Is this N deficiency?

[pegz]

Test your tap water.

 

Use baking soda if you have nothing else.

[simonH]

How about dolomite lime, mix it in with the soil? And use baking soda in the water and water plants with it yeah?

 

Tested pH of water, its 6, so slighly acidic

Edited October 5, 2013 by simonH

[asterisk]

Yeah I added a few sprinkles of used coffee grounds when they were going yellow, thinking it would add more N as I though initially thats what it was!

You're spot on coffee grounds are a grat source of nitrogen. Unfortunatly they need to be properly composted first for the nutrient to become available.

 

Just went to bunnings and bought that $10 pH meter....

 

tested pH in a few parts, all below 5

 

In the pure potting mix its just above 6.

 

How can i raise the pH of my mix easily and quickly?

A ten dollar meter wont be reliable. Especially if it's a skewer type unit that is designed to be stuck straight into soil - they're rubbish. You want the sort that has a globe on the end. But as Frank said you will need to mix some soil with distilled water, let it sit, strain it and then test the water. This will give you a very accurate reading IF you have a good quality meter. In your case this isn't necessary though.

If you want to invest in a fancy meter then go ahead - they're fun to use but a powdered Soil pH test kit, while a little subjective, will be accurate enough to keep you out of trouble while growing in soil.

 

What to do now though ey? It's a bit tricky adding something else to bring it back up. and as far as i know there is no quick fix.

Pegz advice of adjusting the water pH wont affect the soils pH enough to be useful (if at all).

 

This is what i'd be doing: VERY carefully remove the seedlings from the soil they're in and transplant them to into fresh, straight potting mix. It will take em a week or so to recover and continue growing but they will. And like others have said you've been over watering so take it easy with the can.

 

Make sure to keep us posted bro. I'm looking forward to seeing some dope ass plants!

Edited October 5, 2013 by asterisk

[simonH]

Thanks man. Yeah I can see how a $10 meter wont be super reliable, but for ballpark use? Can you recommend a good meter (link?)

 

Ill head down tomorrow and get a pH soil test kit, so lets see if that help.

 

I wonder what made it so acidic? When I used the cheap meter, the straight potting mix (organic, designed for veges etc, made by Miracle Gro) gave a reading of around 6, which seems alright, and my mix was just under 5, which correlates with what we've been thinking. I wouldn't think worm castings and compost would be acidic would they, as I've heard of people growing in straight castings and perlite for drainage.

 

Hopefully the plants I'm growing in Coco and using hydro nutrients should give me a better result. I used Brunnings Coco-Peat Brick, as it was the only one I saw that didn't have fertiliser in it. Is this OK, same as Coco Coir - http://www.brunnings.com.au/products/factsheets/easywetta%20CoirPeatBrick.pdf

 

I've also filled a few buckets with water and lewtting them sit overnight, and will water plants with that from now on. Read the Cl in the water is bad for plants.

 

I'm just concerned also why this is happening, as its a pure organic grow, so pH shouldn't be too much of a concern at all, let nature look after it, and many people report amazing results from castings.

 

As far as the coffee grounds, Ill feed them to the worms!

Edited October 5, 2013 by simonH

[nebula420]

don't use a cheaper meter, it's pointless. a good meter can easily cost upwards of $200. unless you can afford otherwise, i'd go with the ph kit as someone else suggested. your local hydro store should have one.

 

coffee grounds will guaranteed lower the ph. lime is good for raising it, just b careful not to add to much or you burn the roots of your seedlings.

 

just because youre growing organic doesnt mean your ph will be right for canabis. the ph for natural forest soils exist across a range, not just the optimum for ganj. keep in mind that as organic matter breaks down, it becomes acidic. so your idea that compost wouldnt be acidic is based on a false assumption. for that very reason, when you using a compost bin, it is advised to add lime from time to time to raise the ph and stop it from becoming overly acidic.

[simonH]

Thanks for the help guys

 

Last night I transplanted it into a bigger pot using potting mix and perlite for extra drainage and watered a lot, so the mixture was like mud, and it drained away.

 

This morning the leaves of the plants had curled down and under. I assume this is shock, and a few days without watering it should pick up again?