Diatomaceous Earth as a seed starting medium

[svalli]

I have now filled all my bottom watering seed starting trays with the moler type DE (sold here for cat litter). Marigolds on right side of the photo started to germinate just in one day. I have flowering tobacco in the middle covered with vermiculite and behind it under the lid are petunia and fuchsia cuttings rooting. Tomatoes on the left side are soon ready for transplanting, but then they take more space under the lights, so I may let them grow one more week in DE.
I started some pepper seeds in normal potting soil before buying the bag of cat litter and fungus gnat larva ate the roots of many of them and they did not come up. I had to sow new Beaver Dam seeds in DE and no gnat problem with them. I just love how easy the DE is for germinating.


Sari

[Labradors2]

I'm considering using DE for growing seedlings. I already bought some fish meal and K-mag. Can I use that as fertilizer?

Linda

[RayR]

Originally Posted by Labradors2

I'm considering using DE for growing seedlings. I already bought some fish meal and K-mag. Can I use that as fertilizer?

Linda

Fish meal is good for containers and soil, it's insoluble organics so it takes time to break down via microbes. A liquid fish hydrolysate or a liquid fish hydrolysate/kelp blend is a better choice for seedlings since it contains all the macros and micros the seedlings will need in more readily available forms.

K-Mag (potassium magnesium sulfate) is very soluble in water but it is only a source of potassium, magnesium and sulfur. It's good in small quantities when those specific nutrients need to be bumped up a notch when called for in a fertilizer program.

[Labradors2]

Thanks very much RayR,

Since I spent my fert allowance on a big bag of fish meal, I guess I'll have to grow my seedlings in potting soil amended with a little DE.

The fish meal is 7-3-3 so I bought the K-Mag (0-0-22) to boost the Potassium.

Linda

Originally Posted by RayR

Fish meal is good for containers and soil, it's insoluble organics so it takes time to break down via microbes. A liquid fish hydrolysate or a liquid fish hydrolysate/kelp blend is a better choice for seedlings since it contains all the macros and micros the seedlings will need in more readily available forms.

K-Mag (potassium magnesium sulfate) is very soluble in water but it is only a source of potassium, magnesium and sulfur. It's good in small quantities when those specific nutrients need to be bumped up a notch when called for in a fertilizer program.

[b54red]

Linda, you can still start your seed in the DE and when they are up give them a mild dose of any good liquid fertilizer. When they start developing some true leaves just pot them up into potting soil. The advantage of starting the seed in the DE is the speed of germination, the high percentage of germination and the very rare occurrence of damping off when using it. I start all of my seed except beans and squash in DE in egg cartons. I then pot them up if they need to be larger before transplanting. Things like lettuce I just leave in the DE.

I am leaving my tomatoes in the DE until I get them grafted and I have fine healthy looking plants in egg carton cells that are as large as 8 inches tall. I really don't know how long I can keep them in those tiny little compartments with only a few tablespoons of DE to support them. I give them weekly doses of the Apples and Oranges fertilizer from Urban Farms and I have been amazed at how healthy they have grown in those conditions. After grafting I pot them up into larger containers with the larger size DE (Optisorb) and once they come out of the healing chambers I will pot many up into regular potting soil but I am going to keep a lot of them in the DE and see how they do in the hardening off process outside.


Ray, I am constantly seeing new threads on the forum about people having problems germinating seeds so I guess most of them still haven't taken the time to read your thread on using DE as a seed starting medium. I cannot believe the contortions some of them are going through in their attempts to get good germination. I used to go through some of those same contortions and thank you again for the information on UltraSorb as a seed starter. It has made my life so much easier.

The biggest problem I have now is my old habit of starting far more seeds than I needed because of past problems with germination and damping off. Now I find myself throwing out and giving away unbelievable amounts of seedlings. The fact that I am throwing away spinach seedlings because I have too many to plant since I started using DE is still a surprise to me. I used to plant huge numbers of spinach seeds just to get a few seedlings most of the time. Now my germination rate is usually far higher than what is indicated on the packages. I guess the seed companies need to start using UltraSorb for their germination tests.

Below is a pic of some of the plants I am using for grafting that was taken a week ago. Those plants are now nearly twice that big and the ones I haven't grafted yet are still in the little egg carton cells. I guess if you kept them to one plant per cell you could easily transplant them into the garden straight from the egg cartons. The only problem would be keeping them from getting too dry when hardening them off. You would definitely have to keep a watering tray under them when it gets hot and windy. I may even try it and let you know how it works but most of the cells actually have more than one plant in them.

Bill

[JamesL]

Bill,
Question - Why the choice of the Apples and Oranges Fert as opposed to the Veggie or Texas Tomato food?

