Diatomaceous Earth as a seed starting medium

[habitat_gardener]

It could also be birds. I've had broccoli seedlings nibbled to a bare stem by birds. The solution is to use row cover until the plants are past the "tender baby greens" stage.

[JLJ_]

Originally Posted by RayR

This experiment started in January when I was wondering how Diatomaceous Earth would work as a seed starting medium. . . . I found that Moltan makes the same DE product sold as an oil absorbent called UltraSorb which I found right down the street at the local AutoZone in a 15lb bag for $5.99. The only difference between UltraSorb and the kitty litter was the granule size, the UltraSorb is a much less coarse granulation (more like coarse sand), which was easier to work with. . . .

Is it correct that these are the same product you are using, but in 5 and 25 lb sizes?

http://www.oreillyauto.com/site/c/de...word=ultrasorb

http://www.oreillyauto.com/site/c/de...word=ultrasorb



I was somewhat puzzled about the dramatic difference in cost per lb, and the fact that the 25 lb bag specified no warranty while the 5 lb bag specified manufacturer's defect warranty. The only defect I could think of that would apply would be if the contents were something other than specified . . .

Also, I noticed that the oreillyauto pages refer to the 5lb bag as part number 0830, but the url for that item shows 8804, which matches the flyer from moltan.com

http://www.moltan.com/Products/absorbentsDE.htm

Not sure if you can shed any light on this, but I knew you had researched it, so thought I'd ask. If I try this I'd like to get what you've already found to work well. And when I began using food grade DE to make life miserable for bugs, I researched that quite a bit and was surprised how many significant variables there were in getting the right DE.

One thing that occurred to me, I did find that food grade DE had been tested and found to be harmless to earthworms, but I don't know about this coarser grade -- did you find anything on that?

[RayR]

Yes, the O'Reilly's parts are correct for Ultrasorb
You can also use Optisorb if you can find it which is the same DE in a coarser grade. Also the Blue Ribbon DE car litter is exactly the same as Optisorb. The larger bags are usually more economical.

The coarser grade DE isn't harmful to anything including insects. Only when DE is finely powdered and dry does it have those sharp razor edges that are harmful to soft bodied insects.

[JLJ_]

Originally Posted by RayR

Yes, the O'Reilly's parts are correct for Ultrasorb
You can also use Optisorb if you can find it which is the same DE in a coarser grade. Also the Blue Ribbon DE car litter is exactly the same as Optisorb. The larger bags are usually more economical.

The coarser grade DE isn't harmful to anything including insects. Only when DE is finely powdered and dry does it have those sharp razor edges that are harmful to soft bodied insects.

I thought your point about the "coarse sand" grade of the Ultrasorb being easier to handle than the larger particles of the Optisorb made sense.

Concerning earthworms, etc. . . . what I was thinking of was the cumulative effect over time of putting it into the garden. Any texture would have bits of various sizes, plus over time in a garden I suspect the larger particles would break down. In fact . . . doesn't the manufacturing begin with grinding what they mine to a fine powder, then manufacturing particles of different sizes?

Even if there was a modest accumulation in the garden that wouldn't necessarily be bad -- I'm sure that somewhere, when researching the food grade DE, I saw reports that areas where DE is a naturally occurring part of the soil have less problems with some "pest" bug critters. But I'd hate to have my earthworms trying to scratch itchy skin -- hard to do if you're an earthworm. [g]

[RayR]

Originally Posted by JLJ_

I thought your point about the "coarse sand" grade of the Ultrasorb being easier to handle than the larger particles of the Optisorb made sense.

The smaller particles are easier to work with when planting small seeds, but regardless both sizes work fine.

Originally Posted by JLJ_

Concerning earthworms, etc. . . . what I was thinking of was the cumulative effect over time of putting it into the garden. Any texture would have bits of various sizes, plus over time in a garden I suspect the larger particles would break down. In fact . . . doesn't the manufacturing begin with grinding what they mine to a fine powder, then manufacturing particles of different sizes?

