bunnings probe is, but you could always cross-check it against a soil test kit which are very reliable, Manutec is a common one, costs about $30.

 

Egg shells won't affect ph much, but they're a good source of calcium, so just crush em up as fine as you can, I use a rolling pin

 

I wouldn't be adding more nutes until they get going a bit, watch em closely and they'll show you when they need more.

Have you found a deficiency guide for mj yet, one with good clear pics is at least as valuable to a grower as ph tests imo.

 

Good luck with em 250

[loylty gets u nothing]

sounds like id be leaving it alone

them readings may not be the most accurate too

usually a good store purchased soil will have a general ph of nuetral

MJ will thrive in it..have u got some food for it in flower??

as it will chew threw the nutes available in the soil within the vege period imho

all the best

billo

[ktm250]

Thanks for the info guys,i was thinking about that hydroponic ph up and down but thought it was just for the hydro`s with the resovoure.I will get some flowering nutes when there bout to flower.Just put some panda film on the walls too.I also wacked in some snow peas and strawberries in the growbox aswell hehe.Those snow peas are growing twice as fast as my mj plants.

 

The last few days its been hitting about 18 degrees outside so its making my box get to about 34 degrees at about 12pm.I have my timer set for 9pm on and 3pm off but im going to change this to 5pm on and 11am off so its cooler.Should i keep it at 18hours on for the hole time in veg then change to 12/12 for flowering or should i go down to 14 hours on when plants are about to 2nd node?

 

Also the stems on my 13 day old seedlings are very long(about 10cm)does this seem normal?Because i have only grown mj outside before and they never got that long.Usually the stem would be about 5cm long while having the second set of jagged edged leaved coming out.Mine are just starting to get there second set.

[loylty gets u nothing]

sounds to me they are stretching for the light

how far and wat light u got?how far away is the bulb?

 

250 sorry ..raed above bill

wat are u sing for exhaust??

sounds a bit hot in there imo

18/6 for vege

12/12 for flower and id grow em a bit more than 2 nodes before flowering

as ya yield will be affected dramatically flowering prematuraly

all the best

bil

 

with summer coming a centrifugal would be the best option for a new fan

maybe 150mm will aloow u clear ya area pretty quick

[Luke Skywalker]

34c+ is very hot for a growbox with a 250w in there and outside ambients of 18c. What venting you got?

[ktm250]

The light is a 250watt hps and at present it is about 1.25 meter above pots.I put it that high because the soil was drying out very quickly.

 

I have a 120mm sunon fan for intake and outake.centrifugal fans are very expensive on my budget.I would buy another 120mm sunon fan to use as a second outake but they are just too noisy as the growbox is in a small shed right next to neighbours fence.Is there a brand of fan around the same size of mine that is really quiet?

 

I didnt intend flowering at 2nd node,i was just thinking 18hours might only be for germinating then later change to 14hours.But anyway,i will switch to 12/12 when they are about 2ft tall.

 

So,should i lower the light a bit?Here are some pics.1st one is where the light was and 2nd pic is where it is now.Is it close enough?

Edited August 30, 2007 by ktm250

[ktm250]

Since i have changed the light to 5pm on and 11am off,the box hits a max of 25c now.Not 35c as it was through the day.