Diatomaceous Earth as a seed starting medium

[creister]

My seeds have been planted for a week, and none have sprouted yet. Tomato seeds that is. Is that seem normal for starting in DE? When I used peat, it was always at least a week.

[Father'sDaughter]

Originally Posted by creister

My seeds have been planted for a week, and none have sprouted yet. Tomato seeds that is. Is that seem normal for starting in DE? When I used peat, it was always at least a week.

Mine are typically up in less than a week with DE. If you know your seeds are good, then it may be a problem with temperature or watering--too much or too little.

[creister]

I keep the house at 70, so not sure if that slows down the germination?

[Father'sDaughter]

They should be fine at 70. Are you keeping the DE consistently moist, but not soggy to the point where the seeds might rot?

[creister]

I don't think I've given them too much water, just use the color of the de as an indicator as well as feeling the top. I put the seed trays under a heating pad to see if that would help. I don't let the de completely dry out.

[Father'sDaughter]

Maybe someone else has some suggestions, but it sounds like you're on target with temp and watering. If I have no-shows, I try to give them at least two to three weeks before I start carefully poking around in the DE to see what the seeds are doing. Sometimes I find they've started sprouting and chalk it up to slow germination, and sometimes I find that they've done absolutely nothing and I know it's time to re-sow.

[RayR]

Originally Posted by creister

I don't think I've given them too much water, just use the color of the de as an indicator as well as feeling the top. I put the seed trays under a heating pad to see if that would help. I don't let the de completely dry out.

Do you have a cover over your tray, humidity dome or such to keep in the moisture? How deep did you plant the seed? 1/8" is best.
If you think you did everything right and still no germination, then I would do a germination test so you can see if the seed is viable. Use the paper towel/coffee filter method or the DE method that I use to pre-sprout seed.

[creister]

Good news as some are starting to push up. I don't think I was giving them enough water. Ray, do you leave your trays in a watering tray continuously? Or do you bottom water and take seed containers out of the water every time? I also have turned on the oven light and leave the trays in there as well. It seems to help.

Can I over water by leaving my trays in water continuously?

[BigVanVader]

Yes over watering can cause the seed to rot. My personal method requires only 1 (top) watering. I just water till it comes out of the bottom then let it drain a minute or 2. I also like to use clear salad mix containers so i can see that the DE is wet all the way through. Then just place any decent humidity dome/cover/lid over them, sit it on the heat mat, and it should retain the moisture until germination. Light isn't required for most seeds.

[RayR]

Originally Posted by creister

Good news as some are starting to push up. I don't think I was giving them enough water. Ray, do you leave your trays in a watering tray continuously? Or do you bottom water and take seed containers out of the water every time? I also have turned on the oven light and leave the trays in there as well. It seems to help.

Can I over water by leaving my trays in water continuously?

If the trays are on the heat mat and humidity dome is on I don't leave any extra water in the tray, but when the seeds are up and the dome is off I will leave some water, 1/2" or less in the tray, the DE will wick up to fill in what water has evaporated. You can't overwater the DE that way, it will absorb what water it can hold and there will be plenty of air space between the aggregates.

Seedling01a.jpg Seedling02a.jpg

(Sorry about the images - both pictures are the same size flats. I guess I was a bit closer to the second one when I shot the picture...opps!
Also, I was trying to get these pictures to show up a thumbnails...obviously didn't work!

Each nine-pack flat was planted with the same tomatoes. The white plant markers marks the orientation. Obviously, the flat on the left is potting soil (PS), the one right is Diatomaceous Earth (DE).

Both flats were started, covered with plastic wrap, on a heating mat. Strange, some of seeds did equally well both in PS and DE, while others are still lagging quite a bit behind in the DE. The first sprouts showed up 3 days after sowing (1/20/15). As soon as the seeds sprouted, they were uncovered, and bottom watered. Since there is no nutriments in the DE, as soon as leaves appeared, they were regularly water with a dilute MG-AP aka 'Bluestuff'. So I guess for me, the jury is still out on the DE. I think I'll start playing around with the hybrid approach...various ratios of PS and DE.

Anyway, cute little babies, dontcha' think...

Mike-

[RayR]

Originally Posted by MikeBiondo

Attachment 46953 Attachment 46954

(Sorry about the images - both pictures are the same size flats. I guess I was a bit closer to the second one when I shot the picture...opps!
Also, I was trying to get these pictures to show up a thumbnails...obviously didn't work!

Each nine-pack flat was planted with the same tomatoes. The white plant markers marks the orientation. Obviously, the flat on the left is potting soil (PS), the one right is Diatomaceous Earth (DE).

Both flats were started, covered with plastic wrap, on a heating mat. Strange, some of seeds did equally well both in PS and DE, while others are still lagging quite a bit behind in the DE. The first sprouts showed up 3 days after sowing (1/20/15). As soon as the seeds sprouted, they were uncovered, and bottom watered. Since there is no nutriments in the DE, as soon as leaves appeared, they were regularly water with a dilute MG-AP aka 'Bluestuff'. So I guess for me, the jury is still out on the DE. I think I'll start playing around with the hybrid approach...various ratios of PS and DE.

Anyway, cute little babies, dontcha' think...

Mike-

Mike, that's a mystery you are going to have to solve, I've never had that kind of thing happen in straight DE or a DE mix.
The small stunted seedlings look really pale in the picture, like they are not getting enough nutrients. Are you bottom watering/feeding the DE tray and let it wick up? That's the only way you can tell that the DE is saturated all the way through in all the cells.

Yeah Ray, it is a bit of a mystery. The color in the photos is a bit washed out - the seedlings don't look quite that bad. The real mystery to me is that the seedlings in the DE that look small/stunted are actually newly germinated. Yep, they just popped out a few days ago. I'm not sure if I put them a bit deeper that I should have, or what. I'll have to watch that closer.

Thinking I did put the seed too deep in the DE, I did another flat where I filled the cells with DE (Ultrasorb btw), then just laid the seeds on top, and then sprinkled a very thin layer of DE - just enough to cover the seed. Then bottom wateded . The strange thing about that is they became *extremely* leggy. Exactly the same setup as previous attempts. The only difference was an extremely shallow seed depth. Interesting!

Yes, all watering is bottom watered, with occasional misting to loosen 'helmets'.

Regardless of the results, it's fun experimentin'...

Mike-

[RayR]

The newly germinated seeds were planted at the same time as the large seedlings?
I don't plant seeds deeply myself, about 1/8" down. That wouldn't cause leggy seedlings, low light is the only thing that causes leggy seedlings.

[svalli]

I wrote earlier about the expanded silicate gravel, which is sold here for sanding icy pavements. About a month ago I sowed some hot peppers seeds into it and put some fuchsia cuttings to root into it. The peppers are growing nicely and the fuchsias rooted and started growing. I have yet not moved those from the gravel, since the growth has been so good. I keep a bit water on the bottom tray all the time and have added some soluble fertilizer to the water.

On Sunday I sowed 75 tomato seeds into that same stuff. I placed the tray on top of my DIY-LED-light, which get about 104°F on the top. Yesterday I noticed that first tomatoes have sprouted, so I had to move it off from top of the light fixture and set it under a similar light. Today I found out that 55 of the seeds have already sprouted. Even seeds, which I have bought 2006 and 2007 are coming up and germination for those old seeds is already 80%. What ever this stuff is, it seems to wick well and has caused really rapid germination.

This stuff looks just like the DE, but some of the granules float. Floating does not really cause any problems, unless I put too much water on the tray, but that wold also drown the plants.

Sari