Magnesium Deficiency problem, help.

[Rattrap]

Hey all
Well my lightstorm are coming up on their 4th week of flower & as the last run i'm hitting a mag def. I've been feeding them EJ microblast since rooting & i hoped that it would be suficient but it's looking like its not going to be enough Mag.
What i want to do is boost the mag levels with epsom salts but i have no idea how much is too much. I'm growing in standard potting mix & perlite & i'm using organic nutes. I also have a different strain at the same stage of flowering but with no sign of mag def.
What is the best mix rates of epsom salts?
Any help would be really apreceated.
These purple girls really eat the Mag!

 

[Rosy Cheeks]

I've never grown with EarthJuice so I cannot say if there's a lack of Mg in it. The Mg deficiency growers sometimes experience is often not due to lack of Mg (or too much calcium), but either because of a too low ph (that causes Mg lockout) or a too high nutrient concentration (EC), which also diminishes Mg availability. Adding Epsom salt (in this case) takes away the symptome (of Mg def) and makes the leaves green again, but do not cure the illness, which is a too low ph or a too high nutrient concentration. Overdosing Mg is concidered harmless by many growers, but it can cause Ca lockout, which you don't want, especially in flower.

 

[Rattrap]

Hey rosy cheeks,
I never thought of too high EC as the possible cause. The soil PH should be fine, i measured the PH of the runnoff a couple of weeks ago & it was good. My starting water had a PH of 6.5 & the runnoff had a PH of 6.1.
I have been feeding them pretty full on since they have been in flower. Perhaps a really good drink of straight water would do them the world of good. As well as a folar feed of Mag?

 

[Rosy Cheeks]

A too high nutrient concentration could be the cause. More likely with chemical ferts rather than organic ferts like EJ, but still possible, either from too high calcium or potassium levels. What often happens is that in flower, growers drastically increase K levels, which in high doses can suppress the plant's uptake capacity of Mg. If you foliar feed Mg, you will bypass the problem and give the plant exactly what it needs, more Mg. If you cut down slightly on Ca and K levels and the problem pans out, you will know for sure what the problem was. A dash of clear water every now and then will only do your plants good, but don't starve them in early/mid flower, when they need high doses of flower nutes for the budding.

 

[Rattrap]

OK, well i gave them a good drink of water today. I use 30L pots & first gave them 9L of water & collected some runnoff to measure. My starting water had a PH of 6.7 & a TDS of 60. The runnoff had a PH of 6.4 & a TDS that was off the scale! So i gave them another 9L of water each & the TDS droped to 1600. I think the nutes in the potting mix might have been a little too srtong. lol. I also gave them a folar feed of epsom salts at the same time. It'll be interesting to see how the come up. I'll be giving another folar feed in 3 days time & water them again probably in around 4 days time.
Thanks for your help rosy cheeks.

 

[inc0gnit0]

The Epsom salts will fix her right up. I had the same problem a while back. Took a while to get the dosage right but once I did cleared it up in days.

 

[Closet Funk]

Mg def is the most common in indoor grows. Check out Espomas Epsom Plus (0-0-22) it had Mg, Calcium, and K.

 

[irie-i]

hey rattrap.... how did it go? did you spray w/ epsom salts? how much?..cervantes' guide says 2% solution of epsom salts. i guess thats like 20ml per liter. i think i have a Mg definciency too. brown spots on some of the leaves, and the little blades at the leaf edges are browning too. im in week 4 of flower, i guess its okay to spray epsom salts on the flowers????

 

[Rattrap]

Hey irie,
i sprayed them with an epsom salts mix of 1 teaspoon to 1 Liter of water. I also gave them a feed of Earth Juice microblast with a couple of teaspoons of epsom salts added. So far no change but i don't think its gotten any worse either.
Irie, i might be wrong but i've never thought of mag def as showing itself as brown spots & a browning of the leaf edges. In my mind mag def shows up as yellowing of the leaf in between the leaf veins while the leaf veins stay green. Eventually that yellowing spreads out till the whole leaf is yellow. It also usually starts showing up in the middle of the plant. If i'm worng someone please correct me.

I've tried to take a couple of pics to show u my mag def, tho my camera isn't the best for close ups.

 

[aeric]

That looks like N deficiency.

Irie: spray leaves only, preferably underneath

 

[Verite]

Imo if they have had microblast since having roots and all the excess you have been giving it is probably too much mag.

Also that last pic is showing signs of a ph issue, krinkled mottled leaves with patterns and a hard feel are symptomatic of ph issues.

I looked up what microblast has in it and would not use it solo and would not use it often. It kinda reads like its boosted in all areas to correct deficiencies meaning to use it often might be too much in one or more areas of trace nutes as they all effect each other in uptake based on ph.

Heres a link with the microblast info.
http://www.greenfire.net/hot/J075.html

Heres a farm related info on soil and nutes that should get your braincog cranking. Understanding what your working with helps master the harder parts.
http://www.farmtested.com/56.html

Heres one of their better charts showing the basis for nutrient interaction in soil.

 

[narniachronic]

very helpful chart, thanks verite!!

 

[turtle power]

Looks like a kalium defiency to me... The most common deficieny during flowering and often mistaken with N defiency.

A N defiency drains the nutrients from the top of the leaves to the back..

A kalium defiency drains the nutrients from the sides of the leaf to the middle.

offcourse both can happen at the same time and is harder to spot.

What i would do... Add pk 13-14 if you have it to your regime to add extra kalium and phosfor which they need alot of.

Secondly spray your flowering nutrient onto the leaves of your plants which are infected or the whole plant is ok too. You will see that they will become greener again. Keep spraying or increase your nutrient dose.

Looks like this plant needs more nutes then your other plants

Taken a complete plantpic gives also a better idea of the situation to see whats happening on top... What flowering fert are u using and what are the % NPK it contains?

 

[MTF-Sandman]

Kalium = Potassium?

 

[Rattrap]

I'm using a home brewed chicken poo tea. I think my problem stems from the TDS/EC being way too high causing all sorts of lockout. I gave them another big drink of watera couple of days ago & got the TDS down to 500. Since the last big water i've started folar feeding them with bio-juice bloom. Tommorow i will be watering them again, this time with medium to weak tea.
Has anybody ever measured the TDS/EC of their runnoff water? I'm talking from potting mix here.
Its always hard to tell how strong the nutes are in potting mix & i have a bad habbit of being heavy handed.

 

[Verite]

Is the chicken shit all you are using?

Its always hard to tell how strong the nutes are in potting mix

What kinda of potting mix do you use?

 

[Rattrap]

In veg & first 2 weeks of flower i used my tea with some seasol & EJ microblast.
In weeks 3 to 6 of flower i plan to use half strength tea with some bat guano & EJ microblast.
My potting mix is dynamic lifter organic potting mix (no slow release ferts) 2 parts, 1 part mushroom compost & 1 part perlite all in 30L pots with a singe tap per pot for runnoff tho with 4L per watering there is little runnoff so i keep the taps closed. I give them 4L of water of nutes aprox every 3-4 days depending on the moisture meter.
I started them on the tea at a rate of 20:1 then uped it to 10:1 when they went into flower. But i think the nutes are stronger than i thought & i was giving it to them too often. At least thats how i'm treating the problem at the moment.

When i saaid, "Its always hard to tell how strong the nutes are in potting mix", i was refering to how much nutes are retained in the soil after feeding.