Soil Amendments

[digital686]

Hi everyone,

I grow Atlantic Giant pumpkins. I recently had my patch soil tested (getting ready for next year). My calcium is at 1302ppm and it needs to be at 2500ppm. I could add gypsum to the soil but I am concerned that it will raise my sulfur levels. The sulfur level is at 35ppm which is in the high range. My patch is 350 sqft so I would have to add aprox 80 pounds of gypsum. Would this cause the sulfur level to rise a lot? if so what is a good calcium substitute that will not raise the sulfur levels? Thanks for your help.

If you need to see my soil report it is at the link below, ninth post down.

http://www.midnightgardenerblog.com/forum/m-1255821675/

[Ron B]

You got no recommendations with the report?

[digital686]

just to add a little nitrogen. Atlantic giant pumpkins suck up the calcium. I need to get it to 2500ppm.

[Ron B]

What about dolomitic limestone or even hydrated lime?

[digital686]

Those will change the ph of the soil. The ph is ok and does not need to be changed.

[Ron B]

Maybe spray the plants with a calcium solution. Otherwise, it takes a ton of lime to change the pH even one point. Perhaps it is possible to get the calcium up to at or near where you want it without sending the pH of the scale.

[Grant Gussie]

It is not possible to add calcium (which is a cation) without also adding a corresponding anion.

That is unless you want to do the extremely expensive and insanely dangerous thing of adding powdered metallic calcium to your soil (and watch it blow up).

Otherwise, you are going to change your soil chemistry in other ways than just adding calcium. It cant be helped. So you can add calcium sulphate (gypsum) which will add sulphur, or add calcium carbonate (lime) which will add carbonate, or add calcium phosphate (bone meal) which will also add phosphate, or add calcium chloride, which (you guessed it) will also add chloride.

Now your soil test seems to indicate that you have no chloride at all in your soil, which is to say the least, odd. If this is accurate, the obvious answer would be to add calcium chloride. It is generally not sold in bulk for agricultural use, but it is a cheap chemical sold as a deicing salt. But it is a salt, and a very soluble one at that, so my first choice would still be to add bone meal instead. It releases its calcium very slowly and gently. A mixture of lime and bone meal would be OK too (and significantly cheaper) as lime does not raise pH by much except in very acidic soils. In near neutral soils, its relatively inert.

[digital686]

Originally Posted by Grant Gussie

It is not possible to add calcium (which is a cation) without also adding a corresponding anion.

That is unless you want to do the extremely expensive and insanely dangerous thing of adding powdered metallic calcium to your soil (and watch it blow up).

Otherwise, you are going to change your soil chemistry in other ways than just adding calcium. It cant be helped. So you can add calcium sulphate (gypsum) which will add sulphur, or add calcium carbonate (lime) which will add carbonate, or add calcium phosphate (bone meal) which will also add phosphate, or add calcium chloride, which (you guessed it) will also add chloride.

Now your soil test seems to indicate that you have no chloride at all in your soil, which is to say the least, odd. If this is accurate, the obvious answer would be to add calcium chloride. It is generally not sold in bulk for agricultural use, but it is a cheap chemical sold as a deicing salt. But it is a salt, and a very soluble one at that, so my first choice would still be to add bone meal instead. It releases its calcium very slowly and gently. A mixture of lime and bone meal would be OK too (and significantly cheaper) as lime does not raise pH by much except in very acidic soils. In near neutral soils, its relatively inert.

Thanks for the response Grant. I said the same thing to the person that recommended adding the gypsum. He said that extra sulphur was ok because Atlantic giant pumpkins can take a lot of sulphur. Problem is, he cannot tell me in measurable values what "a lot" is.

[fourd]

Curious about calcium nitrate? AGs requires nitrogen for early growth stage but after fruit sets, nitrogen is undesirable. What I don’t know if the nitrate is depleted but that time?

OK, most competitive AG growers do use gypsum. Believe desire PH for AG is around 6.5 -- Gypsum lowers PH, lime raises PH so seems a combination can ballance things out.

Most soils have plenty of calcium but it can be locked up (unusable by plant) -- the trick is making it usable. The PH as well as K and Ma can lock up calcium, believe the desired rate with AGs is 60-80% Ca, Ma 10-15% and K 4-8% or something like. Competitive AG growers want extended 120+ days growth in the fruit but available calcium is quickly depleted, maybe in first 40 days in this big fruit. I think you’ll find many supplement with liquid calcium at that point. Also, I understand the phosphate in bone meal can adversely affect mycorrhizal colonization? AG growers rely heavily on mycorrhizal to process otherwise locked up calcium that can then be used by the plant.

Just my take ... I'm still learning from Ron!

[Millet]

Calcium Nitrate (CaNO3) is a water soluble form of both calcium and nitrogen. When using CaNO3 both the nitrogen and calcium are immediately available to the plant. Therefore, as the season progresses, if additional Ca or N is required applying CaNO3 raises the root zone level very quickly. I also grow both the Atlantic Giant and Goliath giant pumpkins. - Millet (1,158-)

[fourd]

Millet or Ron, I believe you checked out digitals soil test, and I see a couple things there, BUT as I scanned down, what about that brew they got going on??? Won't that kill plants? I'm thinking it is more a crown rot inoculant .... a worm killer ... but maybe a good compost starter? What do you think?