No, they don't grind it to dust and glue it back together, that would defeat the purpose of it as a naturally absorbent material. It's a pretty stable material in its amorphous state, it's inert and not soluble in water. I wouldn't be concerned with it breaking down, it's been underground for 10 million years or so before it was mined, I think it will last awhile longer in your garden.

Originally Posted by JLJ_

Even if there was a modest accumulation in the garden that wouldn't necessarily be bad -- I'm sure that somewhere, when researching the food grade DE, I saw reports that areas where DE is a naturally occurring part of the soil have less problems with some "pest" bug critters. But I'd hate to have my earthworms trying to scratch itchy skin -- hard to do if you're an earthworm. [g]

I think a modest accumulation is a good thing, the larger aggregates improve aeration.
I don't know about its effects on soil pests, has that been proven or is it anecdotal? I only know the dry fine powder at least annoys pests on leaves, it works similar to kaolin clay as a feeding deterrent.
When you think about all the other sharp particles earthworm must run into underground , not to mention what they ingest when they eat, I don't think a little DE is going to give them itchy skin.

[Redbaron]

Adding DE to soil is harmless to worms.

[JLJ_]

Originally Posted by RayR

. . .they don't grind it to dust . . .

The "DIATOMACEOUS EARTH DESCRIPTION" PDF link on this page at the Moltan site

http://www.moltan.com/Products/absorbentsDE.htm

says:

"When diatomaceous earth is quarried, milled, finely ground, heated, and passed through a screen, it becomes a porous granular product. This is a porous product with microscopic openings, and when magnified, looks like tiny sponges. Clear water can pass through these openings; but particles, as small as one to three microns, are trapped during the first pass through the media."

Which doesn't mean that the products Moltan sells would again break down to the "finely ground" state they were in early in the manufacturing process -- might depend upon the results of that heating -- I believe you observed earlier that the heating for processing this form of DE was dramatically less than that used in manufacture of swimming pool DE. I was considering that the granules might return to the dust state, under garden conditions, and if they didn't, what effect an accumulation of this manufactured granular product might have on the garden.

Originally Posted by RayR

I don't know about its effects on soil pests, has that been proven or is it anecdotal?

It has been several years since I looked into this -- it was before I began using food grade DE to deal with cabbage worms, etc -- when I wanted to be sure it would not hurt earthworms. My recollection is that in that search I ran across a study of one or more sites that found reduction or absence of particular pests in soil naturally high in DE -- near DE mining areas, as I recall. That doesn't mean that the same would be true of DE blended with the soil of average gardens, as the overall composition of the soil, level of natural moisture, etc. would be expected to play a role -- just suggests that an accumulation of DE in garden soil *might* have an effect, and if so, one would want to try to ensure that it was a beneficial effect. (Beneficial from the point of view of gardening primates )

Your seed starting results have been so impressive I am hoping to incorporate DE into my seed starting combinations -- probably in some layered form. Seems likely that this would result over time in introducing more DE to the garden soil than gets there as a result of my DE plant dusting. Still, I suspect that DE accumulation in the garden would not be a problem -- but I try to think such things through in advance -- hard to get it out, once it's in there, if letting it get into the garden soil turns out to be an "oops".

[RayR]

Originally Posted by JLJ_

The "DIATOMACEOUS EARTH DESCRIPTION" PDF link on this page at the Moltan site

http://www.moltan.com/Products/absorbentsDE.htm

says:

"When diatomaceous earth is quarried, milled, finely ground, heated, and passed through a screen, it becomes a porous granular product. This is a porous product with microscopic openings, and when magnified, looks like tiny sponges. Clear water can pass through these openings; but particles, as small as one to three microns, are trapped during the first pass through the media."

Which doesn't mean that the products Moltan sells would again break down to the "finely ground" state they were in early in the manufacturing process -- might depend upon the results of that heating -- I believe you observed earlier that the heating for processing this form of DE was dramatically less than that used in manufacture of swimming pool DE. I was considering that the granules might return to the dust state, under garden conditions, and if they didn't, what effect an accumulation of this manufactured granular product might have on the garden.

