Soil runoff

[Kingrow1]

No max just lime. I use soil out of the bag nothing else, seedling soil for seedlings and flowering soil for every other repot, use to work fine but now the pH. I have just flushed a plant tonight and it was one of the healthy ones, pH was 6 and ppm 2400 in runoff, put it back down to 500ppm and pH6.6 I must learn to flush on the last watering before repotting so the plants soil is the same as the repotted soil. Technique is all important to solving this pH problem, spending like three hours a night sorting plants at the moment!

 

[Kingrow1]

Yer mort, i won't make the same mistake you made and add too much now i heard your story!lol! Lime is a sod to work with, if it takes time to work why dont i just pour water into my garden lime pot and let it sit a month then scoop out what i needed rather than mixing my soil a month early? Maybe some natural pH up soil amendments might help.

 

[max316420]

get some calmag..... the lime isn't providing it fast enough, I think that is your problem.. We add lime and expect it to supplement instantly but it takes time to break down. You might not be having a ph issue could be they just want a little extra

 

[max316420]

and is the lime actually supplementing enough calmag for lush growth?? We really don't know how much is in there right?

 

[Kingrow1]

Yer, i have left of watering in the powdered lime, it really fixed the problem overnight but at that point i carried on adding it to the soil. I will re-establish watering with the lime to supplement the lime in the soil, just got to wait for the pots to go dry. The flush corrects the pH and the ppm cause the plants grow green again but i wonder just as to how long they will keep their pH. I need to up my lime that is clear but every week younger plants are getting issues. Still need time to work it through with every plant and see how the peat free dose. I am close to using coco or somthing even just to weaken the hold the peat has on the soil. I am seeing results but i still have a lot of work, this truly sucks!

 

[max316420]

I started to get a tad of yellowing even with the lime, I hit one plant with seamag and one with epsom salt and the both completely stopped yellowing.. Just look at the lime as only buffering your ph and not supplementing calmag...

 

[Kingrow1]

I think my cal/mag problems early on were mainly down to low pH, i do add 100ppm epsom salts to my water most waterings now just to get the ppm of my water up. I would say i am providing all the cal/mag they need because not seen any def for a long time. One plant 3 weeks into flower just decided to start getting brown spots over the oldest fan leaves, i never flushed it and now have to kill it off due to having brown spots all over. It also has yellow patches on the leaves exactly like all the pics of pH. If the flushes keep the pH good for a month i will be happy as i am happy to flush once a month, would mean i repotted before flowering and once in flowering with a flush at the end. This is doable if the pH holds in the pots i have flushed, all have had garden lime watered in during the flush too so should help. I just need to find what works with me and then dial it in. Hard work though and never had this pH problem so bad before, like just happened a month or so ago and i wasn't having a single problem before! My soil sucks cause thats the only thing that changes!

 

[Kingrow1]

If i have a decent amount of lime in my soil and added 100ppm epsom salts to all water do you think this would work or would i be giving too much epsom salts?

 

[Wetdog]

If i have a decent amount of lime in my soil and added 100ppm epsom salts to all water do you think this would work or would i be giving too much epsom salts?

IDK ppm, but 1tsp epsom salts to a gallon of water will do you fine. A little goes a long way. Even with lime, I've had to add epsom salts. The mag in the dolo is really slow release, but the Ca seems available pretty quick. I've never used cal/mag, just the mag.

BTW, don't just keep adding lime, one application is usually sufficient. Wetting your 'lime pot' isn't going to do much. LOL Lime needs to be in contact with the soil it's affecting and then moistened.

Remember, it's crushed rock, not a chemical and doesn't really dissolve.

Wet

 

[Kingrow1]

Ok wet dog you might have hit on somthing there, the calcium release's quick but the mag is slow. Is this correct and can you provide a reference if poss? Maybe this is the problem i am getting and it is the mag which is better than buffering the soil than the cal. Hmm this would make more sense and the reason i feel compelled to add epsom salts to the water now and again.

I hit my plants with powdered dolomite lime and it worked quick but this could have been the calcium part of it and i may have been lacking the mag and hence another soil buffer. If i had to answer the question of which buffers the soil better and faster i would have to say magnesium and not calcium, obviously i don't know the answer but if i had to guess which one. Feeling like this is getting a little scientific now.

 

[max316420]

Calcium (Ca)- immobile
Practical Information: Cannabis requires nearly as much calcium as other macronutrients. Avert deficiencies in the soil and in most soilless mixes by adding fine dolomite lime or using soluble-hydroponic fertilizers containing adequate calcium.

Technical Information: Calcium is fundamental to cell manufacturing and growth. Calcium is necessary to preserve membrane permeability and cell intergrity, which ensures proper flow of nitrogen and sugars. It stimulates enzymes that help build strong cells and root walls. Cannabis must have some calcium at the growing tip of each root.

