Diatomaceous Earth as a seed starting medium

[claherron]

I have a brandywine seedling up already, ONE day! So far so good. No heat mat either.


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[Nattybo!]

Ok, I am ready to try this! I have read this entire thread. Since I am snowed in and just happen to have some Ultrasorb in the garage I have to try this. I also have some leftover liquid MG-like fertilizer. So I think I'm all set. (Most of my seeds are old and have been spotty at germination, so I hope this DE method works). The results/pictures others have been posting of root growth have been amazing! TY TVille! I never would have thought of this on my own.

[SteveS]

Well this is the second time I have read completely thru this thread.
And I have begun implementing some of the materials & methods described.
I have Ultrasorb, NAPA Floor-Dry & Multi-Purpose Safety Absorbent.
The MPSA is from Moltan but I looked it up & it is Montmorillonite clay.
It has a diagram of a plant on the front so they must think it is suitable for plants, but I figure that it might not be optimum for seed-starting.

Anyhow, let me come to my question. Is it possible to have too much water with the DE?
I have always started seeds in Gardeners Supply APS (Accelerated Propaagation System) which have a water reservoir & capillary matting to wick the water.
I tried starting mater seed in the NAPA floor-Dry first (because I had gotten it first) but germination was quite slow...I have 10 seedlings up out of 36 seeds now after 12 days.
And yes, they are on a heat mat.
I have had somewhat better results with Ultrasorb in a APS with 3 seedlings up out of 24 seeds after 5 days.
Has anyone had this experience?

This AM I started some mater seed in egg cartons with Ultrasorb. Each cell has a little coir at the bottom to prevent the fine DE from exiting the holes. So I will see how that works for me.

Ray, following your lead, I have concocted my own mix consisting of
1 part Pro-Mix BX
1 part Coir
1 part Ultrasorb
1/2 part Worm castings

I haven't tried starting anything in it.
I have just used it to transplant some of my seedlings that I have been using to practice my grafting.

Anyhow I'd just like to thank everybody for all the great ideas using DE for seed-starting. I believe it is truly revolutionary to avoid damping-off problems!

[b54red]

Steve it is possible to have too much water with DE. The only time I have had any significant damping off with seedlings in DE was when the containers with the seedlings were left in a watering tray for an extended period. I know it is more trouble to keep checking on the DE for dryness and watering when necessary but it is far better than dealing with damping off.

On another point. You shouldn't have to put anything in the bottom of the egg carton cells to stop the DE from leaking out if you make the holes small enough. I use a small wooden skewer and put 4 to 6 holes in each cell and have no problem with the DE leaking out. I use the UltraSorb for seed starting.

Bill

[SteveS]

Great!
Thank you, Bill

[RayR]

Steve, the Montmorillonite Clay products by Moltan is mined in Tennesee and is quite acidic. I explained that back in post #26.

Is the NAPA Floor-Dry you have made by Moltan or EP Minerals? I tried the EP Minerals version last year but the PH was lower (PH 6.0 I believe) than the Moltan DE product. If you have the EP Minerals version than that might account for the slower germination.
EP Minerals purchased Moltan last year and are now under the same ownership but their Diatomite mines are in different locations. The Moltan DE just hit the sweet spot for seed starting veggies as far as PH goes (PH 6.8) without any PH adjustments needed.

Just keep in mind the PH is critical to good seed starting for most of the veggies we grow. Commercial seed starting mixes are balanced out to a target PH of 6.5-7.0 for that reason.
Let us know how that mix works out, it should be fine, but investing in a good PH meter or some good PH test strips is a good idea when concocting mixes just to be sure all is good.
The Pro-Mix is fine since it is PH balanced, the UltraSorb will be fine, the Worm Castings should be fine since they are usually at around a neutral PH. Coir is naturally acidic depending where it comes from and what purpose it is intended for, but if you are using a horticultural coir that has been PH balanced to the 6.5-7.0 range then that should be fine also without testing.

[SteveS]

Ray, my NAPA Floor-Dry is made by EP Minerals, so that may explain that.
I think it may be amending my garden beds, along with the Montmorillonite clay!

With all the talk of pH, I have a pH meter purchased & on it's way, should have it next week.
I'll have to test my mix!
I just bottom-watered my egg cartons.
Thank you so much.

[svalli]

I am still trying to locate source for DE here in Finland, but with no luck. We have that cat litter which is made from Danish moler, but it has some fragrance in it. I used it last year with good results, but washing the fragrance off takes time and lot of water.

Today I found the Canadian EcoTraction for 50% off in a store. It is clinoptilolite zeolite and I found RayR's excellent posts from last year about it having too high cation exchange properties to be used as raw. I found that in pre-charged form it has been tested by NASA for soil less growing media. My question then is that how do I pre-charge it? Do I just let it sit in water with lots of liquid fertilizer and then rinse it to get rid of excess?

Sari

[RayR]

Sari, that's pretty much what pre-charge is, soaking the Zeolite in a nutrient solution to saturate the exchange sites. I guess the trick is finding what concentration of nutrients is optimal to avoid nutrient competition between the the Zeolite with its very high CEC and the plant roots. Probably even more a concern with synthetic fertilizers since there is always the danger of over fertilizing and causing root damage. DE is easier since its CEC is very comparable to good soil, so normal fertilizer concentrations for soil seem to work just as well with DE.
In this 2005 Texas A&M experiment for NASA, they used a 50/50 mix of iron oxide coated clinoptilolite zeolite and compost for seed starting and then transplanted the seedlings into their experimental mediums for grow out.

[svalli]

Thanks Ray! I will use the cat litter again for starting my tomatoes, but I may do some experimenting with the zeolite. I'll post what happens with my experiment.

Sari

[ohiofem]

I just finished this very interesting thread. I have NAPA floor dry 8822, purchased last year, which I'd like to use possibly mixed with something else, like Promix. But your comments about it possibly having too low a pH concern me. How do you test the pH of your mix?

[RayR]

Originally Posted by ohiofem

I just finished this very interesting thread. I have NAPA floor dry 8822, purchased last year, which I'd like to use possibly mixed with something else, like Promix. But your comments about it possibly having too low a pH concern me. How do you test the pH of your mix?

I use an digital PH meter I've had for a few years now. A cheaper alternative is PH test papers. I ordered a roll of Hydrion #95 (PH 5.0-9.0) last week, the short range is perfect for soil testing. The 15' roll was only $8.45 delivered from an eBay seller.
I wanted a quick way to test when I didn't want to take out the digital meter. Digital meters are very sensitive and more precise but need to be calibrated on the day you use it, which is fine if you are doing a bunch of tests.

[claherron]

Ray what type of meter do you use? I looked around and the ones that were affordable my gut tells me not to trust the reading. I will have blueberries this year.


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[RayR]

Originally Posted by claherron

Ray what type of meter do you use? I looked around and the ones that were affordable my gut tells me not to trust the reading. I will have blueberries this year.

I have a Milwaukee MW102

[madddawg]

Ray, I have read a lot of the post on here, and find your experiment interesting. I will definitely try this next year. I have everything planted for this year, I think. I may get a wild hair and plant a few more.