Diatomaceous Earth

Master_Gardener · May 31, 2013

Long ago I bought some Diatomaceous Earth to control pests. I had no idea what I was doing at the time and I bought the DE for swimming pool filters. I understand now that DE comes in two flavors. The one for pools has a higher Si content and is not well suited for pest control. Since Si is a nutrient, will it help or hurt to apply this to my garden?

I understand the cautions about inhaling DE.

Redbaron · May 31, 2013

Filter grade DE won't hurt anything. It isn't as effective at pest control, but it isn't harmful to the soil.

bughunter99 · May 31, 2013

I would skip it entirely. The low grade annoyance is that it is painful in the eyes and in cuts. The low grade danger of inhaling it is that it irritates the lungs. The high grade danger is that it can be associated with lung cancers if inhaled in large amounts. This is probably unlikely to happen in your garden unless you practices are really strange, but why mess with it at all. IMO I don't want stuff in the garden that I have to worry about inhaling. I don't see it as a nutrient being worth it.

Stacy

RayR · June 7, 2013

Filter grade DE is flux calcined at high temperatures which increases the pour space and changes the structure of the DE to crystalline silica. Sand is also crystaline silica but it's not dangerous because the particle sizes are too large to inhale into the lungs. Filter grade DE should not be used for anything other than filtering.

Finely ground DE for insect control is mostly amorphous silica just as it is mined from the earth, which is typically less than 2% crystalline silica. There is only a very small amount of Si in DE that is in water soluble form and that is the only form that is plant available.

Hermitian · January 7, 2014

Quote:

Originally Posted by RayR

Filter grade DE is flux calcined at high temperatures which increases the pour space and changes the structure of the DE to crystalline silica. Sand is also crystaline silica but it's not dangerous because the particle sizes are too large to inhale into the lungs. Filter grade DE should not be used for anything other than filtering.

Finely ground DE for insect control is mostly amorphous silica just as it is mined from the earth, which is typically less than 2% crystalline silica. There is only a very small amount of Si in DE that is in water soluble form and that is the only form that is plant available.

The sale and use of DE for pest control in California is illegal -- and for good reasons. Cesar Chavez was a major proponent of the ban.

Durgan · June 7, 2013

Seed and Feed suppliers have diatomaceous earth which farmers use on their animals. I purchase it from a local seed and feed, and keep it in a closed five gallon pail.

I find it to be completely useless for discouraging insects in my garden. All the information as to its effectiveness is anecdotal. There are few if any meaningful clinical trials.

RayR · June 7, 2013

Quote:

Originally Posted by Durgan

Seed and Feed suppliers have diatomaceous earth which farmers use on their animals. I purchase it from a local seed and feed, and keep it in a closed five gallon pail.

I find it to be completely useless for discouraging insects in my garden. All the information as to its effectiveness is anecdotal. There are few if any meaningful clinical trials.

I've had the opposite experience with insects, although DE can kill soft bodied insects, it's been great for me at discouraging cucumber beetles and Japanese beetles from feeding on leaves.

Rockporter · June 8, 2013

Quote:

Originally Posted by RayR

I've had the opposite experience with insects, although DE can kill soft bodied insects, it's been great for me at discouraging cucumber beetles and Japanese beetles from feeding on leaves.

Myself as well, I have also found that I can keep the ants out of my pots if I spread it around them and onto the plant as well. I also used it on the first two inches of my squash plants stem and have not had the problem of squash bugs eating and laying babies. I would say even if there are no clinical trials to prove or disprove I will continue using food grade DE in my garden.

Tracydr · March 24, 2014

Quote:

Originally Posted by RayR

I've had the opposite experience with insects, although DE can kill soft bodied insects, it's been great for me at discouraging cucumber beetles and Japanese beetles from feeding on leaves.

I found DE to be very effective at killing little baby squash bugs. Not SVB but the bugs that look like stink bugs. It's all I use. I see one of those buggers and I dust the squash until its white.
The hard part is that the underside of the leaves also have to be dusted. I always dust around the bottom of the plant well,too.

reeltime · June 10, 2013

I use fg de sometimes but it doesn't work on Leaffooted bugs

the old grab and smash is the only thing that works for them.

Sent from my SGH-T989 using Tapatalk 2

RayR · June 10, 2013

Leaffooted bugs I've never seen, but for beetles if there is a even coating of DE across the leaf surface, they won't feed. It's more of a physical barrier thing, it works similar to the kaolin clay product Surround WP
DE doesn't hold up as well as Surround WP does after rain, so it needs to be reapplied.

timeless · December 30, 2013

I might get really razzed here, but I find DE to be completely worthless if pest control is your goal.
It's not all it's cracked up to be, you have to re-apply after every watering or rain.
It might work a little on aphids, but not much.
The good news is, it won't do any harm to your soil.

Durgan · December 30, 2013

Quote:

Originally Posted by timeless

I might get really razzed here, but I find DE to be completely worthless if pest control is your goal.
It's not all it's cracked up to be, you have to re-apply after every watering or rain.
It might work a little on aphids, but not much.
The good news is, it won't do any harm to your soil.

I use it but never feel as if it accomplishes anything. I wont buy another bag.

Redbaron · January 6, 2014

I have good luck with DE for certain things. But it is all in how you use it. A good example is aphids. I get pretty good aphid control with DE, but NOT by dusting the plants. I dust the anthills and make barriers at the base of the plants aphids like to attack. The ants then can't protect and farm the aphids, and then the aphid predators eat them all up.

