Diatomaceous Earth Organic Seed Starting Mix Experiments

[RayR]

I'm kickin oiff this thread for those who like to experiment with new ideas for growing mediums. Last season I continued working with granular Diatomaceous Earth by mixing it with coir and even worm castings to maybe capture the best of both inorganic and organic worlds and see what happens. Well the results were very encouraging with tomato seedlings so I just had to do again and even try some other inputs like some rich commercial bagged composts. More on that later when I get to tomatoes, peppers and eggplant.

First up is lettuce. For that I started with a straight 50/50 mix of granular DE and General Hydroponics Coco Coir back in the second week of March. Doped the medium in 1.5" cells with some organic nutrients and some microherd inoculant (Some Great White and some AZOS that I had left over from last season) and got those lettuce seeds off to a start. The plan was to grow the transplants indoors under T8 lights until I could get them transplanted in containers outside sometime in late April so I could harvest some really big heads of juicy lettuce in early to mid May. Could have got them big and an earlier harvest, but I knew with the very cold spring we had it wasn't going to happen. Lettuce like cool temps, but not that cold.
They grew pretty well indoors in those little cells so I potted some up in 4" pots and continued growing them under the lights until the temperatures outside were warm enough and the container soil unfrozen.

The first picture is the 5 Rouge Grenobloise plants that I grew in those 4" pots on the day that I transplanted them outside on April 19th.

The second picture is one removed from the pot so you can see the root ball. The coir and DE are a great combination. It stays nice and loose allowing for oxygen to get to the roots. And for bottom watering it wicks just as well as DE alone.

The third picture is a close-up of a section of those fuzzy roots and the mix.

[rags57078]

Thanks for all the great info

[MissS]

Ray, have you tried this with multiple seedlings in a pot? If so, how easy were they to separate? The reason I use DE is the ease that I have separating seedlings. I just shake off the DE and there seems to be no root damage when I transplant.

[RayR]

Originally Posted by MissS

Ray, have you tried this with multiple seedlings in a pot? If so, how easy were they to separate? The reason I use DE is the ease that I have separating seedlings. I just shake off the DE and there seems to be no root damage when I transplant.

Yes I did and it was just as easy as with straight DE. Letting the medium get a little dry made it much easier to separate the seedling with little to no root damage which I found was the same using just DE. You probably already know that.
That' s one of the reasons I like coir as part of the mix, it doesn't have the tendency to stick and compact like fine peat moss does. Maybe a coarse grade of peat moss might work the same as coir, haven't tried that.

[MissS]

Thanks Ray. I just might try this.

[MissS]

I tried this mixing with Jiffy Seed Starter Mix.
I had a small disaster using some organic fertilizer which grew mold and killed my plants, so I re-seeded. I had some seed in straight DE and some with Jiffy mix. The seedlings in the mix grew far faster than those in the straight DE.
I have re-potted most of the plants. They separated just beautifully. Today I added some worm castings to those plants that are still too small to move. Hopefully the will make some quick progress.
I will say that I also did some direct seeding into the ground. Those plants are so much further ahead of anything that I have in a pot. Perhaps direct seeding is a better way to go if you are starting plants late.

Patti

[RayR]

What organic fertilizer did you use? I don't understand the relationship between the mold and killing your plants, parasitic molds (damping off) that kill plants aren't interested in dead organic matter, they want the living host.

The thing with lettuce is timing, if it's too cold they grow very slowly, if it's too warm they stop growing and want to bolt to seed. It depends on varieties too since some are slow to bolt in the heat and some not.
Since I grow out some varieties for seed, I have a bunch of volunteers that pop up all over the place in the spring, I don't direct seed myself. Some do OK, but none really do as well as my indoor grown transplants that were started in late winter and planted in containers when the weather is just right outside. That's the way I get huge heads of lettuce. Starting late is very difficult since they have less time to really get growing before the heat drives them to bolt.

[Dutch]

Patti, RayR’s granular Diatomaceous Earth seed starting method has worked so well for me this year, that I have the following extras plants that you can pick up from me and grow this season;

Big Beef, Golden Jubilee, and Lemon Boy - Paseseed
Burpee Brandy Boy, Steakhouse, and Orange Slice - Burpee
Texwine and Pink Elgin - Travis
Nile River Egyptian – BrokenBar
Lescana Beefsteak (Romanian) - Casey
Joe’s Pink Oxheart – Lazy Ox Farm
Ruslan (Orange Beefsteak) and Hihant Lymonyy (Giant Lemon) – Nikitovka Seed
Cherokee Chocolate, Neves Azorean, Anna Russian and Limmony – TGS
Blondkopfchen, Nyagous, and Dester – SSE
Lo Fischer Yellow and Pink Flamingo –Plants grown from my saved seeds (Carolyn’s 2013)

I will PM you my address so you can pick them up this weekend.
Dutch

[MissS]

Sorry for the delay in answering. Somehow I missed the reply in my personal mailbox.

Ray, I used a diluted Neptune's Harvest Fish & Seaweed. Mold grows almost on anything in my house. Including just plain damp soil and my windowsills. I don't see it as a problem with the product, but rather it is my environment. My landlord does not have any vents in the attic. When the windows are closed, mold is a BIG problem. I even use Captan when I am starting seeds. The top of the cells was covered in white/gray fuzzy mold.

