Excess Calcium in Organic Mix

[polzek]

In short: top of plants drooping, limeish color leaves, whiteish tips, one or two small dark red spots near some tips).

Is this an excess of calcium?

Bottom and middle plant is normal. No signs of any problems on fan leaves.

Problems started after 2 weeks after topdressed with gypsum, bat guano, malted barley, neem,. Table spoon each per 1cft of soil / tea spoon of bat guano. Added a layer of compost on top and mulched back with pine bark.

Always watering with 2 tea spoons / gallon of molasses as tap water pH is above 8 and molases brings it down to 6,6-6,8.

Bat guano is high in Ca
Gypsum is mostly Ca
Molasses is high in Ca?
Tap water probably also high in Ca?

Did I answer my own question or is there more to it?

 

[Teddybrae]

How old are yr plants? Indoors? The problem is most likely with your 'top dressing' because the growing part of the plant is affected.

I 'm wondering what made you top dress with the ingredients you did?

Gypsum won't provide Ca unless the pH for yr plant is correct. So it's Ca-providing effect will be intermittent.

What's the pH of yr soil? Have you a soil pH Test Kit? Cheap.

But altogether, Gypsum, Guano = Alkaline. Malted barley = acid. Mix up!


And get rid of the Pine Bark. More acid! Find a 'gentler' mulch. Rake up some leaves, maybe.


Continuous Molasses is not good. I would worry about it blocking up capillaries in the soil if it accumulated and dried out. Find another pH buffer for yr water.

What is your source of Magnesium?

How do you water? If you water a little then the 'top dressing' may have made a crust on top that's blocking vital oxygen to the roots.

And It is advisable with high-pH water to water a lot and leave it go for a while. That way there's less chance of salt build up.

I think what may be happening is that yr Gypsum is combining with certain minerals in the soil and carrying them away when you water. Or it is carrying enough away to upset the pH balance in yr soil.

(This is a magical ability of Gypsum ... to bind with minerals and make them water soluble. When the sea flooded Dutch fields in the 1950's large amounts of Gypsum were applied. The salt in the soil bound to the Ca in the Gypsum and the following rains washed the soil clean. So that's what Gypsum can do.)

Remove the top dressing if you can. Flush your soil with LOTS and LOTs of water. Do a pH test to find out where yr at.

Then you can feed again.

 

[polzek]

Hi,

Thank you for help!

soil pH is 6.8

I never water till runoff, never had problems.

I always use pine bark, never had problems.

I guess I received bad info regarding how great it is to up the Ca with gypsum.

I always top dress before flip to 12/12 with the same amendments, the only difference this time is malted barley.

18 days 12/12 today.

I use zeolite and kelp in the base mix, never had issues with mag on anything.

Not drooping anymore but newest fan leaves are limeish green, burnt tips, random necrotic spots near tips too but only a few.

Maybe barley caused a pH imbalance?

The plants dont seem to be getting worse.

 

[Teddybrae]

The Barley and the Pine Bark will acidify. The Gypsum is 'selecting' minerals and is carrying them thru yr soil causing an imbalance.
Water well, sounds like yr plant will survive ...
End.

 

[polzek]

I understand, thank you for helping. Will be careful with both.

 

[paradoxlost]

How old are yr plants? Indoors? The problem is most likely with your 'top dressing' because the growing part of the plant is affected.

I 'm wondering what made you top dress with the ingredients you did?

Gypsum won't provide Ca unless the pH for yr plant is correct. So it's Ca-providing effect will be intermittent.

What's the pH of yr soil? Have you a soil pH Test Kit? Cheap.

But altogether, Gypsum, Guano = Alkaline. Malted barley = acid. Mix up!


And get rid of the Pine Bark. More acid! Find a 'gentler' mulch. Rake up some leaves, maybe.


Continuous Molasses is not good. I would worry about it blocking up capillaries in the soil if it accumulated and dried out. Find another pH buffer for yr water.

What is your source of Magnesium?

How do you water? If you water a little then the 'top dressing' may have made a crust on top that's blocking vital oxygen to the roots.

And It is advisable with high-pH water to water a lot and leave it go for a while. That way there's less chance of salt build up.

I think what may be happening is that yr Gypsum is combining with certain minerals in the soil and carrying them away when you water. Or it is carrying enough away to upset the pH balance in yr soil.

(This is a magical ability of Gypsum ... to bind with minerals and make them water soluble. When the sea flooded Dutch fields in the 1950's large amounts of Gypsum were applied. The salt in the soil bound to the Ca in the Gypsum and the following rains washed the soil clean. So that's what Gypsum can do.)

Remove the top dressing if you can. Flush your soil with LOTS and LOTs of water. Do a pH test to find out where yr at.

Then you can feed again.

Gypsum has no affect on pH and is a salt. It doesn't bind with minerals and leech them out of the soil. Na has a large ionic radius. Calcium has a very small ionic radius. Since gypsum is a salt and soluble at most normal pHs all the calcium out competes sodium for the cation exchange site since it is more electronegative. If there was lithium in that water instead of sodium this wouldn't have worked. Its not like gypsum is a chelator.