Deficiency: Calcium deficiency is somewhat uncommon indoors, but is not uncommon in fibre hemp. Frequently, plants can process more calcium then is available. It also washes out of leaves that are sprayed with water. Deficiency signs may be difficult to detect. They start with weak stems, very dark green foliage, and exceptionally slow growth. Young leaves are affected, and they show signs first. Severe calcium deficiency causes new, growing shoots to develop yellowish to purple hues and to disfigure before shriveling up and dying; bud development is inhibited, the plants are stunted, and harvest is diminished. Growing tips could show signs of calcium deficiency if the humidity is maxed out. At 100% humidity, the stomata close, which stops the transpiration to protect the plant. The calcium that is transported by transpiration is immobile.

Treat deficiencies by dissolving one-half teaspoon of dehydrated lime per gallon of water. Water the deficient plants with calcium-dosed water as long as the symptoms persist. Or use a complete hydroponic nutrient that contains adequate calcium. Keep the pH of the growing medium stable.

Progression of deficiency:
- Slow growth and young leaves turn very dark green.
- New growing shoots discolour.
- New shoots contort, shrivel and die.
- Bud development slows dramatically.

Toxicity is difficult to see in foliage. It causes wilting. Toxic levels also exacerbate deficiencies of potassium, magnesium, manganese, and iron. The nutrients become unavailable, even though they are present. If excessive amounts of soluble calcium is applied early in life, it can stunt growth. If growing hydroponically, an excess of calcium will precipitate with culfur in the solution, which causes the nutrient solution to suspend in the water and to aggregate into clumps causing the water to become cloudy(flocculate). Once the calcium and sulfur combine, they form a residue(gypsum) that settles to the bottom of the reservoir

 

[max316420]

Magnesium (Mg)- mobile
Practical Information: Marijuana uses a lot of magnesium, and deficiencies are common, especially in acidic(pH below 7) soils. Adding dolomite lime to acidic potting soils before planting will stabalize the pH, plus it will add magnesium and calcium to the soil. Add Epsom salts with each watering to correct magnesium deficiencies, if no dolomite was added when planting. Use Epsom salts designed specifically for plants rather then the supermarket-type.

Technical Information: Magnesium is found as a central atom in every chlorophyll molecule, and it is essential to the absorption of light energy. It aids in the utilization of nutrients. Magnesium helps enzymes make carbohydrates and sugars that are later transformed into flowers. It also neutralizes the soil acids and toxic compounds produced by the plant.

Deficiency: Magnesium deficiency is common indoors. The lower leaves, and later middle leaves, develop yellow patches between dark, green veins. Rusty-brown spots appear on the leaf margins, tips, and between the veins, as the deficiency progresses. The brownish leaf tips usually curl upwards before dying. The entire plant could discolour in a few weeks, and if severe, turn a yellowish-whitish tinge before browning and dying. A minor deficiency will cause little or no problem with growth. However, minor deficiencies escalate and causes a diminished harvest as flowering progresses. Most often, magnesium is in the soil but is unavailable to the plant because the root environment is too wet and cold or acidic and cold. Magnesium is also bound in the soil if there is an excess of potassium, ammonium(nitrogen), and calcium(carbonate). Small root systems are also unable to take in enough magnesium to supply heavy demand. A high EC slows the water evapouration and will also diminish magnesium availabilty.

Progression of deficiency:
- No deficiency symptoms are visible during the first 3-4 weeks.
- In the 4th-6th week of growth, the first signs of deficiency appears. Interveinal yellowing and irregular rust-brown spots appear on older and middle-aged leaves. Younger leaves remain healthy.
- Leaf tips turn brown and curl upward as the deficiency progresses.
- Rust-brown spots multiply and interveinal yellowing increases.
- Rust-brown spots and yellowing progress, starting at the bottom and advancing to the top of the entire plant.
- Younger leaves develop rust-coloured spots and interveinal yellowing.
- The leaves dry and die in extreme cases.

Treat deficiency by watering with 2 teaspoons of Epsom salts(mangesium sulfate) per gallon of water. For fast results, spray the foliage with a 2% solution of Epsom salts. If the deficiency progresses to the top of the plant, it will turn green there first. In 4-6 days, it will start to move down the plant, turning lower leaves progressively more green. Continue a regular watering schedule with Epsom salts until the symptoms totally disappear. Adding Epsom salts regularly is not necessary when the fertilizer contains available magnesium. Use a foliar spray of Epsom salts for a fast cure. Another option is to apply magnesium sulfate monohydrate in place of Epsom salts. Add fine dolomite lime to soil and soilless mix to add a consistent supply of both calcium and magnesium over the long term. Always use the finest dolomite lime available.
Control the room and root-zone temperatures, humidity, pH, and EC of the nutrient solution. Keep root-zone and nutrient solution at 70-75F(21-24C). Keep ambient air temperature at 75F(21C) day and 65F(18C) night. Use a complete fertilizer with an adequate amount of magnesium. Keep the soil pH above 6.5, the hydroponic pH above 5.5, and reduce high EC for a week. The extra magnesium in the soil is generally not harmful, but it can inhibit calcium uptake.

Toxicity: Magnesium toxicity is rare and difficult to discern with the naked eye. If extremely toxic, the magnesium develops a conflict with other fertilizer ions, usually calcium, especially in hydroponic nutrient solutions. The toxic buildup of magnesium in soil that is able to grow marijuana is uncommon.