For the past two years I have been using DE with fantastic results. The difference in those two years and this years attempt was that before I was using a water soluble product.

Dutch, Thank you for the offer. I will be glad to be meeting a fellow T'villian!

Patti

[RayR]

I can see the problem you have there with the mold spores in the environment. I get some too with organic nutrients, but I've learned to control it. Fish based nutes are a feast for mold, they love the stuff as a food source, it’s near perfect fungi food.
The thing that you have to constantly have to keep in mind with organics is that it is a vast biological chemical factory under your management and not Scotts Miracle Grow or whoever making a limited number of chemicals for you. Neptune's Harvest Fish & Seaweed like any other liquid organic fertilizer, it has some readily available nutrients in it for the plant to take up, but has a lot more that requires microbial activity to release the full benefits for the plant. DE is like any other sterile medium, it’s pretty much a blank slate, no bacteria, fungi or any higher organisms that would make up a Soil Food Web except what might land in it from the air or water. If the mold spores are the predominant organisms in that environment with no antagonists or competition they have a field day.
So the trick is for the manager (you) to give them those antagonists and competitors to keep them molds their place. For that you need biological inoculants, they are cheap and effective and will add a whole host of benefits to the system.
Worm castings are a great addition, lots of good bacteria in there among other things that promote plant growth.
Trichoderma fungi are really good at controlling mold since they are highly competitive mycoparisites that produce antibiotics that kill other fungi, both common molds and they protect the roots from pathogenic fungi that cause damping off. They are also good at making more nutrients available to the plant.
Actinovate is also good which is Streptomyces Lydicus wyec 108, an Actinobacteria that produces fungi killing antibiotics.
For my DE/Organic mix this year I tried something different, instead of the 50%DE/40%Coir/10% worm castings which worked excellent last year, I tried 50%DE/40%Coir/10%Compost. For the compost I tried bagged composts, both Dr. Earth Compost and Coast of Maine Bumper Crop. Both by the way have worm castings as one ingredient. Even though they are both biologically active products, I also inoculated with Humboldt Nutrients Myco Madness for additional beneficial bacteria, tricoderma and mycorrhizae. For fertilizer I used tried Humboldt Nutrients Grow Natural which is an ocean fish and seaweed based liquid fertilizer with other organic components added.
From the picture of the pepper tray you can see a few small spots of white mold on the left side, not much. In the picture of the tomato seedlings, I didn’t have any mold crop up. For the tomatoes I used only the Bumper Crop compost, for the peppers in the picture I used the Dr. Earth compost. Maybe the Bumper Crop added better mold suppression, I don’t know for sure. I didn't use any Actinovate for this run.

[MissS]

Ray thank you so much for the advise and explanations. I have much to learn and try.

I figured out that I needed to add some competitive bacteria/spores to control the mold. I already have purchased some MycoGrow and Worm Castings to try to control the mold spores. Do you think that that will work for this? I have not tried it yet. I would also like to try it on the plants that I bring in to over-winter, rather than using the Captan all of the time. Using fungi and bacteria just seems to be a healthier alternative to me.

My hydroponics store does have Actinovate. Would that be a better choice for this situation than the MycoGrow? I do not recall seeing the Humbolt products at the store. I will have to check for them the next time I visit. It may be worth a try using next season.

I met Dutch yesterday and what a great guy he is! He has a fantastic set-up and the most beautiful plants. His garden is so neat and orderly. His pictures do not do his greenhouse justice. He gave me some plants that are amazing.

Thank you Dutch! You are truley a kind and generous man.

Patti

[RayR]

MycoGrow and Worm Castings will be fine. You can try Actinovate in combination with any other biological inoculants and see what works best in your situation. Surface molds have not been a big issue for me as they are for you so I can't say what will work better in your environment. Got to experiment.
I would get away from using Captan fungicide when going the biological approach. Captan is a mixed bag when it comes to its effect on beneficial microorganisms. It will inhibit some Trichoderma fungi strains but some other Trichoderma strains are able to develop a strong tolerance to it within hours. For bacteria, it will inhibit some species, but others it will have no effect and some others are able to break Captan down and mine it as a food source.
For Mycorrhizae, Captan is bad news.

Glad you hooked up with Dutch and lightened his load of tomato transplant abundance.
I gave away about 60 extra plants this week myself.

[RayR]

I changed the mix a little this year for the Tomatoes. 50%DE/30% CocoTek Coir/10% Coast of Maine Bumper Crop Compost/10% Worm Power Worm Castings. Fertilized with General Organics Nutrients again this year, and inoculated with Humboldt Nutrients Myco Madness
All grew healthy and happy.

[JamesL]

Great looking plants Ray!
At what point are you going to pot up? Are they going in the ground or pots?

[RayR]

Originally Posted by JamesL

Great looking plants Ray!
At what point are you going to pot up? Are they going in the ground or pots?

Ya, it's a jungle in there and I'm late potting up, but that's typical for me. Got most of the pepper plants potted up, going to start tomorrow on tomatoes and ground cherries. Still got 3 weeks or so till planting out. Most of the tomatoes will go in ground, some in containers. I'll have a lot of extras as usual to give away.
A client of mine called me today who owns a restaurant, he saved me 10 5gal buckets. Do I dare add anymore plants to my yard?