If you just dust the plant leaves, you'll likely as not kill as many or more predators as aphids and neither 100%. But it always seems predators get affected more than the pests. I think this is because predators are more active scouring the plants in search of pests to eat. While a pest once he finds a plant to munch on, usually stays put and gets to munching. So since DE requires an insect to walk through it to have any effect, it tends to kill at least as many, if not more, predators as pests. So actually in this respect is no better than a chemical pesticide and less effective.

Used creatively though? I love DE.

Sun City Linda · January 7, 2014

I purchased a bag of DE in the garden section of a national retailer last year. What else would it be used for in gardening if not pest control?

May 31, 2013	#1
Master_Gardener Tomatovillian™ Join Date: May 2013 Location: Central Indiana 6a/41 Posts: 131	Diatomaceous Earth Long ago I bought some Diatomaceous Earth to control pests. I had no idea what I was doing at the time and I bought the DE for swimming pool filters. I understand now that DE comes in two flavors. The one for pools has a higher Si content and is not well suited for pest control. Since Si is a nutrient, will it help or hurt to apply this to my garden? I understand the cautions about inhaling DE. __________________ Russel USDA: Zone 6a, Sunset Zone 41 - 15 miles NW of Indianapolis, IN I had a problem with slugs. I tried using beer but it didn't work, until I gave it to the slugs.

May 31, 2013	#2
Redbaron Tomatovillian™ Join Date: Sep 2012 Location: Oklahoma Posts: 4,488	Filter grade DE won't hurt anything. It isn't as effective at pest control, but it isn't harmful to the soil. __________________ Scott AKA The Redbaron "Permaculture is a philosophy of working with, rather than against nature; of protracted & thoughtful observation rather than protracted & thoughtless labour; & of looking at plants & animals in all their functions, rather than treating any area as a single-product system." Bill Mollison co-founder of permaculture

May 31, 2013	#3
bughunter99 Tomatovillian™ Join Date: Feb 2010 Location: zone 5 Posts: 821	I would skip it entirely. The low grade annoyance is that it is painful in the eyes and in cuts. The low grade danger of inhaling it is that it irritates the lungs. The high grade danger is that it can be associated with lung cancers if inhaled in large amounts. This is probably unlikely to happen in your garden unless you practices are really strange, but why mess with it at all. IMO I don't want stuff in the garden that I have to worry about inhaling. I don't see it as a nutrient being worth it. Stacy Last edited by bughunter99; May 31, 2013 at 04:42 PM.

January 6, 2014	#14
Redbaron Tomatovillian™ Join Date: Sep 2012 Location: Oklahoma Posts: 4,488	I have good luck with DE for certain things. But it is all in how you use it. A good example is aphids. I get pretty good aphid control with DE, but NOT by dusting the plants. I dust the anthills and make barriers at the base of the plants aphids like to attack. The ants then can't protect and farm the aphids, and then the aphid predators eat them all up. If you just dust the plant leaves, you'll likely as not kill as many or more predators as aphids and neither 100%. But it always seems predators get affected more than the pests. I think this is because predators are more active scouring the plants in search of pests to eat. While a pest once he finds a plant to munch on, usually stays put and gets to munching. So since DE requires an insect to walk through it to have any effect, it tends to kill at least as many, if not more, predators as pests. So actually in this respect is no better than a chemical pesticide and less effective. Used creatively though? I love DE. __________________ Scott AKA The Redbaron "Permaculture is a philosophy of working with, rather than against nature; of protracted & thoughtful observation rather than protracted & thoughtless labour; & of looking at plants & animals in all their functions, rather than treating any area as a single-product system." Bill Mollison co-founder of permaculture

June 7, 2013	#4
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,466	Filter grade DE is flux calcined at high temperatures which increases the pour space and changes the structure of the DE to crystalline silica. Sand is also crystaline silica but it's not dangerous because the particle sizes are too large to inhale into the lungs. Filter grade DE should not be used for anything other than filtering. Finely ground DE for insect control is mostly amorphous silica just as it is mined from the earth, which is typically less than 2% crystalline silica. There is only a very small amount of Si in DE that is in water soluble form and that is the only form that is plant available.

June 7, 2013	#6
Durgan Tomatovillian™ Join Date: Feb 2013 Location: Brantford, ON, Canada Posts: 1,341	Seed and Feed suppliers have diatomaceous earth which farmers use on their animals. I purchase it from a local seed and feed, and keep it in a closed five gallon pail. I find it to be completely useless for discouraging insects in my garden. All the information as to its effectiveness is anecdotal. There are few if any meaningful clinical trials.

June 10, 2013	#10
reeltime Tomatovillian™ Join Date: Jun 2013 Location: sunny San leon Posts: 6	I use fg de sometimes but it doesn't work on Leaffooted bugs the old grab and smash is the only thing that works for them. Sent from my SGH-T989 using Tapatalk 2

December 30, 2013	#12
timeless Tomatovillian™ Join Date: Aug 2011 Location: Wilber, Nebraska Posts: 14	I might get really razzed here, but I find DE to be completely worthless if pest control is your goal. It's not all it's cracked up to be, you have to re-apply after every watering or rain. It might work a little on aphids, but not much. The good news is, it won't do any harm to your soil.

January 7, 2014	#15
Sun City Linda Tomatovillian™ Join Date: Mar 2011 Location: SoCal Inland Posts: 2,705	I purchased a bag of DE in the garden section of a national retailer last year. What else would it be used for in gardening if not pest control?