[bestofour]

I haven't read every single post so I hope I'm not asking a stupid question but the only DE I've ever used was to deter crawling bugs. Is this what you're talking about using for seed germination?

[RayR]

Originally Posted by bestofour

I haven't read every single post so I hope I'm not asking a stupid question but the only DE I've ever used was to deter crawling bugs. Is this what you're talking about using for seed germination?

ARGH! No powdered DE of any kind.
Your punishment shall be to read through all six hundred thirty something posts.

[Delerium]

Ray what are your thoughts of using DE in mushroom cultivation as retaining humidity in the growing medium. It's been something I have been wanting to play around. If it wasn't for this thread i probably would have never figured out how easy it is to graft using DE. But now I need something new to keep me going. So what are your thoughts on using granular DE mixed with other substrate mediums to improve air flow within the medium and retaining moisture?

[RayR]

Originally Posted by Delerium

Ray what are your thoughts of using DE in mushroom cultivation as retaining humidity in the growing medium. It's been something I have been wanting to play around. If it wasn't for this thread i probably would have never figured out how easy it is to graft using DE. But now I need something new to keep me going. So what are your thoughts on using granular DE mixed with other substrate mediums to improve air flow within the medium and retaining moisture?

Ummmm....not a clue. Never got into shroomery yet. Do they use any inorganic components in mushroom substrate for that purpose?

[rockyonekc]

Originally Posted by bestofour

I haven't read every single post so I hope I'm not asking a stupid question but the only DE I've ever used was to deter crawling bugs. Is this what you're talking about using for seed germination?

You can read about this in post #1.

[Alpinejs]

Part I....I sympathize with bestofour as I just stumbled upon this thread and, at age 76, I
haven't time enough left to read all the posts, so I will tell you what I did and you all can
tell me how it was wrong. Okay?

I bought a bag of DE at Autozone, soaked it in bucket of water and then filled the 71 cubicles
of a Jiffy Seed Starting tray and left one empty to monitor the water level for "wicking". I put two seeds
in each cubicle about 1/8 inch deep. I watered it well and then
put the tray on a heating pad with the plastic lid on top.

Okay, go for it and tell me what I did wrong only be gentle as I cry easily.

[Alpinejs]

Part II....I have become a convert and fan of nctomatoman's dense planting
system. Does anyone know if this would work with DE?

[RayR]

Originally Posted by Alpinejs

Part I....I sympathize with bestofour as I just stumbled upon this thread and, at age 76, I
haven't time enough left to read all the posts, so I will tell you what I did and you all can
tell me how it was wrong. Okay?

I bought a bag of DE at Autozone, soaked it in bucket of water and then filled the 71 cubicles
of a Jiffy Seed Starting tray and left one empty to monitor the water level for "wicking". I put two seeds
in each cubicle about 1/8 inch deep. I watered it well and then
put the tray on a heating pad with the plastic lid on top.

Okay, go for it and tell me what I did wrong only be gentle as I cry easily.

Sounds like you're doing fine.
You bought Ultrasorb, pure granular DE and not something else like food grade fossil flour for insect control.
There is no need to soak the DE in water ahead of time, some people do as they prefer to screen out the finer dust particles, that's OK but not critical.

Originally Posted by Alpinejs

Part II....I have become a convert and fan of nctomatoman's dense planting
system. Does anyone know if this would work with DE?

No reason I can see that it wouldn't work with the dense planting method.
One important thing though, Craig uses MetroMix 360 on his trays which like most commercial seed starting mixes and light potting soils has a starter fertilizer charge added too it by the manufacturer.
DE has no significant nutrients in it, so fertilization is critical at the true leaf stage. You can pre-charge with a very light dose of complete soluble fertilizer in the beginning or wait for true leaves to emerge. It must be a soluble fertilizer whether organic, synthetic or hybrid.

[peebee]

Originally Posted by Alpinejs

Part II....I have become a convert and fan of nctomatoman's dense planting
system. Does anyone know if this would work with DE?

I did dense planting with Ultrasorb and it worked beautifully! I didn't even bother with fertilizing; I just fertilized a while after I repotted the seedlings in their own little cups/pots.
I didn't moisten the Ultrasorb either, it is hard to handle when wet, I find. I just put a bit of coffee filter in the bottom of my pots, pour or spoon in the Ultrasorb (dry) making sure not to breathe in any dust. I do it outdoors where there is plenty of ventilation. Sow the seeds, cover with some more dry U. and bottom water. It wicks up water so quickly. It changes color from white to beige. I kept it moist later by misting with a spray bottle.
I used to have problems with germination, damping off, etc but this stuff is so easy. I'll never go back to the other stuff again. DE is a NO-BRAINER! Thanks to this thread!