 

[Wetdog]

Ok wet dog you might have hit on somthing there, the calcium release's quick but the mag is slow. Is this correct and can you provide a reference if poss? Maybe this is the problem i am getting and it is the mag which is better than buffering the soil than the cal. Hmm this would make more sense and the reason i feel compelled to add epsom salts to the water now and again.

I hit my plants with powdered dolomite lime and it worked quick but this could have been the calcium part of it and i may have been lacking the mag and hence another soil buffer. If i had to answer the question of which buffers the soil better and faster i would have to say magnesium and not calcium, obviously i don't know the answer but if i had to guess which one. Feeling like this is getting a little scientific now.

Actually, it's the calcium that buffers the soil. Some garden limes have little to no mag in them and are pretty much pure calcium. Other stuff, like oyster shell flour also works good for buffering the soil, but has no mag.

Good post Max, except for one thing. That bit about the epsom salts for plant use rather than the supermarket kind is pure BS. They are exactly the same thing in different packaging, with the one labeled for plant use way more expensive. Just don't get any with added perfumes and such, like for bath use. The label on either should just say pure magnesium sulfate.

Wet

 

[Shwagbag]

Actually, it's the calcium that buffers the soil. Some garden limes have little to no mag in them and are pretty much pure calcium. Other stuff, like oyster shell flour also works good for buffering the soil, but has no mag.

Good post Max, except for one thing. That bit about the epsom salts for plant use rather than the supermarket kind is pure BS. They are exactly the same thing in different packaging, with the one labeled for plant use way more expensive. Just don't get any with added perfumes and such, like for bath use. The label on either should just say pure magnesium sulfate.

Wet

Very good point Wet.... The fast acting lime that I have is smaller granules and is purely "calcitic" lime with no magnesium. "Garden Lime" or "Dolomite Lime" (Not to be confused with the kung fu pimp) are both calcified and rich in magnesium. Something to definitely be aware of depending on the type of lime you choose to work with. Obviously magnesium sulfate would be recommended in conjunction with calcitic lime if you're looking to add mag.

 

[max316420]

Damn I feel like im in science class lol NICE... GOOD INFO GUYS

 

[Kingrow1]

Ok so i see the word hydroponic ferts! I have heard how these are more complete ferts for a soil grow in a lot of situations, do you think it would be better to swap to these as it would supplement my soil better in cal/mag? They are the same price as soil ferts and could easily swap no problems. This could be the answer i need, maybe some hydro canna nutes next!

Good info guys, really thought the thread was finished back there but then a ton more of info hits us!

Wet- So the calicium is better for buffering the soil than the magnesium?

I am slightly confused as to the part where it says if you have no calcium or lime just add epsom salts for the whole grow? Dose this work or won't you still need calcium from somewhere?

Why dosen't epsom salts have calcium in it, would be a lot better than dolomitic lime, stuff takes like 30 secs to dissolve in the water and i can get an accurate ppm with it. I do ec my water up from like 50ppm to 150ppm with epsom salts approximatly, this is good right?

 

[Kingrow1]

I started to get a tad of yellowing even with the lime, I hit one plant with seamag and one with epsom salt and the both completely stopped yellowing.. Just look at the lime as only buffering your ph and not supplementing calmag...

Sorry max i finally understand this as well, am a bit slow today!lol! Good idea and i can watch for this easily.

 

[Shwagbag]

Ok so i see the word hydroponic ferts! I have heard how these are more complete ferts for a soil grow in a lot of situations, do you think it would be better to swap to these as it would supplement my soil better in cal/mag? They are the same price as soil ferts and could easily swap no problems. This could be the answer i need, maybe some hydro canna nutes next!

Good info guys, really thought the thread was finished back there but then a ton more of info hits us!

Wet- So the calicium is better for buffering the soil than the magnesium?

I am slightly confused as to the part where it says if you have no calcium or lime just add epsom salts for the whole grow? Dose this work or won't you still need calcium from somewhere?

Why dosen't epsom salts have calcium in it, would be a lot better than dolomitic lime, stuff takes like 30 secs to dissolve in the water and i can get an accurate ppm with it. I do ec my water up from like 50ppm to 150ppm with epsom salts approximatly, this is good right?

All lime will be calcified to my knowledge. Not all lime contains magnesium. As wet said, it is the calcium that stabilizes PH at or about neutral. Epsom salts will provide magnesium and sulfur, but NO calcium.

 

[max316420]

If your having a mag def, you would only want the mag because over doing the calcium could cause the plant not to uptake other nutrients. But I could be wrong

 

[Kingrow1]

Ok so this is what prompted me to think pH in the first place, a picture from my book called 'Marijuana Garden Saver' by J.C.Stitch and edited by Ed Rosenthal, the only book i have been able to accuratly diagnose plants with.

Next is my worst plant that i have pulled from the flower room, similar i think you will agree, especially the picture directly after it. I know a lot of my leaves look different but belive me they all started out similar to the picture in the book. I don't and wouldn't say i have any other deficiencies etc etc and think my plant just shows pH problems.