Thank you Alex! Nematodes... I wouldn't have thought of them. Will search for for info about them and see if I can detect them. If I can find them there is probably a lot of them
Nicola, great to hear from you again! How similar your successes and failures are to mine, it's amazing. My list of successes this year is exactly the same minus the carrots which germinated very poorly this year but I think that was not due to pests but lack of watering. I got overly ambitious and planted too many seeds and then didn't have the time to
water them all every day for those long 14 days...
I think the little black insects you describe are called kirppa in Finnish (flea beetle in English?) and I've had big problems because of them, every year. To the point that I've almost given up growing any brassica at all. For the last two summers (very dry summers in Finland) there has been so many of them that even covering hasn't helped, they've somehow managed to find their way under the covers no matter how carefully I tried to weigh the covers down with stones and despite the fact that the covers were there all the time from the moment I planted the seeds... Kirppas don't like moist weather so this year I've managed to grow say ten seedlings of kohlrabi and four seedlings of broccoli.
There seem to be two methods that work agains kirppas. If you plant the seeds outdoors you have to do so very early (in April), in cold or preferably hot frame so the seedlings are big
enough when the kirppas come. Kirppas first appeared in the middle of May on our farm this year. The other method is to grow the seedligs in a
greenhouse or indoors until they are very strong, big plants and plant them out then. On our farm it is pretty much hopeless to try and plant brassica in rows because of kirppas and also cabbage flies who finish whatever is left from the kirppas.
I have managed to grow a few kohlrabis and maybe one or two broccolis when I hide a few strong seedlings in the orchard. (Then I only have to hope the goats don't escape to the orchard and eat them, like last year
) This year it looks like I might also be able to get some to survive in my tomato bed on a south facing wall.
Growing larger numbers of brassica seems impossible because if I try to plant more than a few in the orchard, they are found by kirppas and eaten to skeletons. I've tried every organic spray,
ash, etc. I've heard of and nothing works. The only thing that helps is if it rains every day.