Hi
@Pieyeguy420. No worries about the earlier posts - coming from other forums, your experience likely made your comment about negative responses understandable. You will find that this forum is different. Flaming doesn't happen, and when attitude seems to be moving in that direction, very rare here, it gets dealt with. On the whole, this is one of the most helpful, knowledgeable, and friendly forums that I have participated on.
Re. the black dirt, all I can tell you is that I hit mine heavily with Bacillus thuringiensis israelensis, which should have nuked any live or emerging larvae in my soil. I knew the buggers were in there, at least their eggs were, but figured that the Bti would prevent them from surviving and making adults. I also put leaf mulch on top of the soil, and liberally dusted it with diatomaceous earth which I figured should knock out any emerging adults or any that showed up from elsewhere. In spite of my treatments, the larvae survived and snacked on my seedling roots, and dozens of adults emerged from at least one of my 10 gallon fabric pots. Shortly before I shut the grow down, I was killing between 12 and 20 of the buggers each day, and the sticky traps (3 5X6 inch jobs) picked up more or less that many as well. All told, I germinated four seeds in the soil, one turned into an obvious runt, one showed enough life that it might have survived to make another runt, and I expect the other two were unlikely to survive at all. I suppose I could have tried again, but my grow time this winter is limited, so I gave up and am now re-starting in Sunshine #4. I was also tired of killing seeds and fighting gnats.
As to controlling larvae with nematodes, I know next to nothing about it, so I am not the person to ask. I can certainly tell you that controlling them with the tools I used may not work well enough to keep seedlings happy. It is the larvae that do the damage, and it is the really young plants that they really bugger up. The little bastards seem to actively seek out emerging seedlings. I dug up one emerging seed due to another unrelated screwup, and there were something like 8-10 of the larvae actually crowded right at the new root, and I could fine none elsewhere. This was after the seedling had been in the soil for only about 8 hours. It seemed that every larva in the pot had gathered to chow down on the only weed seedling in the pot, and they did it very quickly.
If I were you, I would consider doing the same treatment I did with Bti and diatomaceous earth, it is possible that I just got unlucky, or maybe I did the Bti treatment wrong. I grated the mosquito dunk into fine powder and mixed it throughout the soil. It seemed to have done the job in one out of three pots, but the other two had larvae, and one of the three seemed to be the source of most or all of the adults I was killing.
One further suggestion is to germinate your plants in solo cups or the like filled with sterilized starter soil. I would not germinate in the outdoor soil if I were you. If you can get the babes well established before planting in your black dirt, they will have a better chance of dealing with challenges in there.
Anyway good luck with your grow. I am envious of your soil supply...
