Diatomaceous Earth as a seed starting medium

[Greatgardens]

I've tried DE with fairly fine particle size from an auto parts store. (Think sizing similar to coarse sand.) Does OK, but I have one issue with it. Keeping it damp, the particles seem to "weld" themselves to each other after awhile. I don't get any better results than with Burpee's (coir) seed starting mix that is topped with about a 1/4" of vermiculite. Has anyone else noticed the DE particles sticking to each other?

[T0mat0stevek]

Has anyone started leeks in DE? If yes, what were your results?
Thanks, Steve

[RayR]

Originally Posted by T0mat0stevek

Has anyone started leeks in DE? If yes, what were your results?
Thanks, Steve

I've started onions and leeks in DE, it worked well.
The only seeds that may not perform as well are those that don't tolerate the naturally higher PH of the DE as well as the seedlings grows, but I haven't run into any that won't germinate in DE.
At the least I pre-sprout all larger seeds or those that can at least be handled by hand or tweezers (Tomato, Pepper, Eggplant, Lettuce, Brassicas etc..) on a bed of moist DE, much like you would use the paper towel method.

In the last number of years, I've learned to create my own seed starting mix of primarily the large granule Optisorb DE with Coco Coir and Worm Castings. That involves acidifying the DE with regular white vinegar, flushing it thoroughly with fresh water, then combining it with the organic ingredients and letting it sit and cook for a few days to stabilize the PH to around 6.50 more or less. Having a good PH meter is important for this so you can check the results. All my tomato seedlings will be raised this way until the potting up stage. I've already got lettuce and endive transplants ready to transplant now grown in the mix.

[T0mat0stevek]

This year I started my leeks, onions, and tomatoes in 100% DE with great success.