I thought it might have been snails or slugs but haven't seen any evidence and have resorted to snail bait to make sure. I thought grasshoppers but they don't worry about the other trough or in the ground. No sign of cutworms either and the whole plant disappears not just eaten off.

This photo was taken a while ago and it isn't the trough that is affected.

I read on one of the american forums about an insect that lives in their soils and eats the tops of seedlings. Maybe we have something similar here?

I had a similar problem with some basil seedlings disappearing and couldnt find any snails or slugs around. I had a feeling that whatever was eating my seedlings, was just hanging around waiting for the next lot of seedlings to be planted so I left the troughs empty for a few weeks hoping whatever it was might go elsewhere to find something to eat, and it seemed to work because the last lot of seedlings I put in didnt get eaten. it might be worth a try?

trancegemini

MM, that was my first thought but the 2 troughs are only a metre or so apart and the other one is fine. There has been plenty of grasshoppers but I would expect them to get the other trough as well. I doubt it is ibis as they are close to the house and I haven't seen any bearded dragons in the house yard.

TG, the troughs haven't been planted since October/November and leave it a couple of weeks between seedlings and this was the 4th lot that have gone. I doubted it was compost worms as have been using these troughs for nearly 10yrs with worms but couldn't think of anything else.

As it only affects 1 trough I though it might be something that lives in the soil. May have to resort to removing the soil and putting in new soil but the troughs hold about 4 barrow loads so isn't easy. If it isn't in the soil then it would have been for nothing.

Could you sieve some of the soil in the affected trough to see if there's any sign of grubs or something. My first thought was something like curl grubs or cut worms. If there is something in the soil, I would imagine that it wouldn't be too far down.

Cheers,
Dee.

most likley cut grubs by the sound of it, make some sleaves out of plastic drink bottles or use those used styrene paper cups i like the bottle ones i can get 2 sleave out of each 1.25 or 2ltr bottle. remove the sleaves once the plants have gotten a go on.

len

I took out the top 20cm or so, checking each shovelful carefully, and I didn't find any cutworms or curl grubs. That is unusual around here as usually find at least 1 or 2. The trough was absolutely teeming with large earthworms, probably from all the manure and compost that goes in. Not many compost worms though.

There wasn't a lot of undecomposed organic material left as I was planning on putting carrots in originally, so prefer not to have big lumps of manure, etc. I usually use liquid plant food on carrots. The carrot seeds never came up, so I tried beans, lettuce then tomatoes seedlings but didn't add any compost when I planted them.

Anyway, I put the soil I removed, and as many earthworms as I could, in another garden (on the ground) and topped it up with compost and old horse manure then mulched. I will leave it for a few weeks and try again.

Thanks for your suggestions.