Magnesium Deficiency? Need Some Quick Advise, Please Help!

I need some advise quickly so that I can course correct and get back on track. Some info on my grow. Outdoors in tropical location. 1 gal. pots with Fox Farm Ocean Forest. Using Fox Farm's nutes (Grow Big, Big Blooms, Tiger Blooms). High Humidity. Plants are Afghan Kush Indica. Watering with very hard tap water that rests for 24 hours.

First the deficiency pics (or something heat stress, over watering, pH imbalance, lockout???) I've got small brown spots with yellow veins, some heavier brown spots in places, with a little cupping of the leaves and leave tips curling up. This is mainly happening to the older middle and lower fan leaves...



A quick history of what I have been doing. Plants were in veg 2 or 3 weeks. This is my first grow and I wasn't counting, mistake I know. I was using Fox Farm's Grow Big 2 tsp. per gallon twice a week feeding. Everything is fine at this stage. I go to the Philippines for 11 days and come back to both plants in flowering. I don't know how long they have been in flower mode, but here are the pics when I return from the Philippines. Buds are puff ball stage so how many weeks flower? One or two is my guess.

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So fast forward another 3 weeks to the deficiency pictures. I am guessing I am at the end of 4 or 5 weeks of flower depending on how many weeks of flower it takes to get to the puff ball bud stage. In the last 10 days I upped the nutes. I was using the Grow Big, Big Blooms and Tiger Blooms at half strength. I've feed 3 times in the last 10 days and also we've been getting daily rain, sometimes heavy with winds. Too much water? Nute burn? Magnesium deficiency? Something else? Here are the current pics at 4 or 5 weeks flower...



So the last two days I have flushed the two plants with FloraKleen. First day 1 tsp. per gallon, second day 1.5 tsp. per gallon. I think I have a magnesium deficiency. Shouldn't be calcium as our tap water is mega hard. Lots of rain and wind over the last 10 days. I don't know the pH of my soil, getting a pH meter tomorrow asap. Guys I think I only need 3 or 4 more weeks to bring in the harvest so please help if you can. I'll be watching the trichomes with my 420 scope, but I don't want choke right near the end.

1. What's my deficiency or something else?
2. What week of flower would you guess I'm in. I'm 3 weeks from the puff ball bud pics.

Finally some amateur bud porn from a first time grower...



Thanks in advance for any help...

TropicalGrow

Bumping this due to image file problems that I fixed. Please help if you can...

looks like more calcium and magnesium.

Add lime to the soil.

Flushing is not a good idea unless you have toxic salt buildup. You wash away what nutrients are available as well as amendments in the soil that help buffer pH.

Hard water calcium is good for buffering acid nutrients. Not good for buffering soil pH.

Cannabis uses a LOT of calcium during flowering. Most likely, the ca that was originally in the soil has washed out. This makes the soil unable to buffer and leads to acidic environments and lockout. Adding nutes at this time often causes more problems as the acidity and salt buildup get worse.

MYOB said:

looks like more calcium and magnesium.

Add lime to the soil...

Click to expand...

The plants are only in 1 gallon pots, so it would be kinda hard to work it into the soil at this point. Can I sprinkle it on top and water it in? Or can I put a couple tsp. in a gallon of water and dissolve it and pour it in over a few days?

Thanks again...

Yep, just do that. It's good to have all the lime mixed in with the soil when you start (if you know you need it), but it will still work if you apply it to the top now.

It will slowly become soluble as nitrate producing bacteria raises the free nitrate level of the soil and the calcium balances this.

What MYOB is saying is correct. Cannabis uses a ton of calcium during flowering.

You see washing off will really won't be a good idea..it will drain off every single important nutrient in the soil..instead add some quality fertilizers which will assist the plant in better growth..

It's your Ph i went thru this one before,but it's definitely not magnesium,but it may be a mixture of calcium,potash,and manganese which some people mistake as magnesium deficiency.Get used to spraying your plants daily(water+light fertz/then water alone) until you lower that Ph.

That's my next step tomorrow. Get a pH meter and pH my soil. I'm still learning. Just hoping I can bring home the harvest. I think I have 3 or 4 weeks to go. I haven't smoked any weed since July, 2010. I've been a good boy for 3 years. I'm ready to get baked. Will be trying out a vaporizer for the first time also. Got a Magic Flight Launch Box waiting in the wings...

I'd say instead of getting ph meter get dyna-gro mag-pro or any alternative calmag supplement. And feed as recommended on instructions. I kind of doubt that these colas are 2 weeks old... looks like 3-4weeks to me..

manganese like other trace elements deficiencies appear on top leaves, middle-bottom leaves show ca,mg,n,p,k,s defs.
There is a lot of mg in the soil but it gets locked out by other elements thats why at week 1-2 into flowering you need to start supplementing it until the harvest.

Plants are either 4 or 5 weeks into flower. My dumb ass didn't count. In my defense, I left for an 11 day trip (plants in veg) and when I returned the plants were at the stage of pics 5, 6 and 7. It's been 3 weeks since I took pics 5, 6 and 7. Pics 8, 9, 10 and 11 are from yesterday. A solid 4 weeks and maybe as much as 5 weeks flower.

Today I added 2 tsp. garden lime to each plant and worked it into the topsoil and watered the plants. Garden lime should add calcium, magnesium and adjust my soil pH up. Then I read the pelletized garden lime is slow release, maybe two weeks to take hold in the soil. So now I have a gallon of tap water resting with 1 tsp of garden lime dissolved (hydrated lime) into the water. I will water with that tomorrow to get the calcium, magnesium to the plants quicker and adjust the pH quicker.

Good plan or am I about to fuck up? As soon as I get this problem solved, I will return to my Fox Farm nutes at 1/4 strength...

simisimis said:

I'd say instead of getting ph meter get dyna-gro mag-pro or any alternative calmag supplement. And feed as recommended on instructions. I kind of doubt that this colas are 2 weeks old... looks like 3-4weeks to me..

manganese like other trace elements deficiencies appear on top leaves, middle-bottom leaves show ca,mg,n,p,k,s defs.
There is a lot of mg in the soil but it gets locked out by other elements thats why at week 1-2 into flowering you need to start supplementing it until the harvest.

Click to expand...

Mag pro contains no calcium. Their grow and bloom formulas do but I still start wil botanicares cal mag + to get my tap water around 150 ppm

I wish DG made a cal mag product. I use other products in their line and have been very happy with the results.

I'm in Guam and haven't seen any cal mag products. Will have to hit up eBay for the next grow. I did see some Botanicare products the other day. Will have to go back and investgate them. I also saw pH Up and pH Down. I've got a lot to learn...