I think you are misinterpreting "finely ground" as meaning micronized powder like food grade DE. It is finely ground into a granular size and screened to the specifications of the sizes desired. The granules are passed though an oven on a conveyor belt to sterilize it and remove any moisture, that doesn't change its natural state in any way.

Originally Posted by JLJ_

It has been several years since I looked into this -- it was before I began using food grade DE to deal with cabbage worms, etc -- when I wanted to be sure it would not hurt earthworms. My recollection is that in that search I ran across a study of one or more sites that found reduction or absence of particular pests in soil naturally high in DE -- near DE mining areas, as I recall. That doesn't mean that the same would be true of DE blended with the soil of average gardens, as the overall composition of the soil, level of natural moisture, etc. would be expected to play a role -- just suggests that an accumulation of DE in garden soil *might* have an effect, and if so, one would want to try to ensure that it was a beneficial effect. (Beneficial from the point of view of gardening primates )

Your seed starting results have been so impressive I am hoping to incorporate DE into my seed starting combinations -- probably in some layered form. Seems likely that this would result over time in introducing more DE to the garden soil than gets there as a result of my DE plant dusting. Still, I suspect that DE accumulation in the garden would not be a problem -- but I try to think such things through in advance -- hard to get it out, once it's in there, if letting it get into the garden soil turns out to be an "oops".

I think you worry too much.
Once you get to using it you'll find that granular is not the same as the micronized DE you use for insect control. DE is much more structurally stable than Perlite which is pretty easy to crush to dust between your fingers. There will be some dust in the bag, but because of abrasion between the particles that is unavoidable with any natural mined mineral or one altered by man.

[RayR]

Some reading on the effects of DE as a soil ammendment

Effects of diatomite on soil consistency limits and soil compactibility

EFFECT OF DIATOMITE ON GROWTH OF STRAWBERRY

Effects of diatomite on soil physical properties

Sustainable effects of diatomite on the growth criteria and phytochemical
contents of Vicia faba plants

Good info on the AXIS brand of diatomaceous earth and the benefits of DE in soil.

[dipchip2000]

Hi all

Is there a consensus of opinions as to adding the DE to our regular seed starting mediums to maybe improve root structure and maybe not dry out so readily. I am thinking maybe 30 to 40 percent to metro360. I am also thinking maybe 50 percent to the potting up medium. Has anyone tried these experiments yet??

ron

[RayR]

Originally Posted by dipchip2000

Hi all

Is there a consensus of opinions as to adding the DE to our regular seed starting mediums to maybe improve root structure and maybe not dry out so readily. I am thinking maybe 30 to 40 percent to metro360. I am also thinking maybe 50 percent to the potting up medium. Has anyone tried these experiments yet??

ron

Ron, I've been thinking the same thing. Levent already has proven from his experience with DE in subirrigated planters that you can raise very nice plants to full maturity in straight DE or a mix of DE and a standard potting medium. Although I've been amending my conventional containers with DE, I've not gone to anywhere near that high of a percentage.
Since my initial interest is this was to see if I could get faster growing, healthier transplants from this passive hydroponic method and my main interest is organics, I'm going to go further and do some side by side seed starting experiments with straight DE, DE & peat based mix, and DE & coir to see if there are any notable differences.

[dipchip2000]

Ray

I am also going to play with a mixture with different percentages of DE in my seed starting this season. I will not even be starting seeds till January but I am also considering amending one of my 3x12 beds with 2 sacks(15pound) of DE tilled and mixed with the soil.

ron

[Rockporter]

I transplanted my rainbow chard, salad bowl lettuce and romaine lettuce seedlings today. They are very strong and I think they will do well in the garden. I will take some photos tomorrow.

[Levent]

My tomato Red Robin seedling is big enough now to transplant to a 1,8 lt. subirrigation pot.I'll use diatomite as medium.Another one necessary to pot is Tzimbalo (Solanum caripense) seedling.They both are under lights and will stay in grow box till harvest!

[RayR]

That Tzimbalo is a pretty exotic plant I see. The fruit look like tiny melons. Have you grown that before?